Today's Scleral Lenses

BY JEFFREY J. WALLINE, O.D., & KARLA ZADNIK, O.D., Ph.D.
NOV. 1996

In the past, PMMA scleral contact lenses caused excessive corneal hypoxia and complications such as edema and neovascularization. Now, new materials allow maximum wearing time with minimum side effects. Rigid scleral lenses can be a safe and successful modality for a variety of ocular conditions in which conventional contact lenses have failed and when surgery is undesirable or contraindicated.

CASE STUDY: THE SCLERAL LENS ALTERNATIVE

Ruben and Guillon (1994) reported the case of a 48-year-old woman with neurofibromatosis who suffered from bilateral fifth and seventh cranial nerve palsies following surgery for bilateral acoustic neuromas. A diffuse punctate epithelial keratitis and progressive neovascularization did not respond to tear supplements, punctal occlusion and multiple tarsorrhaphies. Best corrected visual acuities were 20/200 in both eyes. A bandage soft contact lens adhered to the eyes causing epithelial erosions.

THESE PHOTOGRAPHS SHOW A PATIENT SUFFERING FROM CORNEAL DISEASE ASSOCIATED WITH HERPES ZOSTER WITHOUT (LEFT) AND WITH (RIGHT) HER SCLERAL SHELL ON HER RIGHT EYE.

The tarsorrhaphy of the right eye was reversed, and a gas permeable scleral lens was fitted to vault the fibrovascular scar. The punctate keratitis resolved and best corrected vision returned to 20/40. After one year, the patient maintained a daily wearing time of 16 hours. This case illustrates how scleral contact lenses can be an effective alternative for optical and therapeutic treatment when standard ophthalmic treatment is inadequate.

FURTHER INDICATIONS FOR SCLERAL LENSES

Today, scleral lenses are used primarily to correct irregular astigmatism, lid abnormalities, prosthetic problems and corneal desiccation; however, they may also be indicated for other conditions.

Severe burns may require acute care that includes saline to prevent exposure keratitis, antibiotics to prevent bacterial infection and a protective shell to prevent symblepharon formation.

Scleral lenses can also be used to manage the pain associated with severe bullous keratopathy. Although the pain can often be managed with a hydrogel bandage lens and over-the-counter analgesics, a rigid scleral shell can provide adequate comfort and visual potential. Such physiologically compromised corneas must be monitored carefully for neovascularization and scarring, especially since a scleral lens can obscure such signs.

Severe dry eye secondary to Stevens-Johnson syndrome and keratoconjunctivitis sicca can be very debilitating. Scleral lenses can help maintain contact between the tears and the ocular surface, which increases vision and comfort. The shell also reduces tear evaporation and decreases the likelihood of symblepharon. Likewise, scleral lenses may be indicated for patients suffering from Bell's palsy, Graves ophthalmopathy, or space-occupying brain lesions leading to proptosis.

Patients with scarred, disfigured corneas may require scleral shells for prosthetic, cosmetic correction. PMMA scleral lenses can be ideal for this application and can be painted in exquisite detail to match a fellow eye.

Scleral contact lenses can provide good optical and therapeutic options for treating the previously mentioned eye problems plus many others, but they do require a significant commitment of both time and money by both the patient and the practitioner. CLS

Dr. Walline is a graduate student in physiological optics at The Ohio State University College of Optometry. Dr. Zadnik is an assistant professor at OSU.