& the need for regular check ups in scleral lens wearers
Lynette Johns OD FAAO FSLS
Progression of ectasia in keratoconus (KC) and pellucid marginal degeneration (PMD) is well known to (R)GP corneal lens specialists. Common complaints include contact lens instability, lens intolerance and discomfort. A patient fit with a scleral lens may experience little or no symptoms of advancing ectasia because the device vaults the cornea until there is contact. In this case, the mechanical contact of the scleral device on the cornea had the potential for significant visual loss, and medical intervention was required.
A 44-year-old man with a history of PMD OU who was wearing our scleral devices from the Boston Foundation for Sight returned after four years in 2009, at which time he complained of severe pain OS at the end of wearing time. There was significant corneal contact with the left device (see photo's below). Additionally, a 4.5 mm active corneal vessel was extending close to the visual axis OS.
We refit OS to enhance the corneal vault, and the acuity was 20/25+2. In the photo below, generous vault allowed for corneal unmolding and advancing ectasia. Lotemax® 0.5% twice daily OS for two weeks was initiated.
An off-label use of the anti-VEGF (vascular endothelial growth factor) medication bevacizumab 1% (preservative-free) twice daily OS in the device reservoir was reviewed with both the patient and the co-managing corneal specialist and initiated one week later. The patient was evaluated locally every 1-2 weeks until his two-month visit with our office.
At the two-month follow-up visit, the patient used Pred Forte® 1% nightly and bevacizumab in the device reservoir twice daily OS. Entering acuity was 20/20-2, and the lens continued to vault over the apex of the cornea. The superior vessel showed modest improvement compared to the initial visit.
A year later, he returned without complaints. The vessel had ghosted as shown in the pictures below. His corneal specialist maintained the steroid, but he no longer used the anti-VEGF treatment. The fit and vault were optimal, and his acuity was 20/25+2.
Fortunately, this patient’s vision remained unaffected and the vessel had ghosted, plus the final device had a generous vault to allow “room to grow” in case there is another 4 years between visits. Because he was symptomatic only at the end of wearing and after removal, perhaps the scleral lens masked a problem that would have otherwise prompted him to return sooner had he been wearing corneal lenses. This case brings to light some issues that are uncertain with scleral lenses. Why did the mechanical contact initiate neovascularization? Typically, corneal lens bearing does not cause neovascularization. If he did not have pre-existing neovascularization, would this active vessel had occurred? Contact lens specialists have the ability to vault even the steepest corneas with a scleral device, but corneal cross-linking in combination with scleral lens fitting may provide long-term success and management of progressive ectatic conditions.
Lim M, Jacobs DS, Rosenthal P, Carrasquillo KG. The Boston ocular surface prosthesis as a novel drug delivery system for bevacizumab. Seminars in Ophthalmology 2009;24:149-55.
Keating A., Jacobs D. Anti-VEGF Treatment of Corneal Neovascularization. The Ocular Surface. 2011 9 (4): 40-51.
Dr. Lynette Johns has been the senior optometrist at the Boston Foundation for Sight since 2005.
She is a graduate of the New England College of Optometry where she completed a residency in cornea and contact lenses. She is adjunct clinical faculty at the New England College of Optometry.
Dr. Johns is a fellow of the American Academy of Optometry and a fellow of the Scleral Lens Education Society.