# Evaluating the Rate and Causes of Non-candidacy After Laser-Assisted in Situ Keratomileusis (LASIK) Screening

## TL;DR

This study examines why most people who get evaluated for LASIK eye surgery are not eligible, finding that reasons vary by age group.

## Contribution

The study provides updated insights into LASIK non-candidacy rates and reasons, highlighting age-related differences in corneal and refractive factors.

## Key findings

- The overall LASIK non-candidacy rate was 69.4%, with presbyopia and abnormal topography being the main causes.
- Younger patients (<45) were often excluded due to corneal thinning and severe myopia, while older patients (≥45) were excluded due to presbyopia.
- Diagnostic advancements and surgical alternatives have increased the non-candidacy rate but improved patient outcomes.

## Abstract

Purpose

To provide an updated characterization of the reasons for laser-assisted in situ keratomileusis (LASIK) non-candidacy.

Methods

A retrospective chart review was conducted on 648 patients (648 right eyes) who presented for LASIK evaluation at a refractive surgery center in Draper, UT, between November 2022 and April 2023. Age, spherical equivalent (SEQ), and keratometry measurements were compared between LASIK candidates and non-candidates. The overall rate of non-candidacy and reasons for exclusion were documented. Subgroup analyses were performed based on age groups, stratifying patients into two cohorts: patients younger than 45 years and those 45 years or older.

Results

The overall LASIK non-candidacy rate was 69.4%, primarily due to emmetropic presbyopia (36.9%), abnormal topography (31.3%), and hyperopic presbyopia (25.6%). Among patients < 45 years, non-candidacy was often due to abnormal topography (43.5%), corneal thinning (24.5%), and severe myopia (20.7%). Compared to LASIK candidates < 45 years, non-candidates had thinner corneas (548.8 ± 29.0 vs 526.4 ± 33.6 µm; P < 0.001), and steeper corneas, including K1 (42.7 ± 1.6 vs 43.3 ± 1.5 D; P = 0.002) and K2 (43.9 ± 1.6 vs 44.7 ± 1.7 D; P < 0.001). In contrast, for patients ≥ 45, presbyopia (emmetropia: 74.2% and hyperopia: 51.6%) was the leading barrier to qualifying for LASIK. Non-candidates in this cohort showed higher mean age (P = 0.02) and had less myopia (−0.71 ± 3.03 vs −3.40 ± 2.12 D; P < 0.001) compared to their eligible counterparts.

Conclusion

LASIK remains one of the most thoroughly evaluated refractive procedures, with a proven track record of long-term safety, efficacy, and high patient satisfaction. LASIK non-candidacy was found to be influenced by demographics, with distinct corneal patterns across each subgroup. Patients younger than 45 years were primarily excluded due to abnormal topography, corneal thinning, and severe myopia, while patients 45 and older were more often excluded due to presbyopia, specifically emmetropia and hyperopia. The high non-candidacy rate not only reflects the rigorous screening criteria but also the increased sensitivity of diagnostic devices and the expanding surgical alternatives, such as intraocular lenses with advanced optics for multifocal correction. This allows more patients to achieve greater visual satisfaction than was possible two to three decades ago.