What is Keratoconus
Keratoconus is a progressive eye condition that affects the structure of the cornea, which is the clear, dome-shaped front surface of the eye. In keratoconus, the cornea gradually thins and bulges outward in a cone-like shape, leading to visual distortion and changes in refractive error.
The exact cause of keratoconus is not fully understood, but it is believed to involve a combination of genetic and environmental factors. It typically begins during adolescence or early adulthood and can progress slowly over time.
Symptoms of keratoconus may include:
- Blurred or distorted vision: Vision may become progressively blurry and distorted, making it difficult to see clearly.
- Increased sensitivity to light: Many individuals with keratoconus experience increased sensitivity to light (photophobia) and glare.
- Frequent changes in eyeglass prescription: Due to the irregular shape of the cornea, the refractive error can change frequently, necessitating frequent changes in eyeglass prescription.
- Distorted or ghosting of images: Objects may appear distorted or have multiple images (ghosting) due to the irregular corneal shape.
- Poor night vision: Many people with keratoconus experience poor night vision, which can make driving or other nighttime activities challenging.
The diagnosis of keratoconus typically involves a comprehensive eye examination, including a detailed assessment of the cornea using various imaging techniques such as corneal topography and tomography.
Treatment options for keratoconus depend on the severity of the condition and may include:
- Eyeglasses or contact lenses: In the early stages, vision correction through eyeglasses or specialized contact lenses, such as rigid gas permeable (RGP) lenses or scleral lenses, may be sufficient to provide clear vision.
- Corneal cross-linking: This procedure involves applying riboflavin (vitamin B2) eye drops to the cornea and then exposing it to ultraviolet light. Cross-linking helps to strengthen the corneal tissue and slow down the progression of keratoconus.
- Intacs or corneal implants: These are small, clear, semi-circular devices inserted into the cornea to flatten the cone shape and improve vision.
- Corneal transplant: In advanced cases where vision cannot be adequately corrected with other methods, a corneal transplant (keratoplasty) may be recommended. This involves replacing the damaged cornea with a healthy donor cornea.
Read more about Keratoconus here:
What is Corneal Crosslinking
Corneal cross-linking (CXL) is a minimally invasive procedure used to treat progressive keratoconus and certain other corneal conditions. It aims to strengthen the cornea and halt or slow down the progression of the condition. The Glaukos iLink™ is the only FDA-approved corneal crosslinking treatment for patients with progressive keratoconus and corneal ectasia following refractive surgery.
During Glaukos iLink™, the cornea is first prepared by removing the outermost layer of the cornea, called the epithelium. This can be done through a mechanical method or by applying a medication that loosens the epithelial layer for easier removal.
Once the cornea is prepared, riboflavin eye drops, which contain vitamin B2, are applied to the cornea for 30 minutes. The Riboflavin containing Photrexa® Viscous (riboflavin 5’-phosphate in 20% dextran ophthalmic solution) and Photrexa® (riboflavin 5’-phosphate ophthalmic solution is absorbed into the collagen fibers of the cornea.
After applying the riboflavin drops, the cornea is then exposed to UV-A light for 30 minutes. This process activates the riboflavin molecules, causing them to create new cross-links or bonds within the collagen fibers of the cornea. These cross-links strengthen the cornea, increasing its rigidity and stability.
The entire procedure is typically performed in an outpatient setting, and the eye is numbed with local anesthesia. It usually takes just a little over 1 hour. Depending on the specific technique used, a device may be placed on the eye to deliver the UV-A light, or the patient may be positioned under a specialized UV light source.
Corneal cross-linking is intended to stabilize or slow down the progression of conditions like keratoconus, reducing the need for more invasive interventions such as corneal transplant in the future. It does not usually reverse the changes that have already occurred in the cornea or significantly improve vision on its own. However, it may help to prevent further deterioration of vision and preserve the integrity of the cornea.
After the procedure, patients may experience temporary discomfort, light sensitivity, and blurred vision, which usually subside within a few days to weeks. Eye drops and medications are typically prescribed to aid in healing and manage any post-operative symptoms.
The goal of crosslinking is to
· Create new corneal collagen cross-links
· Shortening and thickening of the collagen fibrils
· Stiffen of the cornea
Is iLink™ Covered by Insurance?
The medical necessity of iLink™ has become widely recognized. As a result, commercial insurance coverage for iLink™ is now over 95% in the United States for covered lives. Only iLink™ is approved by the FDA and is covered by insurance. Typically, non–FDA-approved procedures are not covered by insurance and have not been proven safe and effective. For patients without insurance, cash-pay options are also available.
View videos about Corneal Crosslinking here:
This article was originally written on 7/3/2020 by Angelique Pillar, MD and updated on 5/28/23.