Laser scleral microporation proposed as accommodation restoration therapy - PDF Document

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  1. 34 JUNE 1, 2018::Ophthalmology Times Special Report ) SURGICAL & CLINICAL SOLUTIONS FOR PRESBYOPIA Laser scleral microporation proposed as accommodation restoration therapy Visual axis untouched, meaning patients can benefi t from future corneal, cataract surgeries By Laird Harrison; Reviewed by Sunil Shah, MBBS, FRCOphth, FRCS, FBCLA, and AnnMarie Hipsley, DPT, PhD LASER SCLERAL microporation appears promising as a treatment for presbyopia in em- metropic subjects, according to Sunil Shah, MBBS, FRCOphth, FRCS, FBCLA. Unlike most treatments for presbyopia, the technique restores some natural ability to ac- commodate along with some extended depth of focus (EDOF) by increasing compliance in the sclera, said Dr. Shah, professor, Aston Uni- versity, Birmingham, UK. The procedure—in which a laser creates tiny micropores in the sclera—is an advanced iter- ation of a technique pioneered a decade ago, laser anterior ciliary excision (LaserACE). In a preliminary trial of the new approach, sub- jects gained a median 4.5 lines of near and intermediate visual acuity. The technique is based on new understand- ing of the etiology of presbyopia and the bio- mechanical mechanisms involved in accom- modation. While most attention in the past has focused on changes in the lens, recent discoveries have highlighted the role of other structures, including the sclera and choroid. All ocular tissues stiffen or lose elasticity as the eye ages just like many other connective tissues in the body. Age-related changes in the eye result largely from the steady increase in crosslinks or bonds between polymer chains in the collagen and elastin that form the fibrils and microfibrils in the sclera, Dr. Shah said. Current treatments com- pensate for the lost accom- modation rather than restor- ing it. Whether induced by manipulating multifocality, monovision, or depth of focus by using laser refractive proce- dures or created with contact lenses, all of these procedures may decrease binocularity, stereopsis, and uncorrected distance visual acuity. Although monovision is the most popular treatment alter- native to reading glasses, most people with presbyopia can- not tolerate it, Dr. Shah said. Likewise, corneal presby- opic correction—an attempt to create a bifocal or multifo- cal cornea—can also result in loss of binocularity, ste- reopsis, or distance vision. In laser scleral microporation, an Er:Yag laser uses 225-µm spots to create a 5- x 5-mm ma- trix of micropores in a variety of densities and number that are 225 µm in diameter in four oblique quadrants of the eye. According to Dr. Hipsley’s postulate, the cre- ation of the micropore matrix over five key critical zones of biome- chanical and physiological impor- tance improve the compliance of the sclera in these regions to yield to accommodative forces from the ciliary muscles and extralenticu- lar anatomy, thus restoring the efficiency of the accommodation mechanism. In a trial of 12 patients, mean monocular uncorrected visual acu- ities at near (40 cm), intermediate (60 cm), and distance (4 m) im- proved from +0.65 logMAR, +0.54 logMAR, and +0.20 logMAR, respectively, preopera- tively, to +0.27 logMAR, +0.15 logMAR (p = 0.0087), and +0.11 logMAR, respectively, at 1 month postoperatively. Similarly, mean binocular uncorrected vi- (FIGURE 1) Schematic representation of the laser scleral microporation procedure over the fi ve critical anatomical zones of physiological and biomechanical importance. take-home ◗ With laser scleral microporation, a laser creates tiny micropores in the sclera. In a preliminary trial, subjects gained a median 4.5 lines of near and intermediate visual acuity. D I V I N G D E E P E R In her published manuscript, “Visio- Dynamics Theory: A Biomechanical Model for the Aging Ocular Organ” (Jaypee Books, 2003), AnnMarie Hipsley, DPT, PhD, described an age-related progressive “scleroscle- rosis” which decreases scleral com- pliance in response to forces ap- plied during accommodation, thus reducing accommodative efficiency. Some researchers have estimated that ex- tralenticular structures could account for up to 2 D of accommodation, and the aging of the structures might result in 1 to 2 D of lost accommodation. (FIGURE 2) Microporations in four oblique quadrants over the fi ve critical anatomical zones of physiological and biomechanical importance. (Images courtesy of AnnMarie Hipsley, DPT, PhD) sual acuities at near (40 cm), intermediate (60 cm), and distance (4 m) improved from +0.6 logMAR, +0.47 logMAR, and +0.19 logMAR, respectively, preoperatively, to +0.14 logMAR, +0.08 logMAR, and -0.04 logMAR, respectively, Continues on page 35 : Laser scleral

  2. 35 JUNE 1, 2018::Ophthalmology Times Special Report ) SURGICAL & CLINICAL SOLUTIONS FOR PRESBYOPIA The improvements appear long-lasting. In a study on macaque monkeys, the research- ers found cellular infiltration at the margin of the micropores at 1 month, Dr. Hipsley noted. The inflammatory response subsided after that. The researchers noted coagulative necro- sis at the margins of the micropores. “Overtime, the inflammatory response re- ceded leaving clear histological evidence, how- ever, that the healed micropore was not as dense as the surrounding untreated sclera,” Dr. Hipsley said. Researchers also reported that scleral fibro- blasts migrated and proliferated into the mir- copores. Collagen treatment reduced this re- sponse in the early period after the procedure. So far, these changes do not appear to cause a reversal of the effects of the microporation. The researchers are still collecting longer-term data with this version of the procedure. But they have followed for over 10 years patients who underwent a preceding similar scleral pro- cedure, LaserACE. These patients have continued to enjoy re- duced presbyopia, Dr. Shah said. “The 10-year data we’ve got shows it doesn’t come back,” he said. “There is some progres- sion with age as would be expected, but you don’t get a complete loss of effect. We need longer-term data with the new system.” The newer system—laser scleral micropo- ration—is faster and easier because it treats four quadrants in 14 seconds each, employ- ing a scanning technology. LaserACE was per- formed with a fiberoptic handheld probe and performed only 1 spot at a time. An advantage to laser scleral microporation compared with other presbyopia treatments is that the visual axis remains untouched. This means patients can benefit from future corneal or cataract procedures, such as receiving en- hancements to LASIK or accommodative IOLs, the researchers noted. Q LASER SCLERAL ( Continued from page 34 ) at 1 month postoperatively. No patients expe- rienced complications that decreased best-cor- rected visual acuity or quality of vision, he said. “It’s topical anesthesia, and they barely feel anything because you’re only doing a very tiny microporation,” Dr. Shah said. “They don’t have any problem at all, and very little discomfort afterward either.” Some evidence suggests decreasing ocular rigidity may affect the development of glau- coma and age-related macular degeneration as well as presbyopia. With the loss of elas- ticity, the sclera puts compression and load- ing stresses on underlying structures, and can affect blood flow through the sclera and optic nerve, according to Dr. Hipsley. An earlier iteration of the procedure (Laser- ACE) has shown a statistically significant re- duction in IOP from a mean of 13.56 mm Hg at baseline to 11.74 mm Hg after 2 years, she said. Investigations of the effects of laser scleral mi- croporation on intraocular pressure are ongoing. SUNIL SHAH, MBBS, FRCOPHTH, FRCS, FBCLA E: sunilshah@doctors.net.uk This article was adapted from Dr. Shah’s presentation at the 2018 meeting of the American Society of Cataract and Refractive Surgery. He is a consultant to AceVision. ANNMARIE HIPSLEY, DPT, PHD E: ahipsley@acevisiongroup.com Dr. Hipsley is founder and CEO of AceVision. OCULAR SURFACE or out-of-pocket expenditures that might make patients hesitant to move forward. It has been our experience, however, that patients appreci- ate knowing how they can maximize outcomes and improve healing, with the ancillary ben- efit of tacitly letting them know we will take steps to ensure they are happy with results. surgeons look to further refine outcomes and ensure patient happiness, the subtle change to being more proactive about managing the ocular surface perioperatively represents an important step in achieving the goals that pa- tients want. Q ( Continued from page 33 ) while reducing markers of inflammation and ocular surface disease index score by 12 weeks.1 At least two mechanisms have been pro- posed—the breakdown of omega-3 fatty acids results in anti-inflammatory molecules and/or the use of omega-3 fatty acids alters the com- position of meibomian gland secretions such that they no longer induce blockade of the glands.1 Either mechanism (or both) increases meibomian gland secretions that reduces tear film evaporation.2 Getting neutraceuticals on board prior to surgery maximizes the poten- tial for the tear film to respond to the surgical insult and heal properly. Additional measures may be added as needed. We typically start with artificial tears and oral neutraceuticals, with discretionary use of cyc- losporine or a similar topical therapy based on severity. If MGD is suspected, we offer a cer- tain treatment (LipiFlow, TearScience). Some colleagues may contend that each op- tion adds expense in the form of co-payments References C O N C LU S I O N Optimizing the ocular surface prior to refrac- tive surgery is not intended to be a panacea. Whether a patient is set to undergo PRK, LASIK, or even newer options like SMILE, the proce- dure will disrupt the corneal nerve plexus. Transient dryness is almost an inevitability, and if it is not mentioned prior to surgery, it becomes more problematic. At the same time, with safe/effective treat- ments at surgeons’ disposal, both cost and convenience become the most relevant barri- ers to taking action. These can be overcome through proper education about what clini- cians are recommending and the science be- hind the options. Technology in modern refractive surgery is better then ever, and likewise, results are more predictable and accurate than ever. As 1. Epitropoulos AT, Donnenfeld ED, Shah ZA, Holland EJ, Gross M, Faulkner WJ, Matossian C, Lane SS, Toyos M, Bucci FA Jr, Perry HD. Effect of oral re- esterified omega-3 nutritional supplementation on dry eyes. Cornea. 2016;35:1185-1191. 2. Macsai MS. The role of omega-3 dietary supplementation in blepharitis and meibomian gland dysfunction. Trans Am Ophthalmol Soc. 2008;106:336–356. SHILPA D. ROSE, MD P:301/825-5755 Dr. Rose is a board-certifi ed ophthalmologist practicing with Whitten Laser Eye and Chesapeake Eye Care in both Chevy Chase, MD and Charlotte Hall, MD. Dr. Rose is a consultant for PRN Neutraceuticals.