Hyperopic LASIK yields favorable long-term outcomes to obtain emmetropia

Prospectively collected data from 45 eyes that underwent hyperopic LASIK using a proprietary excimer laser were analyzed. After a mean follow-up of 5.3 years, about three-fourths of the eyes had a spherical equivalent within 1.0 D of the emmetropic target.

Key Points

Dr. Jain presented the results of analyses of prospectively collected data from 45 eyes of 27 patients treated with the excimer laser for hyperopia (+0.75 to +6.25 D). Mean follow-up was 5.3 years (range, 3 to 8 years), and only a mild regression effect was noted after 1 year in the overall cohort (mean, +0.30 D). When the eyes were divided into three groups based on the amount of preoperative hyperopia, eyes with high hyperopia (>+4.00 D, 15 eyes) experienced significantly more regression than eyes with low (<+2.00 D, 17 eyes) and moderate (+2.00 to +4.00 D, 13 eyes) hyperopia.

A need for long-term data

"The . . . system [used in this study] is one of the most commonly used platforms in the United States, but the longest-term outcomes reported for its use in hyperopic LASIK are based on no more than 2 years of follow-up. We conducted this study to be able to answer our patients who were asking about the long-term stability of the treatment we were offering."

He added: "The results from our analyses are similar to those in previously published studies. We now plan to continue to follow these patients and will be evaluating their 10-year results."

Edward E. Manche, MD, director of cornea and refractive surgery, Stanford Eye Center, Stanford University, performed all of the surgeries. The treatment nomogram factored in a 10% increase in the programmed hyperopic treatment, which was based on the cycloplegic refraction, to compensate for the tendency for undercorrection with the laser platform. The treatment goal was emmetropia in all eyes except in one patient who wanted monovision. The latter individual later underwent enhancement to emmetropia.

Mean preoperative spherical equivalent (SE) refraction was 2.70 D for all eyes, and the last-visit data showed a tendency for undercorrection with a mean SE of 0.50 D. In the three subgroups representing the different levels of hyperopia, mean postop SE refraction ranged from 0.44 to 0.59 D.

Calculating predictability

Predictability was calculated by dividing the achieved SE by the attempted refractive change. The mean for the entire group was 0.76 D, and it ranged from 0.67 D to 0.89 D in the three subgroups. The graph of achieved versus attempted SE showed a moderate correlation between the two (R2 = 0.72 D).

"The predictability was best in the low hyperopia group and declined with increasing amount of hyperopia, but there were no statistically significant differences among the three hyperopia groups," Dr. Jain said.

Between 70% and 80% of patients across the low, moderate, and high hyperopia groups had an achieved SE at last visit within 1 D of emmetropia, and about 40% to 45% were within 0.5 D of their target. At last follow-up, uncorrected visual acuity (UCVA) was 20/20 or better in about one-third of eyes. Slightly more than half had UCVA of 20/25 or better, whereas more than 80% had UCVA of 20/40 or better.

Visual outcomes were best in eyes treated for low hyperopia, and they decreased with increasing levels of treatment. In the high hyperopia group, about 50% of eyes had UCVA of 20/40 or better at last visit compared with almost 100% in the low hyperopia group.

Between the 1-year and last-available visit, the mean hyperopic shift averaged 0.18 D in the low hyperopia group, 0.31 D in the moderate group, and 0.44 D in the high group.

"Our experience is similar to previously reported studies in finding that the UCVA outcomes are best in eyes treated for the lowest amount of hyperopia. However, the amount of regression noted in our study is a little less than reported by the others. The proportion of eyes with an SE at last follow-up within 1 D of emmetropia is similar across the various studies," Dr. Jain said.OT