Epithelial Erosions and Refractive Results After Single-Step Transepithelial Photorefractive Keratectomy and Alcohol-Assisted Photorefractive Keratectomy in Myopic Eyes: A Comparative Evaluation Over 12 Months.

PURPOSE: To evaluate the epithelial erosion incidence and refractive results in myopic eyes undergoing single-step transepithelial photorefractive keratectomy (TransPRK) compared with alcohol-assisted photorefractive keratectomy (PRK). METHODS: This was a retrospective nonrandomized comparative study conducted at the American University of Beirut Medical Center. A total of 189 eyes that had undergone single-step transepithelial PRK (TransPRK) were compared with 189 matched eyes that had undergone alcohol-assisted PRK over a follow-up of 1 year. The incidence and symptoms of epithelial erosion were evaluated in both treatment groups using a post hoc questionnaire administered to patients selected in the study. Visual and refractive outcomes, including vector analysis of astigmatism, and corneal higher-order aberrations were also compared at 1-year postoperatively. RESULTS: Baseline characteristics were similar between 2 groups (P > 0.05). A slight difference was detected at 12-month follow-up in the refractive cylinder (P = 0.02) and difference vector (P = 0.01) between eyes that had undergone TransPRK versus alcohol-assisted PRK. All other visual and refractive outcomes were similar at 12-month follow-up between both groups. Of note, 9.9% of patients with alcohol-assisted PRK (10/101) reported to the clinic because of tearing and stabbing sensation within 1 week after contact lens removal as opposed to 1% (1/100) of the TransPRK group (P = 0.0097). Subclinical recurrent epithelial erosion symptoms occurred more frequently in alcohol-assisted PRK: soreness to touch, sharp pains, and eyelid sticking occurred in 26.0% versus 6.6%, 32.5% versus 7.9%, and 26.0% versus 6.6% among the patients who were treated with alcohol-assisted PRK versus those who were treated with TransPRK, respectively (P ≤ 0.002). CONCLUSIONS: Single-step TransPRK for myopic eyes yields refractive results similar to those of alcohol-assisted PRK but shows a lesser incidence of early postoperative epithelial erosions and subsequent subclinical recurrent erosions.

Laser in situ keratomileusis for high hyperopia with corneal vertex centration and asymmetric offset.

PURPOSE: To investigate refractive outcomes and induction of corneal higher order aberrations (HOA) in eyes that underwent laser-assisted in situ keratomileusis (LASIK) for high hyperopia correction using an aberration neutral profile with corneal vertex centration and asymmetric offset. METHODS: A total of 24 consecutive patients (38 eyes) who underwent LASIK by one surgeon using AMARIS 750S excimer laser and a Carriazo-Pendular microkeratome for flap creation were retrospectively analyzed. Eyes targeted for plano and with correction in the maximum hyperopic meridian strictly higher than +4D were included in the retrospective analysis. Patients were reviewed at 1, 3, and 6 months postoperatively. Postoperative monocular corrected distance visual acuity (CDVA) and uncorrected distance visual acuity (UDVA), manifest refraction, and corneal wavefront aberrations were compared with respective preoperative metrics. RESULTS: Mean preoperative spherical equivalent and refractive astigmatism was +4.07 ± 0.90 D and 1.37 ± 1.26 D, respectively, reducing to +0.28 ± 0.58D (p<0.0001) and 0.49 ± 0.47 D (p = 0.0001) at the last postoperative visit. Six months postoperatively, 78% of eyes achieved a UDVA of 20/25 or better. No eye lost more than 2 Snellen lines of CDVA at any follow-up. There was a statistically significant induction of vertical trefoil (+0.104 ± 0.299 µm, p<0.05), vertical coma (-0.181 ± 0.463 µm, p<0.01), horizontal coma (+0.198 ± 0.663 µm, p<0.05), spherical aberration (-0.324 ± 0.281 µm, p<0.0001), secondary vertical trefoil (+0.018 ± 0.044 µm, p<0.01), and secondary horizontal coma (+0.026 ± 0.083 µm, p<0.05). CONCLUSIONS: Laser-assisted in situ keratomileusis for high hyperopia using corneal vertex centration with asymmetric offset results in significant improvement in refraction and visual acuity although affected by significant induction of some higher order aberrations.