Femtosecond LASIK Induces Less Astigmatism Than PRK in Hyperopia Correction

Femtosecond laser-assisted in situ keratomileusis (LASIK) induces less postoperative astigmatism than photorefractive keratectomy (PRK) with Mitomycin-C (Biochem Pharmaceutical Industries Ltd) in patients with hyperopia, according to research published in the Journal of Cataract and Refractive Surgery.

Researchers conducted a retrospective study to compare the long-term visual and refractive outcomes of hyperopic excimer ablation using alcohol-assisted PRK with those of femtosecond LASIK for the correction of hyperopia. 

The main outcome measures were spherical equivalent deviation from target (SEDT), manifest refraction, and visual acuity. Patients had at least 3 years of follow up after surgery. 

The study included 83 eyes that underwent PRK and 83 matched eyes that underwent femtosecond LASIK. The groups showed no significant differences in any baseline characteristics. The preoperative manifest refraction spherical equivalent was 2.44±1.18 diopters (D) in the PRK group and 2.20±0.87 D in the femtosecond LASIK group (P =.133). The preoperative manifest cylinder was -0.77±0.89 D in the PRK group and -0.61±0.59 D in the femtosecond LASIK group (P =.175).

At postoperative 3 years, the researchers found the SEDT was 0.28±0.66 D in the PRK group and 0.40±0.56 D in the LASIK group (P =.222) and the manifest cylinder was -0.55±0.49 D in the PRK group and -0.30±0.34 D in the femtosecond LASIK group (P <.001). They reported a mean difference vector of 0.59±0.46 for the PRK group and 0.38±0.32 for the LASIK group (P <.001) and found 13.3% of eye in the PRK group and 0% of eyes in the LASIK group had more than 1 D of manifest cylinder (P =.003).

Both groups “achieved good visual and refractive results with satisfactory safety, efficacy and predictability. Femtosecond LASIK appears to be better in terms of the stability of the initial refractive outcome and spherical equivalent predictability, and clearly better in terms of the induced postoperative astigmatism,” wrote the authors.

The primary limitation of the study was the retrospective design.

Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.