Youth does not predict adverse outcomes in LASIK

The study includes data from 1,718 eyes of 878 patients ages 18 to 21 years old, 3,407 eyes of 1,734 patients between 22 and 25 years of age, and 27,840 eyes of patients aged 26 years and older who were treated at 14 corporate laser centers across Europe (Optical Express). All eyes underwent LASIK using a wavefront-guided platform (Abbott Medical Optics/VISX) and a femtosecond laser for flap creation.

Results from a 3-month postoperative visit showed no safety concerns so far among patients ages 18 to 25 years old. For their collective 5,125 eyes, there were no cases of early ectasia and 99.7% were within 1 line of their preoperative best-corrected visual acuity (BCVA), Dr. Vukich said.

The importance of careful patient selection for avoiding post-LASIK ectasia is well-recognized and is the foundation for investigations attempting to identify risk factors for patient exclusion.

Risk score

In an ectasia risk score published by Randleman et al. (Ophthalmology 2008;115:37-50), young age was identified as an independently predicting ectasia risk. According to the risk scoring method established by the authors, point values (0 to 4) are assigned to patients based on five clinical features: age, residual stromal bed thickness, topography pattern, preoperative corneal thickness, and preoperative MRSE. Risk category is determined by the cumulative score.

For age, patients receive 3 points for being 18 to 21 years old, 2 points if they are 22 to 25 years old, and 1 point if aged 26 to 29 years old.

"Patients who are 21 years of age or younger with all other indices normal have a cumulative score of '3' and are categorized as being at moderate risk for developing post-LASIK ectasia in this system," Dr. Vukich said. "According to Randleman et al., surgeons should proceed with caution in performing LASIK in these patients.

"This determination seems at odds with our common sense analysis that considers all patients who have had LASIK were young at one time," he added.

In the study Dr. Vukich presented, patients were deemed eligible for the procedure if they had normal topography, refractive stability (SE change ≤0.5 D within the past year), and calculated residual stromal bed thickness >250 μm.

"Although the eyes in the youngest age group account for only a minority of the overall population, they still represent an appreciable percentage of those treated and who might otherwise be turned away from LASIK based solely on age," Dr. Vukich said.

No differences found

Analysis of refractive data showed a normal distribution of preoperative sphere within the overall population and no clinically relevant differences in subgroup analyses with patients stratified by age. The results were similar for cylinder.

"Although mean sphere was lower in the youngest patients and the difference between age groups was statistically significant due to the very large sample sizes, it was not dramatically different from a clinical perspective and the younger patients were just as likely to be treated for higher levels of myopia as their older counterparts," Dr. Vukich said.

Outcome data from the 3-month postoperative visit showed that the youngest patients and those ages 22 to 25 years old had better uncorrected visual acuity (UCVA) outcomes than the oldest cohort, with the percentages of patients achieving Snellen UCVA of 20/20, 20/25, and 20/30 all being higher in the subgroups aged 18 to 21 years old and 22 to 25 years old compared with those aged 26 and older.

In addition, the youngest patients were more likely to gain BCVA and less likely to lose 1 or more lines of BCVA.

FYI

John A. Vukich, MD
E-mail: javukich@gmail.com

Dr. Vukich is a consultant for Abbott Medical Optics and Optical Express.