Contact Lens Spectrum Supplements

Special Edition 2017

Contact Lens Spectrum

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C O N T A C T L E N S S P E C T R U M S P E C I A L E D I T I O N 2 0 1 7 c l s p e c t r u m . c o m 40 SCLERAL LENSES F or many years, practitioners have had tremendous success using scleral lenses to correct irregular astigmatism and to treat ocular surface disease, even in pa- tients with compromised corneas. Scleral lenses were the earliest type of contact lens, manufactured first from blown glass scleral shells and then from polymethyl methacrylate (PMMA). 1,2 Early designs had several shortcomings, in- cluding poor oxygen transmissibility, which led to lens- induced corneal edema, corneal hypoxia, and eventu- ally discontinuation of lens wear. In addition, each lens was handcrafted and impossible to replicate if broken or lost. With improved materials and reproducible designs, these shortcomings have been overcome. Scleral lenses are applied with preservative-free fluid in the bowl of the lens, which continuously bathes the ocular surface. This creates a smooth anterior optical surface, correcting for corneal irregularities and improv- ing visual acuity. If higher-order aberrations (HOAs) are present, the post-lens tear reservoir under a scleral lens can help to minimize the effect of HOAs by eliminating corneal surface irregularities. Indications for modern scleral lenses are expanding to include not only irregular corneas but also mild-to- severe ocular surface disease. 3 Scleral lenses can be used for corneas with regular, normal, prolate shapes without disease, ectasia, or irregularities; however, coexisting conditions may be present, such as ocular surface dis- ease, including dry eye, meibomian gland dysfunction, blepharitis, or demodex. Some practitioners are now us- ing scleral lenses to correct refractive error for normal, healthy eyes, and each year, manufacturers introduce new lens designs for healthy eyes. Why use scleral lenses for normal, healthy eyes? They can be used to correct most refractive errors, in- cluding myopia, hyperopia, astigmatism, and presby- opia. I believe they can also help prevent contact lens dropout and contribute to practice growth. Interest in scleral lenses continues to rise as more practitioners embrace this technology. In a 2016 survey, almost 60% of practitioners reported their use of scleral lenses had increased. 4 With this growing interest in using scleral lenses for healthy corneas, we need substantial new re- search on the long-term effects of scleral lens wear for both irregular corneas and healthy eyes. In this article, I discuss emerging applications for scleral lenses in healthy eyes and offer some fitting and troubleshooting tips. PREVIOUS CONTACT LENS FAILURES The reason for contact lens dropout is multifactorial, according to the reports of the Tear Film and Ocular Surface Society International Workshop on Contact Lens Discomfort. 5 Contact lens discomfort, which even- tually leads to dropout, may be caused by lens-related or environmental factors or both. According to these reports, multiple aspects can be modified to improve comfort. Modifiable contact lens parameters are mate- rial, design, fit and wear, and lens care. Environmental factors that cannot be altered include inherent patient factors (age, gender, ocular and systemic disease), modi- fiable patient factors (medication compliance), the ocu- lar environment, and the external environment (humid- ity and air quality). Even with advances in contact lens technology, drop- out rates range from 15% to more than 20%. 6-9 Under the age of 45, comfort issues are the primary reason for con- tact lens dropout. 5 After age 45, vision and comfort are almost equally stated as the reason for dropout. 10 In the soft lens-wearing population, 93% of patients were not wearing multifocal contact lenses at the time of dropout. Ex p a n d i n g i n d i c a t i o n s f o r h e a l t h y e y e s c r e a t e o p po r t u n i t i e s f o r p a t i e n t s a t i s f a c t i o n a n d p r a c t i c e g r o w t h M E L I S S A B A R N E T T, O D SCLERAL LENSES FOR EVERYONE

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