December 2015 Online Photo Diagnosis
BY LUCIANO BASTOS
Scleral Lens Complications in Advanced Keratoconus
This image shows the right eye of a keratoconus patient who wore the same scleral lenses for four years and only recently returned for a follow-up visit in November 2015. The lens was bearing significantly on the cornea, resulting in corneal distortion, central erosion, neovascularization, and corneal edema. Also, the right lens had a crack that did not extend through the entire thickness of the lens.
Figure 2 shows the appearance of the right lens at the initial fitting evaluation in 2011 and at the recent follow-up visit in November 2015.
Figure 2. (Left) The scleral lens at the initial fitting in 2011 after six hours of wear, and (right) the same scleral lens in November 2015.
The patient was 17 years old in 2011. He returned for a follow-up visit early in 2012 and, at that time, everything was fine. However, the lens vault was within 150 microns, and the patient did not return for subsequent planned follow-up visits because he said the lenses felt fine. Although we have observed in our clinic that scleral lens wear can help some keratoconic corneas remain stable, probably because there is no mechanical stress on the epithelium, it is expected that young keratoconus patients will experience episodes of ectatic progression at least until they are 25 to 30 years old. In this case, it is clear that the patient’s ectasia had progressed, so the vault was not sufficient to maintain a proper fit.
Over time, as the ectasia progressed, the scleral lens started to exert mechanical pressure on the apex of the ectasia, which led to the pictured condition (Figure 3). This could have been avoided if the patient had returned for his prescribed folow-up visits.
Figure 3. (Top left) Corneal distortion, (top right) corneal neovascularization near the limbus, (bottom) the fluorescein pattern shows a small dot of erosion at the corneal apex.
We suspended lens wear and treated the patient for one week with Epitezan (Allergan [Brazil]) and nonpreserved artificial lacrimal tears (Hylo-Comod [Ursapharm]). Once the corneal health improved, we refit the patient with a scleral lens that had a higher sagittal height (sag) so it could better vault the corneal apex. The erosion resolved, the cornea returned to a healthier condition, and the neovascularization was signifcantly reduced. We also made clear to the patient the importance of follow-up visits to avoid such complications in the future.
Fitting scleral lenses in young keratoconus patients requires the understanding that a smaller vault may not be enough over time. Keratoconus generally progresses more aggressively in young patients. The scleral lens sag and design should be adequate to result in a vault of no less than 150 microns. In this case of a young keratoconus patient, a greater vault may have been safer, and proper patient education of the importance of regular follow-up visits is crucial to maintain a successful lens fit.
Mr. Bastos is the director and clinical instructor of specialty contact lenses at the Instituto de Olhos Dr. Saul Bastos (IOSB) and is the director and specialty lens consultant of Ultralentes, a small laboratory specializing in GP and scleral lens designs in Porto Alegre, RS, Brazil.