Retrospective Analysis Comparing the Preoperative and Postoperative "Q" Values for 2 Different Lasers in Refractive...

Area of Science:

• Ophthalmology
• Corneal Surgery
• Refractive Surgery

Background:

• Corneal asphericity (Q value) influences visual quality.
• Maintaining the natural prolate shape of the cornea is desirable after refractive surgery.
• Photorefractive keratectomy (PRK) is a common procedure for myopia correction.

Purpose of the Study:

• To compare changes in corneal asphericity (Q value) after PRK for myopia correction.
• To evaluate differences between VISX Wavefront-guided and Allegretto Wave Wavefront-optimized treatments.
• To assess the impact of different PRK platforms on the cornea's natural shape.

Main Methods:

• Retrospective database analysis of 51 patient records (102 eyes).
• Data collected from the Joint Warfighter Refractive Surgery Center database.
• Calculation of the change in Q value per diopter of treatment sphere post-PRK.

Main Results:

• The average change in Q value per diopter was 0.12 (±0.04) for Allegretto and 0.14 (±0.04) for VISX (P = 0.004).
• Allegretto treatment showed a statistically significant smaller change in Q value compared to VISX.
• No significant differences were found in preoperative vs. postoperative best-corrected visual acuity (BCVA), low-contrast BCVA, or quality of vision complaints.

Conclusions:

• Allegretto Wavefront-optimized PRK for low to moderate myopia better preserves the cornea's native prolate shape compared to VISX Wavefront-guided PRK.
• Both PRK platforms yielded comparable postoperative visual outcomes.
• The findings suggest a potential advantage of Wavefront-optimized treatments in maintaining corneal geometry.