Conductive keratoplasty: temporary approach for treating hyperopia

Conductive keratoplasty corrects mild-to-moderate hyperopia, but the results may not be permanent, reported Jason Erlich, MD. He and colleagues conducted a study to determine the long-term results of conductive keratoplasty for the treatment of hyperopia.

Twenty-five eyes of 14 patients (mean age, 55 years) were enrolled in 1999. The visual results at 1 year were good, with 92% of patients have 20/40 or better. Eighteen of the patients completed the 2-year follow-up examination. Of these, 64% had 20/20 uncorrected visual acuity, and 95% had 20/40 or better uncorrected visual acuity. The preoperative mean spherical equivalent was 1.64 D and at 24 months it was 0.48 D.

"This represented a 29% regression from the intended correction," said Dr. Erlich, of Stanford University School of Medicine, Stanford, CA.

Sixteen eyes of nine patients completed the 6-year follow-up. They had been followed for a mean of 73.6 months (range, 44 to 90 months), which is the longest follow-up worldwide, Dr. Erlich pointed out.

The investigators observed a slow linear regression of the conductive keratoplasty effect to +1.43, which was almost to the baseline value of +1.49, he reported.

Regarding safety, 21% of patients had 20/20 or better uncorrected visual acuity, 42% had 20/30 or better, 58% had 20/40 or worse vision. Four of the patients developed cataract. All of the eyes were refracted to at least 20/40 and there was no induced cylinder.

The question that arose in connection with this result was: Does this represent hyperopic regression?

"I can't fully answer that question, because most of the eyes in the study were treated," Dr. Erlich said. "There was one untreated eye that was followed that had a preoperative spherical equivalent of +1.5, and at the 7-year follow-up the spherical equivalent was +2.0."

So the regression in these patients seems to be not just the result of hyperopic regression only, he said.

Dr. Erlich pointed out that this was a small study, no Light Touch technique was used, and all procedures were performed by one surgeon in one center.

"Conductive keratoplasty for hyperopia is safe and initially effective," Dr. Erlich said. "However, there is significant regression toward the baseline value. The results may not be permanent and patients should be advised of this before the procedure is performed."