Symmetric offset versus asymmetric offset ablation with transepithelial refractive keratectomy

Area of Science:

• Ophthalmology
• Refractive Surgery
• Corneal Surgery

Background:

• Transepithelial photorefractive keratectomy (TransPRK) is a surface ablation technique for hyperopia, astigmatism, and mixed astigmatism.
• Current TransPRK treatments are centered on the corneal vertex, with pupil-center offsets.
• This study compares visual outcomes of symmetrical versus asymmetrical TransPRK profiles.

Purpose of the Study:

• To compare the visual results of symmetrical versus asymmetrical TransPRK treatment profiles.
• To evaluate the efficacy of TransPRK in correcting hyperopic and mixed astigmatism with different centering methods.

Main Methods:

• Retrospective analysis of 47 eyes with symmetrical offset and 51 eyes with asymmetrical offset TransPRK treatments.
• Intergroup comparisons using unpaired Student's T-tests.
• Preoperative to postoperative changes assessed using paired Student's T-tests.

Main Results:

• Both symmetrical and asymmetrical TransPRK groups achieved good refractive outcomes.
• 83% (symmetric) and 88% (asymmetric) of eyes were within 0.5 D of target spherical equivalent.
• 85% (symmetric) and 84% (asymmetric) of eyes achieved postoperative astigmatism of 0.5 D or lower.

Conclusions:

• No significant difference in refractive outcomes was found between symmetrical and asymmetrical TransPRK groups.
• TransPRK is effective for hyperopic and mixed astigmatism regardless of symmetrical or asymmetrical centering.
• Both treatment profiles provide comparable visual results for surface ablation refractive surgery.