GP Lens Institute – Scleral Lens Education Society SCLERAL LENS TROUBLESHOOTING FAQs DESCRIPTION This module was developed as a collaborative effort between the GP Lens Institute and the Scleral Lens Education Society. The goal of the module is to answer commonly asked questions pertaining to scleral lens applications, fitting, problem-solving, and lens care. The contributors are Advisory Board members of the GP Lens Institute and leaders in the Scleral Lens Education Society and include the following individuals: Tom Arnold OD; Bruce Baldwin OD; Melissa Barnett OD; Ed Bennett OD, MSEd; Karen Carrasquillo OD, PhD; Greg DeNaeyer OD; Melanie Frogozo OD; Matt Kauffman OD; Langis Michaud OD, MSc; Pam Satjawatcharaphong OD; Muriel Schornack OD; Jeff Sonsino OD; Mindy Toabe OD; Maria Walker OD; Stephanie Woo OD. Note: If you are viewing this PDF online, you may click on the images for larger views. I. DEFINITION, INDICATIONS AND LENS SELECTION 1. How is a scleral lens defined? (Bruce Baldwin, OD) Internationally accepted standards define a scleral lens as a rigid gas permeable lens that is large enough to make contact only with the sclera, completely vaulting over the cornea. A scleral lens can be further subdivided into mini-scleral and full-scleral. Scleral lenses should not be confused with large diameter, custom tinted, soft “sclera” lenses, often bought illegally off the Internet. The Scleral Lens Education Society (www.sclerallens.org) defines scleral lenses via their overall diameter as listed below: NAME DIAMETER FITTING RELATIONSHIP Corneo-Sclera 12.9 – 13.5mm Corneal bearing and scleral touch Semi-Scleral 13.6 – 14.9mm Corneal and scleral bearing Mini-Scleral 15.0 – 18.0mm Scleral bearing and minimal corneal clearance Full Scleral 18.1 – 24+mm Scleral bearing and maximum corneal clearance How are scleral lenses prescribed? Scleral lenses are prescribed by a provider licensed in a state or country to write a legal prescription for an ocular device such as a contact lens. Scleral lenses cannot be legally purchased off the Internet without a prescription. A scleral lens prescription results from a comprehensive examination and lens fitting. Lenses are fit using a set of diagnostic lenses placed on the eye to obtain an accurate fit. Scleral lenses may also be designed with special measuring instruments, or custom molded from an impression of eye shape.
2. Who are the patients that benefit from scleral lenses? (Bruce Baldwin, OD and Melissa Barnett, OD) Anyone who wants to wear contact lenses and has been unsuccessful with any other type of lens wear may be successful with scleral lenses. In particular, patients with a history of eye disease or infection (Figures 1 – 4), trauma, surgery (Figures 5-10), or dry eyes are good candidates for scleral lens wear. Some scleral lens laboratories manufacture bifocal (or multifocal) scleral lenses that may have advantages over other types of multifocal lenses. 1. A patient with Grave's Disease (contributed by Dr. Pam Satjawatcharaphong) 2. A corneal scar from constant lagophthalmos protected and rehabilitated with a scleral lens (contributed by Dr. Melanie Frogozo) 3. Another patient with a corneal scar from constant lagophthalmos protected and rehabilitated with a scleral lens (contributed by Dr. Melanie Frogozo) 4. Persistent epithelial defect protected by a scleral lens (contributed by Dr. Melissa Barnett) 5. Pediatric bilateral aphakic patient wearing scleral lenses (contributed by Dr. Melanie Frogozo) 6. Post penetrating keratoplasty patient (with shunt) in scleral lens wear (contributed by Dr. Pam Satjawatcharaphong) 7. Post penetrating keratoplasty patient with scleral lens wear (contributed by Dr. Melanie Frogozo) 8. Post-Intacs patient wearing scleral lenses (contributed by Dr. Tom Arnold) 9. Post-Intacs patient wearing scleral lenses (contributed by Dr. Maria Walker) 10. Post-Intacs patient wearing scleral lenses (contributed by Dr. Melanie Frogozo)
Scleral lenses are a fantastic option for the management of corneal irregularities on the front surface of the eye or dry eyes. A large diameter lens can vault irregular surfaces such as keratoconus (Figure 11), pellucid marginal degeneration, or ocular trauma (Figure 12) and is also useful in diseases that affect the ocular ecosystem, such as severe dry eye due to Sjögren’s disease, Graft-versus-host-disease (GVHD), Stevens Johnson Syndrome (SJS) (Figure 13), chemical burns, neurotrophic keratopathy and post-refractive surgery complications. Large diameter scleral lens designs are handled and cared for differently than corneal gas permeable (GP) lenses or soft contact lenses. 11. A profile view of a keratoconus patient wearing a scleral lens (contributed by Dr. Tom Arnold) 12. A molded scleral lens on a post golf ball rupture (contributed by Dr. Tom Arnold) 13. Scleral lenses on a patient with Stevens-Johnson syndrome (contributed by Dr. Jeff Sonsino) 3. How can scleral lenses help dry eye patients? (Bruce Baldwin, OD) a. How dry eye patients can benefit from scleral lenses and why. Scleral lenses, when properly fit, vault over the cornea and maintain a fluid chamber between the lens and the eye. This fluid chamber, sometimes called a liquid corneal bandage, can provide a moist, comfortable environment for dry eye patients. (Figure 14) The scleral lens helps to protect the cornea from the outside environment. b. How fitting a dry eye patient differs from an irregular cornea patient. Scleral lenses for dry eye are usually fit similar to other ocular conditions. They are sometimes fit larger than average with a larger fluid chamber. Due to low tear production in dry eye patients and over-production of inflammatory components like mucus, scleral lenses worn for dry eyes often collect material under the lens and deposits on the surface of the lens. This complication may require specific lens design changes that can be difficult to manage. 14. An ocular surface disease patient who could benefit from scleral lenses (contributed by Dr. Tom Arnold)
4.Do scleral lenses reduce the need for corneal transplants? (Bruce Baldwin, OD and Ed Bennett, OD, MSEd) The most common eye disease resulting in a full thickness corneal transplant in 2014, for both the United States and internationally was keratoconus. http://restoresight.org/wp- content/uploads/2015/03/2014_Statistical_Report-FINAL.pdf Keratoconus can cause severe vision loss. If there is no significant scarring of the cornea, contact lenses – including scleral lenses – can restore sight to functional levels, delaying or avoiding the need for corneal transplantion. Other conditions that cause severe vision loss can only be adequately corrected with scleral lenses or surgery. Those patients also have the option to delay surgery. Whether scleral lenses have delayed or prevented corneal surgery has yet to be established. However, as discomfort is the leading cause of contact lens dropout (Begley, Caffery & Nichols, et al, 2000; Hewett, 1984) and as corneal GP lenses on an irregular cornea tend to result in a less than optimum fitting relationship, it is certainly possible that the emergence of scleral lenses has presented practitioners with an option that would all but eliminate corneal surgery for patients experiencing lens-induced discomfort. Bennett (2015) in a poll of prominent specialty contact lens fitters in the United States on this issue, 26 of 34 respondents believed that scleral lenses had reduced the need for corneal transplants in their practice (11 indicated moderate reduction, 15 indicated mild reduction, 4 indicated no change at current time but expect future reduction, and 4 indicated no change). 5. When to select a scleral lens versus other options (i.e., corneal GP, hybrid, custom soft) in keratoconus? (Bruce Baldwin, OD and Stephanie Woo, OD) As of 2016, there are 19 scleral lens manufacturers in North America, and numerous other companies in Europe, India, Australia, and other countries (Tylers Quarterly, http://tylersq.com). With the availability of many lens designs, scleral lenses have become a first option for many practitioners. Other lens types are indicated for fit, comfort or cost reasons. With severe keratoconus, the optic zone of a corneal GP lens may be smaller, which can reduce vision at night. Scleral lenses have larger optic zones, which may help keratoconus patients achieve better vision. If a keratoconus patient complains of lens dislodgement, this could also be reason to try a scleral lens.
6. Scleral lenses as a viable option for healthy eyes? (Bruce Baldwin, OD and Stephanie Woo, OD) a. Are scleral lenses a viable option for healthy eyes, and if so, who are the best candidates? Many practitioners are using scleral lenses for “normal” eyes. Reasons for choosing a scleral lens over a traditional lens type include: dry eyes, high refractive error – including myopia, hyperopia, and astigmatism (Figure 15) – durability, and stability for athletics or work environments. Other candidates include aphakia, anisometropia, and presbyopia. Scleral lenses are also a great option for patients wearing soft toric lenses who complain of fluctuating vision or poor comfort. b. Who are good candidates for multifocal scleral lenses? When traditional soft or rigid multifocal lenses have not given adequate vision or comfort, scleral lenses in multifocal designs can provide good and comfortable distance and near vision. The high quality optics of a GP lens yields impressive near and distance vision with scleral lenses. They are a great option for patients desiring excellent all around vision with good comfort. Patients with presbyopia and astigmatism should consider a scleral multifocal lens as well. Frequent replacement of soft multifocal lenses can be quite expensive. Although a pair of multifocal scleral lenses can also be expensive, the long term cost can be competitive due to the durability of a scleral lens. II. LENS DESIGN AND FITTING 1.Lens Selection (Stephanie Woo, OD) a. When to select a smaller scleral versus a larger scleral lens design? Smaller diameter lenses work well for patients with smaller horizontal visible iris diameter (HVID) and relatively normal cornea shapes. Larger diameter scleral lenses are often used for highly irregular corneas or patients with a large HVID. The diameter selection varies by practitioner. 15. A teenage patient with high hyperopia and astigmatism fit into scleral lenses (contributed by Dr. Melanie Frogozo)
b. Which patients are good candidates for a molded/impression scleral lens design? Any patient who is a candidate for a regular scleral lens is also a candidate for a molded scleral lens. In this case, an impression of the entire ocular surface (including the cornea, limbus, conjunctiva, and sclera) is taken and sent to a laboratory, where a 3-D scanner is used to create an extremely custom device. (Figures 16 and 17) This is a great option for patients with conjunctival anomalies, those needing prism in any direction, and extremely difficult fits. This is also a great option to present to patients who want an extremely unique and custom lens. 2. Can scleral lenses be fit empirically or is a diagnostic fitting set required? (Stephanie Woo, OD) There are a few available instruments that are able to map the corneal, limbal, and scleral shape. Using this technology can improve the success rate when fitting scleral lenses. (Figures 18-20) If you do not have access to this technology, a diagnostic fitting set is recommended. Corneal shapes, eccentricity, and sagittal height all influence the fitting relationship of the scleral lens. Evaluating a scleral lens on the eye after settling 20-30 minutes results in proper assessment of the scleral lens fit. 18.-20. The benefits of a corneal-scleral topographer showing the sMap3D images of a patient with a history of corneal transplant and glaucoma (contributed by Dr. Matt Kauffman) 16. A good mold for an EyePrint scleral lens (AVT) (contributed by Dr. Tom Arnold) 17. A good molded scleral lens fit (contributed by Dr. Tom Arnold) 18. Shows the topography; note that the bleb was superior 19. The green dotted line outlines a 16mm scleral diameter lens 20. The green dotted line outlines an 18mm scleral diameter lens
3. What is the appropriate amount of clearance? (Greg DeNaeyer, OD and Melissa Barnett, OD): a. What would represent an optimum central clearance (before and after settling? The optimum central clearance may be influenced by scleral lens design, diameter, and ocular condition. However, this would amount to200-300 microns pre-settling and 50-200 microns post- settling. (Figures 21-24) There is theoretical and experimental evidence suggesting that oxygen transmissibility is improved with relatively less central corneal clearance. (Michaud, 2012) In general, less central clearance is needed for scleral lenses designed for normal corneas compared to those designed for eyes with ocular pathology or irregular astigmatism. 21. An optimum overall fluorescein pattern of a scleral lens (contributed by Dr. Maria Walker) 22. An optimum overall fluorescein pattern of a scleral lens (contributed by Dr. Melissa Barnett) 23. An optimum overall fluorescein pattern of a scleral lens (contributed by Dr. Melanie Frogozo) 24. An OCT image of optimum central clearance of a scleral lens (contributed by Dr. Tom Arnold) b. How much does a lens settle and how long does it take? A lens can settle up to 200 microns. (Kauffman et al, 2014; Caroline and Andre, 2013; Mountford, 2012) There is both short term settling (during the course of a day – most diurnal settling happens within the first few hours of wear) and long term settling (over months of wear with the initial lens). c. How should the amount of central clearance be determined? The most accurate way to measure central corneal clearance is with anterior segment optical coherence tomography (OCT). (Figures 25, 26) 25. An OCT image illustrating good central clearance with a scleral lens (contributed by Dr. Tom Arnold)
26. An OCT image illustrating good central clearance with a scleral lens (contributed by Dr. Maria Walker) Additionally, the central clearance of a scleral lens can be estimated by comparing the post lens fluid reservoir using slit lamp biomicroscopy (slit beam turned approximately 45 degrees) with the known thickness of the applied scleral lens. (Figures 27-29) For example, if the lens thickness is 300 microns (the dark section of the optic section) and the fluorescein-stained tear film is approximately one half of that thickness, the thickness of the tear film is approximately 150 microns. 27. Viewing the optic section of a scleral lens exhibiting good central clearance (contributed by Dr. Tom Arnold) 28. Viewing the optic section of a scleral lens exhibiting good central clearance (contributed by Dr. Tom Arnold) 29. Viewing the optic section of a scleral lens exhibiting good central clearance (contributed by Dr. Pam Satjawatcharaphong)
Insufficient clearance is shown in Figures 30-32; excessive clearance is shown in Figures 33-35; and a comparison is given in Figure 36. 30. A lens with insufficient central clearance via optic section (contributed by Dr. Tom Arnold) 31. A lens with insufficient central clearance via optic section over the apex of the cone of a keratoconic patient (contributed by Dr. Pam Satjawatcharaphong) 32. A lens with insufficient central clearance via OCT (contributed by Dr. Tom Arnold) 33. An optic section showing excessive central clearance or vault (contributed by Dr. Tom Arnold) 34. An optic section showing excessive central clearance or vault (contributed by Dr. Tom Arnold) 35. An optic section showing excessive central clearance or vault (contributed by Dr. Pam Satjawatcharaphong) 36. A comparison of insufficient, optimum, and excessive central clearance (contributed by Dr. Matt Kauffman)
A very useful tool is the Michigan College of Optometry Scleral Lens Fit Scales (Figures 37, 38): http://www.ferris.edu/ScleralLensFitScales 37. The MCO Scleral Lens Fit Scales showing determination of central clearance
38. The MCO Scleral Lens Fit Scales showing central, limbal, and edge assessment d. What would constitute optimum limbal clearance and how should it be evaluated? The scleral lens should clear the limbus by at least 50 microns. (Figures 39-41) Avoid circumferential limbal bearing of the lens, which will lead to discomfort, keratitis, and neovascularization. 39. A frontal view of a scleral lens exhibiting both good central and limbal clearance (contributed by Dr. Pam Satjawatcharaphong) 40. Good limbal clearance superiorly with a scleral lens (contributed by Dr. Tom Arnold) 41. Good limbal clearance as shown with an OCT (contributed by Dr. Tom Arnold)
4. What would constitute an optimal landing zone and how should it be evaluated? (Greg DeNaeyer, OD) The haptic section of the scleral lens should rest evenly on the scleral surface without compression of blood vessels or areas of edge lift. (Figures 42-48) Circumferential edge lift can result from an excessively flat fitting lens. Quadrant specific edge lift is usually the result of the back surface of a lens not properly aligning to a non-rotationally symmetric scleral shape. Commonly this is observed when fitting a spherical back surface scleral design on an eye with significant scleral toricity. 42. Good overall scleral fit with optimum scleral landing (contributed by Dr. Tom Arnold) 43. Good overall scleral fit with optimum scleral landing (contributed by Dr. Melissa Barnett) 44. More magnified view of a good overall scleral fit with optimum scleral landing (contributed by Dr. Pam Satjawatcharaphong) 45. A view of the inferior sclera of a lens that is exhibiting good landing on the sclera (contributed by Dr. Pam Satjawatcharaphong) 46. A view of good scleral landing superiorly (contributed by Dr. Melanie Frogozo) 47. An OCT image of optimum edge landing on the sclera (contributed by Dr. Tom Arnold)
48. An OCT image of optimum edge landing on the sclera (contributed by Dr. Maria Walker) 5. When would a back surface toric haptic be recommended? (Greg DeNaeyer, OD) Most patients have significant scleral toricity and would benefit from a back surface toric haptic scleral design. (Figures 49-51) In these cases, improved alignment will improve patient comfort and decrease reservoir debris. (Figure 52) 49. Peripheral bubbles observed due to lack of lens alignment with the sclera (contributed by Dr. Pam Satjawatcharaphong) 50. Peripheral bubbles observed due to lack of lens alignment with the sclera (contributed by Dr. Pam Satjawatcharaphong) 51. Peripheral bubbles observed due to lack of lens alignment with the sclera (contributed by Dr. Tom Arnold) 52. A toric scleral lens aligning well with cornea and sclera (contributed by Dr. Greg DeNaeyer)
Use a back surface toric if edge lift is observed in opposing quadrants. (Figures 53-55) 53. Poor superior alignment and edge lift of a scleral lens with spherical peripheral optics (contributed by Dr. Greg DeNaeyer) 54. Inferior edge lift with a scleral lens with spherical peripheral optics (contributed by Dr. Melanie Frogozo) 55. Inferior edge lift with a scleral lens with spherical peripheral optics (contributed by Dr. Melanie Frogozo) Corneo-scleral topography and fitting software enables a custom back surface toric design for each individual eye. Focal areas of haptic adjustment – including a microvault or a notch – can be needed in cases with significant scleral obstacles, such as pingueculae or conjunctival blebs. (Figures 56-63) 56. A microvault with a 17mm diameter lens (contributed by Dr. Tom Arnold) 57. Demonstration of a scleral lens with a notch (contributed by Dr. Matt Kauffman) 58. and 59. Elevated conjunctiva with spherical lens (58) and with a notch (59) (contributed by Dr. Pam Satjawatcharaphong) 60. Notch application in a patient with a history of glaucoma and a corneal transplant (contributed by Dr. Matt Kauffman) 61. Notch application for a patient with a pinguecula (contributed by Dr. Pam Satjawatcharaphong) 62. Use of a notch with patient with elevated conjunctiva (contributed by Dr. Melissa Barnett) 63. Notch application for a keratoconic/Intacs patient with a pinguecula (contributed by Dr. Melanie Frogozo)
6. When would a front toric lens be indicated? (Greg DeNaeyer, OD) Front surface toricity should be prescribed for residual astigmatism. The lens will be ballasted by either double slab-off prism or back surface toricity. III. PROBLEM-SOLVING 1. What are common causes of reduced vision with scleral lenses? (Muriel Schornack, OD) a. Front surface deposits Causes. There are many conditions that may cause poor anterior surface wettability. (Figures 64- 69) These include poor tear chemistry, especially in patients with severe dry eyes from conditions such as GVHD, SJS, severe Meibomian Gland Dysfunction (MGD), blepharitis, rosacea and atopic conditions. In addition, oily substances may enter the tear film, or solutions that are not compatible with the lens material may contribute to poor surface wettability. 64. Lens surface nonwetting (contributed by Dr. Pam Satjawatcharaphong) 65. Poor surface wettability (contributed by Dr. Stephanie Woo) 66. Localized areas of poor surface wettability (contributed by Dr. Maria Walker) 67. Lens surface deposits (contributed by Dr. Stephanie Woo) 68. Lens surface filming (contributed by Dr. Maria Walker) 69. Lens surface film (contributed by Dr. Melanie Frogozo) Treatment. Managing patient expectations: if a patient is wearing a scleral lens to protect the cornea because they have poor-quality tear film, we’re basically trading one dry surface for another. These patients may need to remove the lens several times daily for cleaning and conditioning. We also need to recognize that we need to use materials with very high oxygen permeability (Dk) values for scleral lenses. These materials tend to be more hydrophobic (and lipophilic): not a great combination for these patients. Aggressive treatment of ocular surface disease is imperative. There are a variety of options to manage front surface debris depending on the cause. Fogging may be due to oil-based lotions, makeup, and soaps. Ask patients about hand
soap and change soap to contact lens hand soap or acne treatment hand soap. Recommendations include the following. i.Remove the lens and clean with an extra-strength cleaner. ii.Consider plasma treatment or retreatment of lens. iii.Treat ocular surface disease aggressively. iv.Apply makeup, facial moisturizers, etc. after lenses are inserted. v.Manually polish the surface with an approved gas permeable polishing solution. vi.Moisten a cotton swab or removal plunger with solution and clean the surface on-eye. b. Flexure 1. How is lens flexure diagnosed and managed? Sphero-cylindrical over-refraction is step one. If unexpected cylinder is found, measure keratometry or topography over the lens. If either show cylinder that matches over-refractive cylinder with a spherical scleral lens, it is likely that the lens is flexing. Incorporating toricity in the lens flange or increasing flange thickness may reduce flexure. 2. What are the causes and management of tear reservoir debris? (Muriel Schornack, OD and Melissa Barnett, OD) a. Tear reservoir debris is a relatively common problem, often resulting in patient symptoms of midday fogging of vision. (Figures 70, 71) Several theories have been proposed, none have been definitively proven as of yet, although there was a study that analyzed lipid composition of post-lens fluid in high-debris compared to low-debris patients. (Walker, 2014) The high- debris patients had higher lipid concentrations. These include the following: 70. Mid-day fogging resulting from tear reservoir debris (contributed by Dr. Maria Walker) Theory #1: Poor edge design or inadequate landing zone / lens edge alignment allows for uptake of debris from the tear film into the post-lens fluid reservoir. Debris gets in, but cannot get out, thus collecting over time. Theory #2: Corneal epithelial cells turn over relatively rapidly. When a scleral lens is in place, those cells are released from the ocular surface, but become entrapped behind the lens. This may be more pronounced if the patient is using a solution that is incompatible with their ocular surface to fill the bowl of the lens prior to application. 71. OCT image of debris in the tear film (contributed by Dr. Tom Arnold) It is likely that it is both of these factors (and probably several others) that contribute to this phenomenon. We’re really in the very beginning stages of investigation here.
b. Bubbles in the tear reservoir. Scleral lens discomfort may be a result of bubbles trapped in the lens fluid reservoir. There are a variety of sources that cause bubbles to occur. Bubbles may be caused by incorrect application techniques or if an aerated solution is used to fill the bowl of the scleral lens. The training and re-training of scleral lens application is critical. If an insertion bubble occurs, it is important to remove and reinsert the lens. If the lens is not removed, corneal desiccation can occur. If the scleral lens landing zone has misalignment, bubbles may result. Edge lift in one or more quadrants or a lens with excessive movement may allow bubbles to enter. In these scenarios, revision of the fit is required. Other management methods: 1. Sometimes patients need to remove and refresh the lens in order to eliminate debris in the reservoir. Additionally, patients may use a more viscous solution in the bowl of the lens with lens application. 2. Modifying the scleral lens fit may be needed to reduce excessive tear exchange. Adding toric peripheries, decreasing the central vault or reducing the diameter may all be options to manage reservoir debris. 3. How important is scleral lens decentration? (Ed Bennett, OD) As the nasal sclera is typically more elevated than the temporal sclera it often results in some temporal decentration of the lens. (Caroline, 2013) (Figures 72-74) 72. Inferior-temporal decentration of a scleral lens (contributed by Dr. Pam Satjawatcharaphong) 73. Inferior-temporal decentration of a scleral lens (contributed by Dr. Maria Walker) 74. An OCT image of temporal decentration of a scleral lens (contributed by Dr. Tom Arnold) In addition, the mass of a scleral lens can also result in some inferior decentration as well. Often this is not a significant problem but can, in some cases, result in a change in the lens-to-cornea fitting relations with a resultant localized area of corneal bearing. Decreasing lens mass and either decreasing lens diameter (which also decreases mass) or adding toric haptics if a larger diameter (≥ 16mm) scleral lens may help provide better centration. Decentration can result in increased high order aberrations. (DeNaeyer, 2014) Retroillumination photography to identify the center of the scleral lens optics, pupillometry to identify the center of
the pupil, and wavefront aberrometry to quantify high order aberrations can assist in the design of a lens with a decentered optical zone. 4. Poor Patient Compliance (Melissa Barnett, OD) Poor patient compliance may also lead to complications such as extended wear and/or over-wear. In some rare cases, extended wear of scleral lenses is medically necessary; this requires close monitoring and follow-up. Patient education is key to insure proper compliance. Questions at each visit include average wearing time of scleral lenses, wearing time at the time of the visit, all solutions used, and any additional products. 5. Scleral Lenses and Hypoxia: (Langis Michaud, OD) a. How is scleral lens-induced hypoxia diagnosed? There are three type of studies published that investigated the occurrence of corneal hypoxia induced by scleral lens wear. Two articles (Michaud, 2012; Jaynes 2015) were based on a theoretical model, and both confirm that scleral lens wear may induced corneal edema if the lens thickness exceeds 250 um and if the clearance under its surface is higher than 200 um. Obviously, because the tear fluid layer is wedge- shaped, this affects the central cornea only. Clinical studies have since been published confirming that scleral lens wear can be associated with an induced corneal swelling varying from 1 to 4% in normal corneas (Compañ 2014, Ng 2015, Miller 2015), in keratoconus (Soeters 2015) and especially in cases where the endothelial cell layer is compromised (Lau 2015, Riff 2015). These studies are based on pachymetry. However, it is not still clear if hypoxia is the only factor involved in corneal swelling during scleral lens wear. More interestingly, an in vivo study also confirmed a reduction in the oxygen diffusion to the cornea if tear fluid layer thickness increases (Giasson 2015). In this study, authors used the EOP approach and evaluated, directly on the cornea with probes, the oxygen consumption after exposure to several gases (reference curve) and then after wear of scleral lenses fitted with 200 and 400 microns of clearance. Their results are highly significant in that increased clearance reduces oxygen diffusion to the cornea by 30%. In fact, considering an optimal Equivalent Oxygen Percentage (EOP) level of 9.9% to avoid corneal hypoxia (Benjamin 1988), scleral lenses (18.0 mm in diameter, with an average lens thickness of 310 microns) fitted with 200 um of clearance lead to an EOP value of 9.0%, while the same lens with 400 microns decreased EOP to 6.2%.
Considering these results, it is now a proven fact that scleral lenses are inducing chronic corneal edema when the lens thickness is higher than 250 um and when clearance exceeds 200 um. (Figure 75) Vincent (2016) suggested that this level of hypoxia may be considered benign, comparable to physiological edema seen after sleeping. If the value is the same (2- 4%), this type of comparison cannot be made because physiological edema does not last for more than 1h00 while induced edema remains present for all wearing hours and more, the time for restoration to occur when cornea is exposed to air. 75. Hypoxia induced by a scleral lens (contributed by Dr. Jeff Sonsino) At this point, nobody knows what will be the impact of such a chronic corneal edema, especially on compromised tissues. More research is needed to analyse the long-term outcome, but in the meantime, it is recommended to fit scleral lenses with the lowest clearance possible and to manufacture scleral lenses as thin as possible. It should be noted that hypoxia is not clinically visible before reaching 8-10% level, which is not the case here. Also, edema does not affect the limbal area, clearance over the limbus being limited under 100 um. Consequently, neovascularization is not triggered. Notwithstanding this absence of visible clinical signs, studies showed that edema occurs with unknown long-term impacts. There are ways to alleviate this hypoxic stress, especially by designing thinner lenses fitted with less clearance. This could be more easily achieved when using scleral lenses of smaller diameter (<16 mm). Larger lenses (>16 mm) have to be fitted with higher clearance, to be well supported, and made thicker, in part to keep their geometrical stability. They are mainly used to treat ocular surface diseases, where the risk/benefits is positive in light of hypoxic stress. b. What oxygen transmission(Dk/t) is necessary in a scleral lens to minimize corneal edema? Referring to Harvitt-Bonnano (1999) criteria, it is 33 for daily wear and 125 for extended-wear. Scleral lenses DK should be evaluated in conjunction with the tear fluid layer, both acting as resistors in series. Sclerals are made of high DK material varying from 100 to 150 Fatt units, and the tear layer is characterized by a DK of 80 Fatt Units. These values are influenced by the thickness of the lens and the thickness of the tear fluid layer (clearance) which reduces the oxygen permeability. To respect Harvitt-Bonnano criteria, scleral lenses should be 250 thick and fitted with 200 um clearance maximum, if using a DK material of 150 Fatt units. Oxygen can come from other sources, such as tear exchange and tear mixing. However, it is know that tear exchange is very limited once scleral lenses are settled on the conjunctival surface. Vance (2015) evaluated the rate of exchange at 0.2%/minute. As for tear mixing, it was also proven that it is not contributing significantly to replenish oxygen under the scleral lenses.
6. What causes bulbar conjunctival redness and how should it be managed? (Langis Michaud, OD) Bulbar conjunctival redness may come from different sources (Figure 76): Infection Mechanical trauma /irritation /Blood vessels compression Inflammation Infection. The first article published in a peer-reviewed journal about scleral lenses dates back to 1946 (Carlson, 1946). Since then, 219 other contributions have been published, increasing knowledge about scleral lens wear (Pud Med Search1). Among these, only ten relate to adverse events such as acute red eye, microbial keratitis, and complications after post-surgery fittings. Specifically, microbial keratitis was related to extended wear, non-compliance, or an eye with severe ocular surface disease (Zimmerman, 2014; Fernandes, 2013, Walker, 2015). Patients that are immunosuppressed can also be more at risk than others. The overall safety of the devices was also assessed in eight review papers, which reported no significant negative impacts from scleral lens usage. Of these published articles, 133 described the successful use of scleral lenses fitted on irregular corneas to improve ocular surface, including 14 retrospective studies. 76. Localized conjunctival vessel congestion with scleral lens wear (contributed by Dr. Tom Arnold) Mechanical trauma/Irritation/Compression. It is now known that the sclera is a non- symmetrical rotational toric surface. At 15 mm, sclera displays, in average around 1.5 D of toricity, which increases up to 5D at 18 mm of chord length. (Van der Worp, 2010). Scleral lenses designed with spherical haptics will display meridional lens misalignment, leading to impingement in some quadrants. This triggers a compression of the conjunctival tissue and its vasculature when lenses are steeper than the scleral profile. Clinically, this is visible as a blanching of the conjunctiva where the pressure is present. As a consequence, blood flow is impinged, causing engorgement before and after this area. (Figures 77-83) This becomes visible as redness outside the lens edge and at the margin of the area where the pressure is exercised. Visser et al (2006) found an increase in wearing time and comfort when designing scleral lenses with toric haptics, offering a better overall alignment with the conjunctiva in every quadrant. Currently, it is highly recommended to design lenses with back-toric peripheral curves for any scleral lens prescribed with a diameter of 16 mm or larger. 1 Pub Med Search with the keywords scleral, scleral contact lenses, fluid-ventilated contact lenses, and PROSE between Jan 20 and Jan 24, 2016.
77. Localized impingement of the conjunctival vasculature (contributed by Dr. Tom Arnold) 78. Localized impingement of the conjunctival vasculature (contributed by Dr. Pam Satjawatcharaphong) 79. Impingement of the conjunctival vasculature (contributed by Dr. Pam Satjawatcharaphong) 80. Impingement of the conjunctival vasculature (contributed by Dr. Tom Arnold) 81. Impingement of the conjunctival vasculature (contributed by Dr. Stephanie Woo) 82. Moderate impingement of the conjunctival vasculature (contributed by Dr. Greg DeNaeyer) 83. Severe impingement of the conjunctival vasculature (contributed by Dr. Greg DeNaeyer) Inflammation. Inflammation is not widely cited as a source of adverse events related to scleral lens wear. However, Walker (2015) suggests that it is underestimated and can lead to discontinuation of scleral lens wear. With an increased usage of scleral lenses, inflammation – not related to an infectious event – will probably become more clinically visible. Inflammatory mediators, released from the ocular surface can remain trapped under the scleral lens, which may contribute to raise the inflammatory response. In addition, cellular debris and toxins released from the normal corneal metabolism are also kept trapped under the scleral lenses, knowing that tear exchange is practically absent once the lens is settled. This could be another triggering factor to initiate inflammatory reaction such as overall redness and sterile corneal infiltrates.
7. If the lens results in persistent awareness/discomfort, what are possible causes and management options? (Langis Michaud, OD) The great majority of the time, lens awareness and discomfort are caused by lens-to-lid interactions, mostly when the lenses are fitted too flat on the conjunctival tissue. At this time, edge stand-off occurs, which raises the level of lens awareness and discomfort. (Figure 84) Every lens being different, practitioner should consult the fitting guide to resolve this issue: by modifying the peripheral curves only, or by altering the overall lens fitting. One other cause may be the presence of an air bubble trapped under the lens. Due to the tear stagnation under scleral lenses, bubbles are not moving. The cornea under the bubble dries and the patient feels burning and discomfort sensations. Most of the time, these bubbles are due to mishandling, at insertion. Revisiting handling procedures, using more viscous solution to instill in the bowl and/or designing a smaller diameter scleral lens can help. Discomfort can also occurs after 4-5 hours of wear. This is called the tight lens syndrome and is triggered by a lens becoming too steep, sealing off the ocular surface after a few hours of wear. (Figures 85, 86) Some conjunctival tissues are smoother and scleral lenses sink in them more. This can contribute to develop a tight lens syndrome. (Figure 87) 84. Edge standoff with a scleral lens (contributed by Dr. Melissa Barnett) 85. An OCT image of edge "toeing" or embedded into conjunctiva (contributed by Dr. Tom Arnold) 86. An OCT image of edge "toeing" or embedded into conjunctiva (contributed by Dr. Tom Arnold) 87. Extreme toeing of a scleral lens edge into a boggy conjunctiva (contributed by Dr. Tom Arnold) To manage this issue, revisiting the fitting is essential: reducing the lens vault and the clearance over the cornea is a first step to do, then flattening the peripheral curves may also help. Going smaller will also help to meet both requirements. 8. What is conjunctival prolapse and how should it be managed in a scleral lens wearer? (Langis Michaud, OD) Conjunctival prolapse represents an entrapment of the conjunctiva, draping over the cornea, near the limbal region, under a scleral contact lens. (Figures 88-96) It occurs in the inferior quadrant on patients with loose conjunctival tissue (conjunctivochalasis), more so in elderly patients. Several conditions should be present to lead to chalasis: large scleral lens, decentered, and fitted with higher clearance over the limbus, and on a patient where the conjunctival tissue is lower than
the cornea. This was also associated with pellucid-marginal degeneration due to inferior corneal typical profile. Finally, it was reported that handling the lens, with too much pressure, can increase the risk of inducing prolapse. (Miller, 2015). 88. Mild inferior conjunctival prolapse (contributed by Dr. Tom Arnold) 89. Mild conjunctival prolapse (contributed by Dr. Tom Arnold) 90. Mild conjunctival prolapse (contributed by Dr. Pam Satjawatcharaphong) 91. Mild conjunctival prolapse (contributed by Dr. Maria Walker) 92. Mild conjunctival prolapse (contributed by Dr. Maria Walker) 93. Superior conjunctival prolapse (contributed by Dr. Maria Walker) 94. Mild conjunctival prolapse in a post radial keratotomy patient (contributed by Dr. Tom Arnold) 95. Moderate conjunctival prolapse (contributed by Dr. Tom Arnold) 96. Moderate conjunctival prolapse (contributed by Dr. Pam Satjawatcharaphong) This phenomenon is considered benign, but the real potential for negative outcome in the long term is not known. Considering that the conjunctiva remains draped over the stem cells for many hours, it is probably wiser to alleviate prolapse occurrence. One way to accomplish this is to limit the clearance over the limbus by modifying the peripheral curves or selecting a smaller diameter scleral lens. Handling should be revisited as well.
9. What causes corneal staining in a scleral lens wearer? How should it be managed? (Langis Michaud, OD) As it is the case for other types of contact lenses, staining associated with scleral lens wear can originate from different sources: mechanical, hypoxic, and chemically induced. Mechanical. Especially for scleral lens beginners, handling lenses could be an issue. Especially with larger lenses, which are more difficult to handle resulting in a corneal erosion, which is visible as a mechanical staining. (Figure 97) Proper lens insertion and removal education should be provided. Compliance to the proper procedures should be reassessed during follow-up visits. 97. Post contact lens wear corneal staining (contributed by Dr. Tom Arnold) 98. Corneal bearing with a scleral lens (contributed by Dr. Tom Arnold) 99. Inferior corneal bearing with a scleral lens (contributed by Dr. Pam Satjawatcharaphong) 100. Corneal staining resulting from corneal bearing with a scleral lens (contributed by Dr. Pam Satjawatcharaphong) Mechanical staining can also occur from a lens that results in central/paracentral bearing. (Figures 98-100) Hypoxic. Microcystic edema can occur if the clearance over the limbus is too high and if there is a fluid layer stasis. This is especially true for patients fitted with high convex scleral lenses. Chemically induced. This is the primary cause of corneal staining related to scleral lens wear. The use of preserved products to fill the contact lens, before insertion, allows preservative agent to remain in contact with the cornea during all wearing hours. This may initiate a toxic reaction visible as a diffused punctate keratitis. (Figure 101) 101. Solution toxicity staining with a scleral lens wearer (contributed by Dr. Pam Satjawatcharaphong) This is a very similar reaction as the one described as SICS in soft lenses (Luensmann, 2012). This can be overturned by the use of non-preserved saline or non- preserved artificial tear solutions.
10. What should be done if you observe air bubbles when evaluating a scleral lens on the eye? (Langis Michaud, OD) Bubbles come first due to mishandling during insertion. (Figures 102, 103) Some fluid is lost, and then an air bubble comes into play. It can also occur from a misalignment of the lens in one quadrant. (Figure 104) 102. Large bubble resulting from scleral lens insertion (contributed by Dr. Matt Kauffman) 103. Large bubble resulting from scleral lens insertion (contributed by Dr. Matt Kauffman) 104. Peripheral bubble resulting from poor peripheral lens alignment (contributed by Dr. Karen Carrasquillo) If there is a significant edge stand-off, then a tiny air bubble can be formed under the surface of the lens at every blink. Then the small bubbles gather together and are generating a bigger one. A spherical lens on a highly toric cornea or scleral can result in peripheral bubbles. Toric haptics can often be beneficial in these cases. Bubbles can alter visual acuity if they are located centrally. They can also initiate discomfort because the cornea will dry under their surface. This is why bubbles are not tolerable, even if they are small, if they don’t move. Depending on the cause, central bubbles can be eliminated by revisiting handling instructions or by using more viscous solution in the bowl (less likely to spill over during insertion). For those generated by a misalignment, prescribing back-toric haptics can fix the issue. 11. What does a compression ring indicate when a scleral lens is removed? (Langis Michaud, OD) This is a sign of a very tight lens. This can come from a lens vaulting too much over the ocular surface, or a lens with peripheral curves not well aligned with the conjunctival profile. Ideal clearance over the cornea is 200 um once the lens is stabilized. Then managing the scleral lens fit to achieve this objective can help to alleviate compression. If this is not enough, modifying peripheral curves, by flattening the outer ones, will fix the issue. Flattening the curves without reducing the overall clearance is not recommended, because it will transfer the pressure nearest to the limbus.
12. What is epithelial bogging and is it significant? (Ed Bennett OD) According to Caroline and Andre (2015) upon lens removal the ocular surface looks “water-logged” and irregular. (Figures 105, 106) It could result from constant contact between the corneal epithelium and a sodium chloride inhalation solution that contains no nutrients or electrolytes to benefit the cornea. It is often transient, lasting the first 4 – 6 weeks of lens wear. The patient is typically asymptomatic, and epithelial bogging may represent a relatively benign condition, although an argument for the use of a solution with nutrients for the epithelium or the use of a “cocktail approach” in which a non- preserved artificial tear is used in combination with a sodium chloride solution can be made. IV. CARE AND PATIENT EDUCATION (Mindy Toabe, OD) 1. What solution should I use to fill the bowl of the scleral lens? LacriPure by Menicon is approved by the United States Food and Drug Administration(FDA) for insertion with scleral lenses. This solution is available as a 5 mL sterile unit, single use non- preserved, non-buffered 0.9% NaCl (normal saline) solution. [(510(k) Number K151768] LacriPure can also be used to rinse lenses prior to insertion, remove debris and bacteria after the disinfection process and to rinse lens cases or lenses as needed during the day. Inhalation saline solution is an off-label use as an insertion solution for scleral lenses. This solution is available in boxes of 100 as 3 or 5 mL sterile unit dose single use non-preserved 0.9% sodium chloride inhalation solution. Inhalation saline solution is not buffered and does not have any preservatives or active ingredients. Inhalation saline solution may be obtained with a prescription from a pharmacy in the United States and may be covered by medical pharmaceutical insurance programs. Alternatively, sodium chloride 0.9% inhalation solution vials may be purchased without a prescription online. 2. What care systems can be used with scleral lenses? Hydrogen peroxide solutions with a concentration of 3% (30,000 ppm) are the first choice for use with scleral lenses. Hydrogen peroxide care systems need to be neutralized with a platinum catalytic disc to breakdown the hydrogen peroxide into water and oxygen prior to inserting scleral lenses. The platinum disc becomes less effective over time and should be replaced about every 90 days (100 cycles). Hydrogen peroxide solutions neutralize into saline within 4 to 6 hours and do not provide constant disinfection throughout the storage period. (Bergenske, 1994) 105. Epithelial bogging (contributed by Dr. Tom Arnold) 106. Epithelial bogging (contributed by Dr. Maria Walker)
Use this disinfection process on a daily basis as case contamination is increased in part-time wear where the solution is not replaced on a regular basis. Scleral lenses should not be stored in hydrogen peroxide solution for more than one night since the disinfection process is not continuous. This care system work especially well for those patients sensitive to chemicals and preservatives in multipurpose solutions. Multipurpose solutions for rigid gas permeable lenses can also be prescribed for use with scleral lenses. This solution option is convenient and can be used for both cleaning and disinfecting the scleral lens if there is a concern about using a multi-step regimen. Multipurpose solutions should be stored at room temperature and replaced every three months after the bottle is opened. This care system solution should not be reused in the case and should be changed daily. Scleral lenses should not be stored in saline solution or tap water since these options do not provide disinfection against microorganisms. (Zimmerman A, Marks A, 2014) 3. How do you clean scleral lenses? Scleral lenses should be cleaned daily by rubbing the lens with a surfactant combined with isopropyl alcohol. Cleaning a scleral lens in the palm of the hand with a lens cleaner prepares the lens surface for disinfection, kills microorganisms, and helps to remove debris that gets trapped under the lens. Discard cleaning solution bottles every three months due to risk of microbial contamination. (Donzis P, et al, 1987) 4 How do you rinse scleral lenses? Rinse scleral lenses with saline solution, not tap water. It is important not to use tap water to rinse scleral lenses or their storage cases due to the association of acanthamoeba keratitis with tap water use. (Seal DV, et al, 1999) Rinsing the scleral lenses with saline solution to remove the cleaning agent will enhance disinfection and avoid risk of chemical toxicity of the cornea. 5. What type of case can be used to store scleral lenses overnight? A hydrogen peroxide solution needs either a large disinfection case or two smaller cases (one for each lens). A basket case increases the risk of chipping or breaking a scleral lens when inserting or removing the lens. The baskets should remain closed while inserting the lens into the case for the disinfection process. A large basket case, the PROSE Disinfection Case, is available from dryeyezone.com. This case does not have a neutralizing disc attached to the bottom of the basket. Thus, a neutralizing disc needs to be taken off of a hydrogen peroxide basket case and placed in the bottom of the PROSE Disinfection Case. A multipurpose disinfection system maintains disinfection over time and requires a case large enough for the solution to cover the lens completely. (Seal DV, et al, 1999)
6. How should a scleral lens case be cleaned and stored during the day? The most effective way to clean a storage case and remove biofilm is to rub the case, rinse the case using a multipurpose solution or saline solution, wipe the case with a tissue and then air-dry the case face down (multipurpose solution case) or on its side (hydrogen peroxide basket case). (Tilia D, et al, 2014; Vijay A, et al, 2014) This process removes excess moisture and decreases the risk of microbial keratitis and airborne contamination. (Hall BJ, Jones L, 2010; Wu Y, et al, 2015) Placing a case on a clean tissue prevents it from coming into contact with a contaminated surface. Lens cases should not be stored in the bathroom or near the toilet to reduce contamination. 7. What is the importance of washing hands prior to lens care? Washing hands with soap and water rather than just water or not at all decreases the risk of contamination while using a dirty towel will increase the chances of infection. Hands should be dried completely using a clean towel to avoid spreading contamination to the scleral lens. Mechanical friction of the hands or in the storage case does remove contaminants; however rubbing the case without washing hands with soap and water causes increased contamination compared to not rubbing lens cases because dirty fingers can transfer contaminants. (Wu Y, et al, 2015) 8. How often should a scleral lens case be replaced? To decrease microbial contamination and biofilm formation, eliminate tap water use and discard cases on a monthly basis. The FDA recommends replacing cases and solutions every 90 days. (www.fda.gov) 9. What devices are available to apply a scleral lens? Insertion devices used with scleral lens include large plungers. The DMV scleral cup is a large plunger with a hole in the center to limit suction to the lens. (Figure 107) A DMV vented scleral cup, with a hole on the top and bottom of the plunger, is also available, and is used to limit suction completely. Both plunger designs can be used with a scleral lens for insertion although the DMV vented scleral design may be easier for insertion since it alleviates suction allowing for a smoother insertion process. Pinching the plunger at the junction between the cup and the handle will remove the plunger from the scleral lens in the event of the plunger remaining on the scleral lens upon insertion. A small plunger can be used for insertion but does require balancing the lens on the small plunger as well as pinching the plunger from the scleral lens upon completion of insertion. 107. Large plunger used for inserting a scleral lens (contributed by Dr. Karen Carrasquillo)
10. What techniques are available for inserting a scleral lens? There are two methods for scleral lens insertion: the three-finger approach and the inserter method using an insertion device. With the three-finger approach, the thumb, index, and middle fingers of the dominant hand are used to create a stand for scleral lens insertion. With the inserter method, an insertion device, or large plunger, is prepared by wetting the plunger’s surface with one to two drops of sterile non- preserved saline solution. Hold the outside edge of the lens and place it on the insertion device. The lens is then overfilled with sterile non- preserved saline solution appearing convex above the lens. If this is being performed in-office, a fluorescein strip should be dipped into the saline such that the fluorescein pattern can then be observed. (Figures 108, 109) The eyelids are held open with the non-dominant hand. As the solution touches the eye, the lens is inserted gently. The eyelids are released once the lens is on the eye. 11. Should inspection of the lens be performed after lens insertion? Look in the mirror after inserting the scleral lens and inspect the eye for air bubbles that could cause discomfort and decrease vision. An air bubble creates a dry area underneath the lens and can cause corneal desiccation over time. Air bubbles may appear upon insertion if the head pulls back and is not parallel to the ground causing the lens to tilt upon insertion and allowing air between the solution and the eyeball. If an air bubble is present, the lens should be removed and reinserted. 12. What are some clinical pearls to ensure patient success when inserting a scleral lens? It is advised to sit in a chair, lean forward with the chin towards the chest and the head parallel to the ground. The eyes should face a mirror on the table covered with a clean towel. The eyelids are held wide open with the pointer finger on the upper eyelid and middle finger or thumb on the lower eyelid of the non-dominant hand. While holding the eye open, the lens is moved straight up to the eye. Overfill the bowl of the lens with sterile non-preserved saline so that the saline appears as a convex or round surface above the lens. 108. A plunger filled to the top with saline and fluorescein dye (contributed by Dr. Jeff Sonsino) 109. A plunger slightly overflowed with saline with fluorescein dye (contributed by Dr. Stephanie Woo)
Look straight down toward the mirror on the table or look at the plunger or the black hole of the plunger while inserting the lens. If needed, the other eye is closed. If using a large plunger without a hole, the plunger is gently squeezed in order to release suction. 13. What is recommended when a patient experiences difficulty with scleral lens insertion? During insertion the lens may touch the lid and decenter on the plunger or the fingers requiring the patient to reposition the lens. If a lens is not centered on the plunger initially, air bubbles may enter under the lens. Lid control is key to successful lens insertion. Hold the lids open with one hand and don’t let go of the lids until the DMV plunger has been removed from the scleral lens. Keep your face parallel to the floor as the lens is inserted in the eye. This position will help to maintain the fluid in the bowl of the lens so that air does not get underneath the then during insertion. There are other non-approved, non-preserved single use options available to fill scleral lenses. A more viscous artificial tear such as carmellose sodium (Celluvisc by Allergan) or carboxymethylcellulose sodium (Refresh Optive Preservative-Free from Allergan) may be used in combination (50/50) with non-preserved 0.9% sodium chloride inhalation solution or may be used alone. The increased thickness of the combination solution prevents debris from migrating underneath the lens. The combination solutions also help increase comfort, prevent loss of fluid with scleral lens insertion and avoid air bubbles. 14. What devices are available to remove a scleral lens? The most efficient tool for the removal of scleral lenses is a removal device, the DMV Ultra remover. This is a small plunger with suction capabilities to hold on to the large lens during the removal process. The DMV Classic can also be used for removal. The DMV 45 angled lens remover is angled at 45 degrees to eliminate the hand from interfering with vision during scleral lens removal with a mirror. 15. What techniques are available for removing a scleral lens? Removal of a scleral lens can be performed with the manual two finger method or with a removal device, or small plunger. With the manual two-finger method, look down, then move the lower eyelid outward while applying mild pressure to eyeball. Next, the lower eyelid is gently pushed with the index finger underneath the lower edge of the lens and the lens is removed. 110./111. Lens removal with a suction cup (contributed by Dr. Melissa Barnett) Top: proper placement of suction cup on the inferior region of the lens. Bottom: lift down and out to remove lens.
With the removal device, hold the eye open and apply the small plunger to the lens in the peripheral inferior or superior quadrant, not in the center of the lens. The lens is removed by releasing suction of the lens on the eye with the removal device. (Figures 110, 111) 16. What are some clinical pearls to ensure patient success in removing a scleral lens? Sit in a chair and place a clean towel on a flat table prior to scleral lens removal. Place a make-up mirror on the table and look into the mirror while removing the lens. Wet the surface of the plunger with one to two drops of sterile non-preserved saline solution. Prepare the eye with preservative-free saline or artificial tears to wet the eye and loosen the lens prior to scleral lens removal. Pressing just below the lens at the edge of the lens with the plunger may be helpful in breaking the seal of the lens allowing for a bubble to form under the lens to loosen the lens prior to removal. 17. How are insertion and removal devices for scleral lenses disinfected? Insertion and removal devices, also known as plungers, should be disinfected with alcohol after each use and then allowed to air dry. Cleaning is critical as an old device can become cracked, leave residue on the lens surface, and not provide good suction on the scleral lens. The Boston Foundation for Sight recommends that devices should be replaced every 6-12 months, or sooner if the edges become rough, uneven, or if suction is not sufficient. Insertion and removal devices may not be readily obtainable at the local pharmacy. An on-line resource for the devices is the dryeyeshop.com. 18. Where can I find useful tools for scleral lens handling? a. See Green Lens Inserter The See Green Lens Inserter by Dalsey Adaptives (http://dalseyadaptives.net/store/), is available both with and without a stand. (Figure 112) The lighted plunger helps center the device for application. The stand holds the plunger and lens in place prior to application. This is helpful for patients who have unsteady hands or for those who need both hands to hold their eyelids open. b. EZi Scleral Lens Applicator Another tool is the EZi Scleral Lens Applicator by Q- Case Inc. (http://ezibyqcase.com/). (Figure 113) This device is placed on the finger like a ring and has a base for scleral lens application. This design provides stability and allows patients to apply scleral devices with one finger. 112. Lens insertion with the use of the Green Lens Inserter from Dalsey Adaptives (contributed by Dr. Karen Carrasquillo) 113. Lens insertion with the EZi Scleral Lens Applicator by Q- Case, Inc. (contributed by Dr. Jeff Sonsino)
c. Number 8 “O” Ring A third option is a #8 O ring that is available at any hardware store. O ring dimensions are 3/8” x 9/16” x 3/32”. The scleral lens rests on the O ring on a patient’s finger, which can allow for stable application. d. Orthodonic Ring An additional option for scleral lens insertion is a sterile orthodonic ring placed on a patient’s hand. These come in packages of 100 and may be used for single use insertion of scleral lenses. V. RESOURCES (Pam Satjawatcharaphong, OD) 1. Where can I go for resources to help with scleral lens education? There are many resources – notably available from the GP Lens Institute and the Scleral Lens Education Society - that provide general scleral lens education in the form of case reports, webinars, publications, lectures, and workshops. Numerous resources can be found online from the sites listed below: Scleral Lens Education Society (SLS): http://www.sclerallens.org Gas Permeable Lens Institute (GPLI): http://www.gpli.info/scleral-lenses Contact Lens Manufacturers Association (CLMA): http://www.clma.net A Guide to Scleral Lens Fitting, 2nd edition, by Eef van der Worp: http://commons.pacificu.edu/mono/10 Michigan College of Optometry Scleral Lens Fit Scales: http://www.ferris.edu/ScleralLensFitScales 2. How can the laboratory consultant help with scleral lenses? The consultants from each laboratory understand scleral lens fitting concepts well, and are particularly well-versed in their own designs. They can be very helpful resources when it comes to selecting the appropriate initial diagnostic lens based on individual patient needs, as well as troubleshooting difficult fits. Consultants may also have recommendations for appropriate lens materials and solutions to optimize patient comfort and vision with scleral lenses. 3. What information should I provide to the laboratory consultant to optimize success with scleral lenses? Most lenses can be successfully fit in office using a diagnostic lens set and slit lamp examination, and verbal descriptions of the fit are often sufficient for laboratory consultants to help with decisions regarding parameter changes. However, if your office has a corneal topographer, anterior segment OCT, or slit lamp camera (including adaptors for smart phones), this additional information may also be helpful to provide to a consultant.
At this time, there are some limited options for scleral imaging/molding techniques that may allow for more successful empirical lens ordering in the future. Visionary Optics sMap 3D: http://www.visionary-optics.com/products/smap3d Eaglet-Eye Eye Surface Profiler: http://eaglet-eye.com/eye-surface-profiler-now-on-sale EyePrintPro: www.eyeprintpro.com REFERENCES 510(k) Number K151768, Trade/Device Name: Menicon Saline Rinse Solution Regulation Number: 21 CFR 886.5928, Regulation Name: Soft(Hydrophilic) Contact Lens Care Products; Regulatory Class: Class II; Product Code: LPN, MRC; Dated: June 30, 2015 Benjamin, WJ and RM Hill, Human cornea: individual responses to hypoxic environments. Graefes Arch Clin Exp Ophthalmol, 1988. 226(1): p. 45-8 Bergenske, P. Optometry clinics: the official publication of the Prentice Society: Contact Lens Disinfection 1994; 4(1): 47-60. Caroline PJ. Managing the top 10 large diameter complications. Presented at the Global Specialty lens Symposium, Las Vegas, NV, January, 2013. Caroline PJ, Andre MP. “Life” beneath a scleral lens . . . epithelial bogging. Contact Lens Spectrum 2015;30(3):56. Caroline PJ, Andre MP. Scleral lens settling. Contact Lens Spectrum 2013;28:32-39. Carlson J.J. Silbert M. The technique of fitting scleraform contact lenses; determination of the shape of the human eye by insertion of spherical contact lenses. Opt J Rev Optom 1946, Oct;83(20):34-6. Compañ V. Oliveira C. Aguilella-Arzo M. Molla S. et al. Oxygen diffusion and edema with modern scleral rigid gas permeable contact lenses. Investig Ophthalmol Vis Sci, 55 (2014), pp. 6421–6429. DeNaeyer G. Scleral lens decentration. Presented at the Global Specialty Lens Symposium. Las Vegas, NV, January, 2014. Donzis, P., Mondino, B. et al. Microbial Contamination of Contact lens Care Systems. American Journal Of Ophthalmology. Oct 1987;104:325-333. Fernandes M. Sharma S. Polymicrobial and microsporidial keratitis in a patient using Boston scleral contact lens for Sjogren's syndrome and ocular cicatricial pemphigoid. Cont Lens Ant. Eye 2013, Apr;36(2):95-7
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Vijay A, Willcox, M, Zhu, H et al. Contact Lens Storage Case Hygiene Practice and Storage Case Contamination. Eye Contact Lens. 2014 Sept 16. Soeters N, Visser ES, Imhof SM, Tahzib NG. Scleral lens influence on corneal curvature and pachymetry in keratoconus patients. Cont Lens Anterior Eye. 2015 Aug;38(4):294-7 Vincent SJ, Alonso-Caneiro D, Collins MJ, Beanland A, Lam L, Lim CC, Loke A, Nguyen N. Hypoxic Corneal Changes following Eight Hours of Scleral Contact Lens Wear. Optom Vis Sci. 2016 Mar;93(3):293-9. doi: 10.1097/OPX.0000000000000803. Visser ES. Visser R. Van Lier HJJ. Advantages of toric scleral lenses. Optom. Vis. Sci., 83 (2006), pp. 233–236. Walker MK. A proposed mechanism for scleral lens induced conjunctival prolapse. Scientific poster presented at the Global Specialty Lens Symposium, Las Vegas, NV, January, 2014. Walker MK, Bergmanson JP, Miller WL, Marsack JD, Johnson LA. Complications and fitting challenges associated with scleral contact lenses: A review. Cont Lens Anterior Eye. 2016 Apr;39(2):88-96. Worp E. Van Der. A Guide to Scleral Lens Fitting [monograph online]. 1st ed. Forest Grove, OR: Pacific University; 2010. Wu, Y, Willcox, M, Stapleton, F. The Effect of Contact Lens Hygiene Behavior on Lens Case Contamination. Optom Vis Sci 2015, Feb;92(2):167-174. Zimmerman AB. Marks A. Microbial keratitis secondary to unintended poor compliance with scleral gas-permeable contact lenses. Eye Contact Lens 2014, Jan;40(1):e1-4.