Visual performance after photorefractive keratectomy with a 6-mm ablation zone.

Area of Science:

• Ophthalmology
• Refractive Surgery
• Corneal Surgery

Background:

• Photorefractive keratectomy (PRK) is a common refractive surgery procedure.
• Assessing visual performance post-PRK is crucial for patient outcomes.
• The impact of a 6-mm ablation zone on visual quality requires detailed investigation.

Purpose of the Study:

• To prospectively evaluate the effect of photorefractive keratectomy (PRK) using a 6-mm ablation zone on best-spectacle-corrected visual performance.
• To compare high-contrast and low-contrast visual acuity before and after PRK.
• To identify factors influencing visual changes after PRK.

Main Methods:

• Prospective study of 164 eyes undergoing PRK with a 6-mm ablation zone.
• Measurement of best-spectacle-corrected high-contrast and low-contrast visual acuity (18% Weber contrast) with natural and dilated pupils.
• Preoperative and 3, 6, and 12-month postoperative assessments, including concurrent astigmatic keratotomy in 55 eyes.

Main Results:

• No significant change in high-contrast visual acuity with natural pupils 12 months post-PRK.
• Significant reduction in low-contrast visual acuity with natural pupils (mean change 0.04 logMAR).
• Greater reduction in low-contrast visual acuity with dilated pupils (mean change 0.13 logMAR), associated with corneal haze and astigmatic keratotomy.

Conclusions:

• PRK with a 6-mm zone can lead to reductions in visual performance, especially for low-contrast conditions.
• Dilated pupils exacerbate the loss in low-contrast visual acuity.
• Corneal haze and concurrent astigmatic keratotomy are linked to greater low-contrast visual acuity deficits.
• Best-spectacle-corrected low-contrast visual acuity is a sensitive indicator for assessing visual outcomes after refractive surgery.