Q: I have keratoconus when should I consider scleral lenses?
A: Keratoconus is a challenging disease. The usual management strategies include eyeglasses as long as functional vision can be obtained. Once vision is not functional with eyeglasses contact lenses, usually rigid gas permeable corneal contact lenses, are prescribed. Many patients with keratoconus function well life-long with corneal contact lenses. However, some patients will develop intolerance to their contact lenses based on discomfort with corneal contact lenses limiting their wear during the day or unstable corneal contact lenses that make lens wear unpredictable. Some patients with keratoconus will have poorly positioned corneal contact lenses that reduce comfort and perhaps vision. In the past these patients went on to corneal transplant surgery. Gas permeable scleral contact lenses are an alternative to corneal transplant surgery. Prior to considering surgery a trial with a gas permeable scleral lens is worthwhile as it will identify those patients who can avoid or delay corneal transplant surgery.
Q: Why do scleral lenses work in keratoconus?
A: Think of the cornea in keratoconus as a very bumpy surface. When we try to put a contact lens on this surface it floats all around trying to “seat itself”. In some cases the lens just keeps popping out because it can’t find a secure resting spot and in other cases the lens will keep rubbing on the same spot causing severe irritation and corneal abrasions. All lenses that rest on the cornea will be limited by the corneal shape.
A scleral lens is supported by the white tissue of the eye (the sclera) and the lens “vaults” over the corneal surface. It does not touch the cornea so the amount of distortion of the cornea is not important and since it does not touch the cornea there is no rubbing on the corneal surface. A scleral lens has the potential to dramatically improve comfort in those patients with keratoconus who have become contact lens intolerant.
Q: My doctor says my keratoconus is mild yet I can’t seem to tolerate contact lenses and the vision with my glasses is getting worse. My doctor has tried everything. I asked my doctor about scleral lenses but he said they were only for more severe cases of keratoconus. Will scleral lenses work for me?
A: The use of scleral lenses in keratoconus is not related to the severity of the disease. Patients with mild keratoconus can be fitted with gas permeable scleral lenses.
Q: My keratoconus is very advanced. I see well with my contact lenses but one lens pops out 5 or 6 times every day and I can only wear my other lens for a few hours everyday because it hurts. My doctor says this is the best fit I can get. Can a scleral lens help me?
A: The use of scleral lenses in keratoconus is not related to the severity of the disease. Patients with advanced keratoconus can be fitted with gas permeable scleral contact lenses.
Q: What is the vision like with gas permeable scleral contact lenses?
A: Since a gas permeable scleral lens is a hard lens the vision is usually similar to what we can obtain with a hard contact lens. There are two notable exceptions. The first is in those patients with an unstable contact lens. Because a scleral lens centers better and is more stable the vision may be better with a scleral lens than with a corneal lens. The other exception is found in some patients with keratoconus where visual acuity is not good unless the contact lens is flattening the corneal surface while the lens is worn.
In these patients vision may not be as good with a scleral lens because the scleral lens does not touch the corneal surface.
Q: I have Stevens-Johnson syndrome (SJS) and am very light sensitive. My vision is good compared to others with Stevens-Johnson syndrome but my eyes hurt all the time. I asked my doctor about scleral lenses and she thought they would do more harm than good.
A: Your doctor’s response is not unusual, doctors often associate scleral contact lenses with the poorly tolerated scleral lenses of the 1940’s, 50’s, and 60’s. The old scleral lenses often did do more harm in that not enough oxygen could get to the cornea. It was not the size of the lens that was the problem but the lack of oxygen through the material. Gas permeable scleral lenses today are made of highly oxygen permeable materials so that the benefits of scleral lens wear greatly outweigh the risks. Patients wearing scleral lenses need to be followed closely to monitor for any adverse effects of lens wear.
In patients with ocular disease following SJS, a scleral lens has the potential to dramatically improve the corneal environment. Scleral lenses create a reservoir of fluid that bathes the corneal surface while the lens is worn. This often reduces the pain and light sensitivity that can be debilitating for patients with SJS.
Q: Do scleral lenses help with vision in patients with SJS?
A: Yes and no. It depends on the degree of corneal scarring centrally and the amount of corneal irregularity. In some patients the corneal scarring is too severe so the lens may dramatically reduce the pain and light sensitivity but not have much impact on vision. In other patients the vision may be greatly improved because the scleral lens neutralizes the corneal irregularity while the lens is worn.
Q: Can I sleep with scleral lenses?
A: Generally no. While scleral lenses are highly oxygen permeable there is an increased risk for infection when wearing any contact lens overnight.
Q: Do scleral lenses have any risks?
A: Absolutely. All contact lens wearers (soft lens wearers, corneal lens wearers, and scleral lens wearers) have an increased risk for infection and long-term complications relating to the amount of oxygen available to the cornea through the contact lens. Scleral lenses don’t intrinsically have a higher risk; however, scleral lenses are usually used on eyes with higher risks based on their eye disease.
Q: What are the differences in the gas permeable scleral contact lenses that are available today?
A: There are two types of gas permeable scleral lenses available today. For the most part the lens materials are very similar. The lens designs however are different.
Fenestrated scleral lenses have actual holes in the lenses to allow tears to move in and out of the lens compartment to prevent lens suction and as an added source of oxygen. This sometimes allows air to get in too which can be a problem. Fenestrated lenses are the easiest for patients to put in but are often the hardest to fit.
Nonfenestrated scleral lenses allow tears to move in and out of the lens compartment by adjusting the fit of the support portion of the lens or by adding channels or tunnels into the lens surface. This makes the lens a little harder to insert but has the advantage of excluding any air bubbles in the lens reservoir.
Q: How does your scleral lens design differ from Dr. Rosenthal’s lens? Why is there such a difference in the costs?
A: Both lenses are nonfenestrated lenses. It is the design of the lenses that is different. There will be some patients that are better fit with a lens design from Parkway Sclerals and some patients who will be better fit with Dr. Rosenthal’s design. The majority of patients can be fitted successfully with either design.
As a private practice, Parkway Sclerals has a lower overhead and can better control the costs of fitting scleral lenses than larger nonprofit research foundations. Doctor Cotter has made it a priority to ensure scleral lenses are affordable for those who can benefit from their use.