Time-varying model useful for predicting myopic regression after LASIK

An interval-censored model efficiently predicted patients' risks of myopic regression after undergoing LASIK, a study by researchers in Taiwan found. Overall, average-risk eyes showed a 21% risk of such regression up to 6 months postop, the study authors noted.

Yun-I Chen and colleagues reviewed data for 615 eyes of 311 patients with at least 12 months follow-up after undergoing LASIK in 2003.

The researchers split the data into two groups, with 308 eyes included in the trained data set and 307 eyes in the validated data set. The interval-censored model used these data sets to predict the likelihood of myopic regression and to identify any demographic features or pre- and postoperative variables associated with regression, according to the study.

At 12 months minimum follow-up, 164 of the 615 eyes (26.7%) demonstrated myopic regression.

Investigators found that patients had a 21% risk of myopic regression up to 6 months postop. The regression risk increased rapidly within 1 month after LASIK, slowed between 1 month and 6 months postop, and then became steady after 6 months, "regardless of risk group," the authors reported.

"Significant predictors for myopia regression after LASIK included preoperative manifest spherical equivalent (P < .0001), mean preoperative central corneal curvature (P = .001), size of optic zone (P = .0043), undercorrection (P = .04) and age (P = .0734)," they said.

The authors deemed the model useful for predicting myopia regression and identifying factors associated with regression.

The study is published in the August issue of Investigative Ophthalmology and Visual Science.