Scleral Lenses as Therapeutic Devices

As the number of eye care practitioners who fit scleral contact lenses increases, the number of ways to use these devices as therapeutic entities also continues to grow. Scleral lenses offer one avenue for optometrists who wish to increase their medical eye care offerings.

Scleral contact lenses are prosthetic devices that vault the cornea, rest on the bulbar conjunctiva, and help to bathe the cornea in tear film. They are custom-designed and fabricated to fit the unique shape of each patient’s scleral toricity. These gas permeable contact lenses are generally 15 to 23 mm in diameter and are filled with a preservative-free solution before they are inserted. The reservoir can also be used as a drug delivery system for a variety of corneal diseases, as I discuss below.

PROTECTING THE CORNEA

After a corneal insult in a normal, healthy eye, changes in tear composition and cellular remodeling begin the process of epithelial wound healing. This process typically occurs over 7 to 10 days.¹ If the corneal stroma is damaged, healing may take 8 weeks or more. Without proper treatment, a corneal epithelial defect may persist, causing discomfort and predisposing patients to increased risks of infection, corneal thinning, and, in severe cases, perforation.

Scleral contact lenses protect the corneal epithelium and assist in reepithelialization by establishing an environment that provides continuous hydration. The devices also protect the corneal epithelium from mechanical and environmental forces that may impede its healing.¹

Healing PEDs

A study by Rosenthal et al found that, in 13 patients, extended wear of scleral lenses had a statistically significant affect in promoting the healing of persistent epithelial defects (PEDs) that had been unresponsive to other modes of treatment.² With the exception of one patient who wore the lens continuously, extended wear in this study was interrupted by brief periods of removal once or twice during each 24-hour period for cleaning.²

He et al reported on a series of three patients who wore scleral lenses for 24 hours.³ These patients demonstrated rapid recovery of their PEDs and improvement in vision after 2 to 4 weeks of treatment. The lenses were removed after 12 hours for cleaning and then reinserted.

Khan et al reported a case series in which eight eyes of eight patients with PED (Figure 1) were treated with scleral lenses.¹ Five patients were fit with only scleral lenses with no antibiotic added, two patients wore lenses with moxifloxacin and Celluvisc Eye Drops (Allergan) in the bowl of the lens, and one patient wore a lens containing moxifloxacin, Celluvisc Eye Drops, and serum tears. At the conclusion of the series, all eyes reepithelialized in a mean time of 11 days, VA improved in seven patients, and there were no reported complications.¹

Treating CNV

VEGF is a prominent proangiogenic factor in many conditions involving neovascularization. Neovascularization that involves the cornea can cause impaired vision and corneal opacification and can increase the risk of graft failure if a corneal transplant is warranted. Anti-VEGF therapy has become the first-line treatment for retinal angiogenic disease, and anti-VEGF agents have recently been used as topical therapy for corneal neovascularization (CNV).

Yin et al conducted a retrospective study of 13 patients with various corneal diseases that resulted in CNV (Figure 2).⁴ The study included seven patients with Stevens-Johnson syndrome, two with ocular chronic graft-versus-host disease, two who received corneal transplants, one patient with contact lens–related corneal ulcer and limbal stem cell deficiency, and one patient with familial dysautonomia. Median duration of treatment with the anti-VEGF agent bevacizumab (Avastin, Genentech) was 6 months (range, 3 months–10 years). Two patients with Stevens-Johnson syndrome reported reduced debris in their devices and improved photophobia and discomfort while using bevacizumab, and their therapy was continued with varied frequencies (not more than twice daily) for 14 months and 10 years.⁴ Twelve of the 13 patients had regression of CNV, and 10 had improved BCVA with treatment. Neovascularization progressed in one eye after bevacizumab was discontinued.⁴ There were no ophthalmic or systemic complications.

AN ACE UP THE SLEEVE

The studies described above point to a future in which scleral lenses can serve as therapeutic modalities for patients with advanced ocular surface disease. These lenses also hold the potential to foster cohesive management between optometry and ophthalmology in complex cases, for patients who would otherwise have no other nonsurgical options for improving their vision and comfort. I foresee the use of these devices continuing to expand as the ways to use their benefits evolves. For scleral lens fitters, these treatments have the potential to offer many patients a chance for improved quality of life and of vision.