C3R Procedure for Keratoconus

C3R Procedure for Keratoconus
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What is Keratoconus?

Keratoconus is a condition of the cornea that is characterized by a protruding bulge. The cornea is unusually thin and not structurally sound enough to maintain a round shape. As the cornea expands, vision is affected. Blurriness and sensitivity to light are common symptoms of keratoconus.

Keratoconus is a progressive condition that starts in the late teen years or early twenties. The round shape of the cornea becomes cone shaped over a period of 10 to 20 years. There are several treatment options that can slow the progression of keratoconus. Individuals usually need contact lens, intracorneal rings, or corneal transplants to correct vision problems associated with keratoconus.

C3R - Corneal Collagen Crosslinking with Riboflavin

One of the newer and promising treatment options for keratoconus is corneal collagen crosslinking with riboflavin, or C3R. C3R addresses the root cause of keratoconus, namely the instability of the corneal tissue. The cornea consists of collagen, which is made of proteins. In individuals with keratoconus, the linkages between the proteins are not sufficient enough to hold the round shape of the cornea. C3R is designed to increase the number of cross-linkages between the collagen proteins and prevent the cornea from bulging out any further.

The C3R Procedure

During the C3R procedure, eye drops containing riboflavin are introduced to the cornea. After the cornea adequately absorbs the eye drops, ultraviolet light is placed over the eye. A chemical reaction between the riboflavin and ultraviolet light leads to the formation of crosslinks in the corneal tissue. As a result, the cornea is much more stable and resistant to bulging.

The C3R procedure for keratoconus lasts about an hour. After the procedure, a soft contact lens is worn to protect the cornea. Eye drops are also required for several weeks after the procedure to protect the cornea.

Candidates for C3R

Not everyone with keratoconus can benefit from corneal collagen crosslinking with riboflavin. The C3R procedure for keratoconus is for individuals that have mild to moderate bulging and don’t have any scarring on the cornea. These individuals can receive treatment to prevent further bulging. Individuals with advanced keratoconus or have scarred corneas usually can’t benefit from the procedure. They usually require a corneal transplant.

Advantages of C3R

The biggest advantage of C3R over other treatment options is that it slows, and in some cases, stops the progression of keratoconus. It is a non-invasive, out-patient procedure that stabilizes the cornea by increasing the number of crosslinks in the collagen. No other treatment option available addresses this. If the procedure is done in the early stages of the condition, the use of rigid gas permeable contact lenses can be avoided. This type of contact lens is usually prescribed to correct vision problems associated with keratoconus. In addition, since C3R halts the bulging of the cornea, scarring of the cornea becomes less likely with age. This reduces the chances of requiring a cornea transplant later in life.

Reference

1. “What is Keratoconus?” National Keratoconus Foundation https://www.nkcf.org/en/about-keratoconus.html.

2. “Crosslinking.” National Keratoconus Foundation. https://www.nkcf.org/treatment-options/corneal-crosslinking.html.

3. “Corneal Collagen Crosslinking with Riboflavin.” Ophthalmology and Laser Eye Treatment https://www.eyecarelondon.com/html/c3r.html