Scleral Lens Education at GSLS
BY EDWARD S. BENNETT, OD, MSED, FAAO
The Global Specialty Lens Symposium (GSLS) provided more than 100 hours of specialty contact lens education and numerous presentations pertaining to GP lenses. Here are some highlights.
Scleral Lenses...New Opportunities New Challenges (Caroline et al) This presentation stated that excessive limbal clearance (versus alignment) is more likely to result in post-tear lens fogging with scleral lenses. Limbal alignment can be improved using asymmetrical peripheries or smaller scleral designs (i.e., corneo-scleral) as larger lenses tend to have more peripheral clearance. A more viscous filling solution can also help reduce fogging. Ideally, initial clearance should be approximately 300 microns to allow for 100+ microns of settling and to reduce the risk of hypoxia from reduced oxygen transmission through an excessive tear reservoir after settling (i.e., >250 microns).
In terms of cleaning the surface of a scleral lens that tends to exhibit non-wetting during the day, a suction cup with GP wetting solution can be used across the front surface in a “squeegee” effect to scrub the surface clean.
To minimize bubble formation behind the lens after application, the authors recommend overfilling the lens with non-preserved filling solution to create a positive meniscus. In addition, beginning new patients with a more viscous solution would result in less spillage. For patients who are apprehensive about applying lenses, refrigerating the filling solution beforehand will provide a cold sensation to signal that the lens is coming in contact with the eye.
What’s the Solution? Update on Contact Lens Care and Compliance (Gromacki) Using a thicker, unit-dose nonpreserved filling solution was presented as a viable option in patients whose lenses may exhibit areas of touch or minimal clearance; these solutions provide extra lubrication and corneal protection. Patients who have difficulty removing the suction cup from lenses after application can also cut off the bottom of the suction cup to ensure that it will not adhere to the lens.
Comparison of Scleral vs. Silicone-Hydrogel Disposable Multifocal Lenses (Michaud) Results from this crossover study comparing a soft multifocal lens to a small scleral lens exhibited some parity, although the scleral lens was found to be more comfortable and showed a slight advantage in vision.
Rotationally Asymmetrical Scleral Lenses—Indispensable Treating Method of Ocular Surface Diseases (Manczak) This detailed three examples in which an 18mm asymmetric scleral lens design changed the life of the lens wearers, including a patient who has chronic graft-versus-host disease with resulting major dryness, recurrent corneal ulcers, conjunctival scarring, and sub-epithelial corneal scarring; a patient who has Lyell’s Syndrome (toxic epidermal necrosis) with resulting ulcers causing dryness and severe photophobia; and a patient who had experienced brain tumor surgery resulting in persistent corneal neurotrophic ulceration, superficial and deep neovascularization, and lagophthalmos. Overall, asymmetric scleral lenses resulted in preservation of vision, pain reduction, and much improvement in quality of life and contact lens success.
Clinical Evaluation of a Novel Hybrid Contact Lens for Irregular Cornea: One Year Results (Severinsky) The use of an aspheric, reverse curve hybrid design with a 60-Dk/t (i.e., 130-Dk) GP center and a center thickness of 0.22mm on 49 eyes (24 keratoconus, 23 keratoconus and corneal cross-linking, and two post-penetrating keratoplasty) of 35 patients was evaluated. The success rate was 80%, with dropouts resulting from staining either adjacent to the GP-soft juncture or centrally.
The 10th annual GSLS will be held Jan. 21 to 24, 2016 at Caesars Palace in Las Vegas. CLS
For references, please visit www.clspectrum.com/references and click on document #232.
Dr. Bennett is assistant dean for Student Services and Alumni Relations at the University of Missouri-St. Louis College of Optometry and is executive director of the GP Lens Institute. You can reach him at email@example.com.