We shared with you previously that Today’s Vision Sugarland has had success in fitting scleral contact lenses, which are large, rigid contact lenses that rest on the sclera, or white part of the eye, rather than the cornea. Scleral lenses are very helpful for patients who have irregular corneas and cannot wear soft or hard contact lenses that rest on the cornea.
We have patients who have a condition called keratoconus, which means their corneas are cone-shaped. To correct keratoconus, there are devices called intrastromal rings which are implanted into the cornea. Made from PMMA, the clear plastic used in the original rigid contact lenses, they were approved by the FDA in 2004 for correcting keratoconus.
These patients cannot have a contact lens placed over their cornea, putting pressure on the intrastromal rings. Yet some patients wish to wear contact lenses. Scleral lenses are their best option. However, fitting these patients present significant challenges because there can be complications related to the intrastromal rings.
We have several patients in our practice with intrastromal corneal ring segments who we have fitted with scleral contact lenses.
The first patient is a 52-year-old Hispanic man who has been our patient since 2003. He was diagnosed with keratoconus by his ophthalmologist in Chile. He was able to wear rigid gas permeable contact lenses for some time.
By 2013, his keratoconus had gotten worse, and the rigid gas permeable lenses failed to give him the comfort and vision he needed for his job as nurse. He received IntacsⓇ intrastromal rings in his right eye. By early 2014, his keratoconus had been corrected well enough to be ready to be fitted with scleral lenses.
He initially liked the scleral lenses, but over the next year he struggled with fogging issues that required frequent removal and rinsing. In 2015, we refit the patient in a slightly larger lens with more clearance to protect the cornea over the area of the intrastromal rings. We also reduced the clearance around the edges so as not to encourage influx of mucus and other tear debris under the lens, which makes fogging worse.
The patient is now comfortably wearing scleral lenses over the IntacsⓇ. As this case demonstrates, intrastromal corneal rings do not always result in a permanent flattening of the central cornea and regression is possible. The next time we see this patient, I anticipate utilizing larger lenses with slightly more clearance. The goal is to not put any pressure over the rings that would encourage stress.
The second patient is a 33-year-old Asian gentleman with very advanced keratoconus. He came to our office with a history of scleral lens wear but remained uncomfortable in his lenses with reduced wearing time. This affected his occupation as a radiology technician, which required long hours at work.
He had received IntacsⓇ in both eyes previously, but due to complications, three out of the four segments had been removed.
We first fit the patient in a commonly used brand of scleral lenses. After several modifications to the lens design, he was able to get 10-12 hours of wear in relative comfort. Lenses were first made smaller, then larger. Care had to be taken not to cause bubbles under the lens, which occurred on several occasions.
The best fit was obtained using larger scleral lenses, which provided great vision and the best comfort. Unfortunately, however, despite the well-fitting lenses, the left eye required a corneal transplant. Intrastromal rings do not always halt the progression of keratoconus.
As these two cases show, corneal stability is not always achieved with intrastromal rings. Care must be taken when fitting these patients with scleral lenses to provide adequate clearance over the cornea so as not to affect the rings. We monitor these cases closely, at least every 6 months. By helping patients who have these challenging visual conditions, we are proud to greatly improve the quality of life of these patients.