Thermal Keratoplasty for Farsightedness

Topic Overview

Thermal keratoplasty is a type of refractive surgery that uses heat to change the shape of the eye's cornea. The surgeon uses a device to shrink the collagen fibers in the cornea. This causes a lasting scar on the cornea. Though the treatment is not effective for severe farsightedness (hyperopia), it has been shown to correct mild to moderate farsightedness. Thermal keratoplasty can be applied through a laser (noncontact) or probes (contact).

Noncontact technique

Laser thermokeratoplasty (LTK) involves applying pulses of laser light in ring formation to the cornea. This heats the collagen and changes the shape of the cornea. Actual treatment time is only a few seconds for each eye. LTK has been approved for people over 40 years of age who have mild hyperopia of 2.5 diopters or less. There is some discomfort after the procedure, including expected initial overcorrection of vision.

Contact technique

Conductive keratoplasty (CK) is a relatively new technique that can treat mild to moderate farsightedness. A contact probe delivers radiofrequency energy to multiple locations on the cornea, shrinking the collagen and steepening the central cornea. Treatment takes less than 1 minute for each eye.

Disadvantages of the procedure include an initial overcorrection, inability to treat astigmatism, scarring of the cornea, and a possibility of inducing astigmatism. Also, the correction may not last, so you may need to have the procedure again.