Visual And Refractive Predictability Of Automated Ray-Tracing Lasik Using A Modified Cylinder Protocol: A Prospective Study

To evaluate the outcomes of ray-tracing–guided LASIK (WaveLight Plus) in a Latin American population using a modified protocol with a systematic 10% reduction of the algorithm-calculated cylinder.

A prospective, interventional study

This prospective series included 50 eyes (25 patients) undergoing ray-tracing–guided LASIK (WaveLight Plus). The algorithm-calculated cylinder was manually reduced by 10% to address potential overcorrection. At 3 months, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, and Alpins vector analysis were evaluated. Secondary outcomes included higher-order aberrations (HOAs) and patient satisfaction.

At 3 months, 100% of eyes achieved a UDVA of 20/20 or better, and 80% achieved 20/16 or better. The manifest refraction spherical equivalent was 0.00 ± 0.14D, with 100% within ± 0.50 D. For astigmatism, 100% of eyes were within ± 0.25 D of intended correction. Alpins analysis yielded a Correction Index (CI) of 1.01 (slope = 1.01; R2 = 1.00), effectively neutralizing the previously reported overcorrection trend (CI: 1.12). No eyes lost lines of CDVA (safety index: 1.23). Spherical aberration showed a non-significant reduction (P = .323), while total HOAs increased slightly (P = .037). Satisfaction was high.

Ray-tracing–guided LASIK with a 10% cylinder reduction protocol demonstrated excellent efficacy, safety, and predictability. This systematic adjustment achieved a near-perfect correction index, suggesting that clinical optimization of the automated algorithm is a valuable strategy for refining astigmatic outcomes in individualized laser surgery.