"You don’t need eyes to see, you need vision." – Maxwell Frazer
Some say that hindsight is twenty-twenty. The joy of working with scleral lenses is the continual learning process and the opportunity to offer new options with this wonderful technology. Not only have lens designs improved, my fitting philosophy with this technology has definitely changed over the last decade. I queried global scleral lens experts to share their words of wisdom and how their fitting strategies have changed over time.
A common question from practitioners interested in getting started with scleral lenses is which diagnostic fitting set to select. Dr. Stephanie Woo recommends to "get to know one scleral lens design in and out before attempting to use another lens. Getting a good grasp on one lens and its design is crucial and builds confidence before diving into more designs." Dr. Langis Michaud emphasizes the importance of learning basic scleral lens fitting prior to fitting actual patients. When he received his first scleral lens fitting set, he did not have any instructions and “tried to fit my first patient like a regular GP—no fluid in the bowl!” There are many resources for learning how to fit scleral lenses, hands on workshops at meetings or in your practice, the Scleral Lens Society and Gas Permeable Lens Institute websites and webinars, to name a few.
According to Dr. Barry Eiden, "you don’t know what you don’t know". Dr. Eiden "surely had no idea of the complexity of the corneo-scleral shape early on. Only through the wonderful research that has been done in this area and the use of AS-OCT imaging of lenses on eyes along with corneo-sceral profiling technologies have I been able to process this information and then with the availability of customized scleral lens designs better address the needs of our patients."
Dr. Greg DeNaeyer states "the most significant aspect of fitting scleral lenses that has changed for me is fitting lenses from a corneo-scleral topography measurement. It removes the guess work and inefficiency of diagnostic lenses. Scleral topography now allows us to design free-form scleral lenses that exactly matches the conjunctival scleral shape. This eliminates many of the lens fit complications that we often encounter when trial fitting branded designed lenses. Additionally, these scleral lenses can have customized optic zones that allow for even corneal clearance despite an asymmetric ectasia."
Dr. Karen Lee recommends a minimalist approach. "If you find yourself making change after change and the eye really didn’t seem like it would be a difficult fit, you have probably over-complicated things with all those initial modifications." In these situations, she recommends seeking help from laboratory consultants sooner.
When fitting very ectatic corneas or proud grafts, Dr. Tom Arnold states that "sometimes the 14.0 – 17.0 mm lenses are not sufficient so do not be afraid to go to larger diameters when needed. There are a number of lenses available up to 20.0 mm. Sometimes bigger really is better."
Dr. Daddi Fadel emphasizes the importance of lighting when evaluating a scleral lens. "Imaging the clearance with a slit lamp is crucial to estimate clearance thickness and to evaluate how the lens settles. In some cases, the view is dark, and it may be difficult to identify the area to asses with precision. The use of room light may help enhance the view, so the practitioner will be able to compare the clearance with previous images in each exact area." (Figures 1 and 2)
These are wonderful pearls to support your scleral lens practice. Many thanks to all of the scleral lens experts for their contributions to this edition of Scleral Lens Monthly.
Figures 1 and 2. Evaluation of corneal clearance with fluorescein. Figure 1 is without room light and Figure 2 is with room light.
Dr. Barnett is a principal optometrist at the University of California Davis Eye Center in Sacramento, specializing in anterior segment disease and specialty contact lenses. She is the past president of the Scleral Lens Education Society. She is an advisor to and/or has received honoraria or travel expenses from AccuLens, Alcon, Alden Optical, Allergan, Bausch + Lomb, Bruder, Contamac, CooperVision, EveryDay Contacts, Johnson & Johnson Vision, Ocusoft, Paragon Bioteck, RaayonNova, ScienceBased Health, Shire, SynergEyes, and Visioneering Technologies.