# Exploring the Impact of Refractive and Ocular Residual Astigmatism on Stereopsis After Photorefractive Keratectomy in Patients With Myopic Astigmatism

## TL;DR

This study examines how refractive and residual astigmatism affect 3D vision after a type of laser eye surgery for nearsightedness.

## Contribution

The study identifies a potential link between higher astigmatism and improved stereopsis after PRK, and finds no significant impact of ORA on stereopsis outcomes.

## Key findings

- Higher cylindrical error was associated with stereopsis improvement after PRK (p = 0.04).
- No significant impact of ORA on stereopsis outcomes was found (p = 0.77).
- Stereopsis slightly improved on average after PRK, but the change was not statistically significant (p = 0.17).

## Abstract

To investigate the impact of refractive and ocular residual astigmatism (ORA) on stereopsis after photorefractive keratectomy (PRK) for the correction of myopic astigmatism.

This prospective observational study was conducted on patients who underwent PRK for the treatment of myopia and myopic astigmatism using a Schwind Amaris 1050RS excimer laser system. Stereoacuity was measured using the Stereo Fly Test before and after the surgery. We evaluated the impact of pre‐op refractive and internal astigmatic components on stereopsis outcome after surgery. To calculate ORA, we calculated the vectorial difference between corneal plane refractive astigmatism and keratometric astigmatism.

Ninety‐six eyes from 96 patients including 70 females (72.9%) with a mean age of 29.83 ± 7.39 years were enrolled. The average stereoacuity measured in log units before and after PRK was 1.65 ± 0.09 and 1.63 ± 0.07, respectively (p = 0.17). Patients who showed stereopsis improvement had a higher mean cylindrical error compared to those who did not (p = 0.04). The average pretreatment ORA was 0.84 ± 0.37 in patients who experienced deterioration in stereopsis, 0.77 ± 0.35 in patients who maintained the same level, and 0.80 ± 0.35 in patients who showed improvement (p = 0.77).

This study showed the potential relationship between higher astigmatism and the enhancement of stereopsis after PRK. Furthermore, our study found no significant impact of ORA on the outcomes of stereopsis following PRK.