Radial thermokeratoplasty for the correction of hyperopia.

Hyperopic thermokeratoplasty involves making controlled thermal burns in the corneal stroma in a radial pattern up to a premarked clear zone. It steepens the central cornea and reduces the hyperopia. A series of 117 radial thermokeratoplasty eyes done in the Soviet Union were analyzed. Mean preoperative hyperopia of +5.27 diopters (range = +0.50 to +17.00 D) was reduced at 12 months after surgery by a mean of -3.48 D, resulting in a mean postoperative spherical equivalent of +1.84 D. Average correction was 70.8%. Forty percent of eyes were corrected to less than 1.00 D residual refractive error; however, 58% were undercorrected by 1.00 D or more. The proportion of eyes seeing 20/40 or better unaided increased from 10% preoperatively to 52% by 3 months after surgery and remained at 53% at 12 months after surgery. Overall refractive stability was demonstrated during the 1st postoperative year. Stepwise regression showed that none of the preoperative or surgical factors significantly predicted outcome when all eyes were evaluated.