RADIAL KERATOTOMY

(RK)

WHAT IS RADIAL KERATOTOMY?

Radial keratotomy (RK) was a surgery that gained popularity in the 1980s, using manual incisions in the cornea to correct a person's glasses prescription by changing the shape of the cornea.

The surgery was eventually discontinued due to a constantly changing prescription and vision that fluctuated throughout the day. Changes in vision are common in about 43% of post-RK eyes according to the Prospective Evaluation of Radial Keratotomy (PERK) study.

These patients now are unable to achieve the excellent vision they once had, even with glasses. Symptoms can be fluctuating vision, starbursts, double vision, and decreased contrast sensitivity.

WHY CAN'T THOSE WITH RADIAL KERATOTOMY SEE WELL WITH GLASSES?

An image results from rays of light going through the eye. In patients with radial keratotomy, once light rays go through the glasses, they still hit the irregular incisions on the cornea and bend in many different directions, resulting in poor vision.

The process of RK involves making incisions in the cornea to try and flatten the cornea to correct vision. The incisions result in a weaker corneal structure. The pressure behind the cornea (intraocular pressure) changes throughout the day and pressures changes can push on this weaker cornea, causing it to change shape and thus, prescription throughout the day. Glasses with one prescription cannot correct for the constant prescription change of these patients.

The flattened cornea also means that traditional soft contact lenses have a difficult time fitting on the eye as the eye is now a different shape than prior to surgery.

The best option for optimal vision in patients with radial keratotomy is a rigid lens (rigid gas permeable, hybrid, or scleral lens).

WHAT CONTACT LENS OPTIONS ARE THERE FOR THOSE WITH RADIAL KERATOTOMY ?

Contact lenses are a great option for those with radial keratotomy because the tear film between your cornea and the lens can mask irregularities and create a "new" corneal surface with the lens that helps you see more clearly.

1.) Scleral Lenses

Scleral lenses are large gas-permeable (rigid) lenses that are able to vault over even the flattest of corneas with radial keratotomy incisions. These lenses are filled with a sterile saline solution each morning before insertion and the saline stays on your eyes all day.

The lenses rest on the white portion of the eye (the sclera) instead of on the cornea so there is not the risk of corneal scarring or discomfort from a poor-fitting lens.

These are an ideal option for those with radial keratotomy because the cornea is so flat after the procedure, other lenses may be uncomfortable or have difficulty centering on the eye.

2.) Rigid Gas Permeable Lenses (RGP)

Rigid gas permeable lenses are smaller gas-permeable lenses that are easy to insert and remove and can provide excellent vision. They move slightly with blinks and allow maximum oxygen to get to the eye.

3.) Hybrid Contact Lenses

Hybrid contact lenses are comprised of a rigid gas permeable lens in the center and a soft contact lens "skirt" surrounding the lens. This can aide in helping the lens center and making them more comfortable.