Evaluation of Transepithelial Photorefractive Keratectomy TE PRK after

Evaluation of Trans-epithelial Photorefractive Keratectomy (TE PRK) after Modification of Laser Beam Profile David T. C. Lin MD FRCSC; Simon P. Holland MB, FRCSC, FRCS, MRCP; Umi K. Noh MB BCh BAO, Ms(Ophth) Purpose: Rapid visual recovery after PRK is important for patient acceptance of PRK. Aim: To determine if rate of recovery of uncorrected vision (UCVA) after TE PRK with existing Schwind Amaris (SA) laser beam profile (SPOA) could be improved with modification (SPNA) Methods: Retrospective comparative case series. Platform: Schwind Amaris (SA) and Wavelight Allegretto (WA) excimer lasers. • 42 eyes underwent TE PRK with SPOA • 443 eyes with SPNA. Range of spherical equivalent of manifest refraction ranged -1. 00 to -6. 00. Pre and post-operative assessment were analyzed at 2 week, 1 month and 3 months: • Uncorrected visual acuity (UCVA) • Best spectacle corrected visual acuity (BSCVA) • Manifest refraction (MR) • Predictability Results: Earlier visual recovery with improved beam profile (SPNA): At 2 week, achieving UCVA≥ 20/25: • 57% SPNA • 44% SPOA Ø with >10% difference between SPNA and SPOA At 1 month, achieving UCVA≥ 20/25: • 70% SPNA • 53% SPOA Ø with >10% difference still UCVA: SPNA vs. SPOA • UCVA ≥ 20/25 @ 2 weeks, 1 month, 3 month – SPOA: 44% (n=18) 53% (n=30) 83% (n=23) – SPNA: 57% (n=133) 70% (n=398) 89% (n=246) Results @ 3 month: UCVA: SPNA vs. SPOA vs. WA • UCVA ≥ 20/25 @ 3 month: – SPOA: 83% (n=23) – SPNA: 89% (n=243) – WA: 91% (n=319) At 3 month, achieving UCVA≥ 20/25: • 83% of SPOA • 89% of SPNA Ø difference narrowed to < 10% Conclusion: Advantages of SA 1050 include excellent tracking, high speed and user friendly treatment planning. Early TE PRK visual results trended to being better with Wavelight Allegretto than the Schwind Amaris using previous beam profile. After market beam smoothing profile change (July 2014) showed similar speed of visual recovery as seen with Wavelight Allegretto TE PRK simon_holland@telus. net Pacific Laser Eye Centre tel: (604)736 -2625