There are currently multiple options before corneal transplantation might be required. They range from:
- Soft contact lenses
- Rigid gas permeable contact lenses (when fitted properly this is the most successful option).
- Rigid gas permeable lenses piggybacked on soft disposable contact lenses
- Mini-scleral contact lenses
- Corneal Cross Linking with Riboflavin (C3R)
- Intracorneal Ring implantation (Corneal Ring)
- Re-prescribing glasses, soft contact lenses or rigid gas permeable contact lenses after Corneal ring implantation /corneal cross linking with riboflavin.
Rigid Gas Permeable (RGP) contact lenses are often the treatment of choice for moderate to severe KC. The hard surface of the lenses provides the proper curvature for light to enter the eye and focus on the retina, while the gas permeable nature provides sufficient oxygen for the cornea. Additionally, a number of specialized contact lenses developed specifically for keratoconus are currently on the market including: FlexiK, Rose-K, and others. These specialized lenses use computer-modeling to produce a lens in which the inside curvature is specially vaulted to fit over the corneal cone, while still providing an optically efficient curvature on the outside of the lens. The contact lens fitter can then further customize the design of the lens for a particular patient by adjusting size, rim design, prescription, and the degree of curvature.
How to use contact lenses in the Indian scenario?
We agree that there are specific challenges for wearer of RGP contact lenses in our country. One of the key problems is that of making sure that lenses do not fall out easily — or more correctly, to keep lenses from getting lost if they do fall out. This can often be accomplished with sports goggles. Another problem very common to our country is the dusty or windy conditions. Dust can easily get caught under a contact lens, producing a rather painful experience until the lens can be removed and cleaned. For this problem, sunglasses containing side panels (the kind used by two wheeler riders) can be used in daylight condition, while goggles can be used in low-light conditions. This is also very useful for people in urban areas who travel by buses and local trains.
Finally, eye drop products that lubricate the eyes (a large number are available in
the Indian market – for occasional use any reputed brand is adequate) can be used to quickly clear the lens while it is still in the eye so that it does not need to be removed in the event that dust becomes trapped underneath.
Scleral lenses provide the next level of contact lens options for keratoconus as they are much larger and actually fit over the sclera (white portion) of the eye. The lenses tend to be more comfortable for patients with severe KC or with sensitivity to smaller RGP lenses. This revolutionary technology has helped some patients at Keratoconus Center of Clear Vision Eye Center, delay corneal surgery for up to 10 years.
C3-R has been proven to strengthen the weak corneal structure.This method works by increasing collagen cross linking, which arethe natural anchors within the cornea. These anchors are responsible for preventing the cornea from bulging out and becoming steep and irregular, consequence of advanced keratoconus.
Dr Agrawal has successfully performed corneal cross linking on a number of patients from across the country and abroad. He says, “Corneal Cross Linking is the first real treatment for my keratoconus patients. The achievement of stabilization is a dramatic event in the life of these patients with a disease that is otherwise progressive and affects both eyes.”
The 30-minute non-invasive C3-R treatment is performed in the doctor’s office. During the treatment, custom-made riboflavin eye drops are applied to the cornea, which is then activated by ultraviolet light. This amazingly simple process has been shown in laboratory and clinical studies to increase the amount of collagen cross-linking in the cornea and strengthen the cornea. In published European studies, such treatments were proven safe and effective in patients (more details on www.clearvision.org.in)
These consist of two small half-rings which are implanted on either side of the cornea. The idea is that the spring action of the implant helps to reshape the cornea to compensate for the bulge in the middle.
Since Intracorneal rings are a more invasive approach than contact lenses, they are generally suggested for patients who are no longer able to see well with contact lenses or who are no longer able to tolerate contacts due to discomfort. This technique has been in use since a decade and has helped several patients return to contact lenses.
For patients whose KC has become severe to the point of no longer being able to see well with contacts or implants, corneal transplantation is generally the ultimate treatment. In a transplant the
weakened central portion of the patient’s cornea is removed and the donor cornea is stitched into place. Corneal transplants are often the most successful type of transplant surgery. Corneal transplantation is among the most successful of organ transplant surgeries. According to the literature, over 90% of the corneal grafts are successful with some studies reporting 97% to 99% success rates at 5 and 10 years. Transplantation does not provide a complete solution, however, as a significant number of transplant patients will require RGP contacts after surgery. In a small number of cases, keratoconus has been found to occur in the newly transplanted cornea. Even in corneal transplantation there are a number of modern adaptations, offered at Clear Vision Eye Center, like deep lamellar corneal (keratoplasty) transplantation (DALK) that make the surgical results more predictable and better than ever before. ( more details available on www.clearvision.org.in )