Intracorneal ring segments, or prescription inserts, are a non-laser procedure with FDA approval for use in patients with low amounts of myopia (-1.00 to -3.00 diopters of myopia with up to +1.00 diopters of astigmatism). They are intended to correct low amounts of nearsightedness but not astigmatism.
The procedure involves the placement of two plastic segments within the non-seeing periphery of the cornea. These segments flatten the central cornea without removing tissue to better focus light. The segments are made of the same material that's been implanted in human eyes after cataract surgery for nearly 50 years, called PMMA (polymethylmethacrylate). Inserts have the advantage of removability or exchangeability for different sized segments, and maintaining a more natural corneal shape. The more natural corneal shape may provide better vision than LASIK.
One emerging use of prescription inserts is for an eye disease called keratoconus, a condition where the corneal surface is irregular and causes poor vision.
What Happens During the Procedure?
Typically, topical anesthesia is used in conjunction with a mild oral sedative.
The procedure takes approximately fifteen minutes per eye.
First, a single small opening is made in the cornea at the 12:00 position. Then a centering guide is applied for one to two minutes, to stabilize the eye. During this time, two semicircular tunnels are made by separating corneal stroma. The inserts will be inserted in these tunnels. Finally, the insert segments are placed and the opening is closed.
Who's a Good Candidate?
Prescription inserts are ideal for patients:
You should check with you eye doctor to determine if you are a good candidate.