Laser thermal keratoplasty (LTK) is a procedure that is very similar to, and been essentially replaced by, conductive keratoplasty (CK). The primary difference is that LTK uses laser energy to reshape the cornea, whereas CK (also called NearVision CK) uses radiofrequency (RF) energy.
Both procedures involve applying energy to discreet points in the peripheral cornea, arranged in a circular pattern. As these treated areas heal, they cause the curvature of the central cornea to steepen. This increase in corneal curvature corrects mild amounts of hyperopia (farsightedness) and can also improve near vision in individuals over age 40 who need reading glasses due to presbyopia.
LTK was approved by the U.S. Food and Drug Administration (FDA) in June 2000 for the temporary reduction of +0.75 to +2.50 diopters of hyperopia (farsightedness) with up to 0.75 diopters of astigmatism in individuals age 40 and older.
The procedure has essentially been replaced in the U.S. by NearVision CK, which appears to have less loss of effect (regression) and may deliver more consistent outcomes.