Single-step transepithelial versus alcohol-assisted photorefractive keratectomy in the treatment of high myopia: a comparative evaluation over 12 months.

To evaluate refractive outcomes of single-step transepithelial photorefractive keratectomy (TransPRK) versus alcohol-assisted PRK (EtOH-PRK) for the correction of high myopia. This was a retrospective non-randomised comparative study conducted at the American University of Beirut Medical Center, Beirut, Lebanon. Eyes with myopia (spherical equivalent (SE) larger than -6.00 D) that had undergone EtOH-PRK treatment combined with mitomycin C and TransPRK (SE: -7.53±0.90 D and -7.24±0.77 D, p=0.062), using the Schwind Amaris excimer laser, were included. 59 eyes (37 patients) that had single-step TransPRK were compared with 59 eyes (36 patients) that had EtOH-PRK. Visual and refractive outcomes, including analysis of astigmatism, and corneal higher order aberrations (HOAs) at 6.0 mm optical zone, were compared for 12 months postoperatively. Baseline characteristics were similar between the two groups (p>0.05). The SE deviation from target (SEDT) at 1 week, 1, 3, 6 and 12 months follow-up visits were similar between groups (p=0.428). At 12 months, 81.3% and 73.3% of eyes that had undergone TransPRK and EtOH-PRK, respectively, were between ±0.50 D SEDT (p=0.381). Mean cylinder power was 0.33±0.26 D versus 0.41±0.30 D at 12 months follow-up (p=0.140). The mean success index was 0.50±0.50 for the TransPRK group and 0.49±0.52 for the EtOH-PRK group (p=0.939), while the absolute mean angle of error was 7.81°±61.98° vs 13.12°±71.86° (p=0.667), respectively. The change in total, spherical and comatic corneal HOAs were similar in both groups at 12 months (p>0.05). Haze was similar between both groups; two eyes had +1 haze at 12 months in the TransPRK group versus zero eyes among the EtOH-PRK group (p=0.154). Single-step TransPRK for high myopia with or without astigmatism appears to yield similar visual, refractive and safety results as EtOH-PRK.

Antonios R ，Abdul Fattah M ，Arba Mosquera S ，Abiad BH ，Sleiman K ，Awwad ST ... -  《-》

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.

Fattah MA ，Antonios R ，Arba Mosquera S ，Abiad B ，Awwad ST ... -  《-》

Consecutive myopia correction with transepithelial versus alcohol-assisted photorefractive keratectomy in contralateral eyes: one-year results.

To compare the postoperative efficacy, safety, and higher-order-aberrations (HOAs) between transepithelial photorefractive keratectomy (PRK) and alcohol-assisted PRK in contralateral eyes. Private clinic, Utrecht, The Netherlands. Comparative case series. Consecutive patients were randomized to have transepithelial PRK in 1 eye and alcohol-assisted PRK in the contralateral eye. In both eyes, aspheric treatments were planned with Custom Ablation Manager software and ablations performed with the Schwind Amaris system. Clinical outcomes were predictability, refraction, visual acuity, wavefront aberrations, and contrast and glare sensitivity. Paired t tests were applied for statistics. The study evaluated 66 eyes (33 patients). All patients completed the 1-year follow-up. At 1-year, 97% of eyes in both groups achieved an uncorrected distance visual acuity (UDVA) of 0.1 logMAR or better. No eye lost 2 or more lines of corrected distance visual acuity (CDVA); 97% of transepithelial PRK eyes and 91% of alcohol-assisted PRK eyes were within ±0.50 diopter (D) of the targeted refraction. The postoperative mean spherical equivalent was +0.07 D ± 0.23 (SD) and +0.01 ± 0.27 D, respectively. The CDVA, UDVA, and safety outcomes between transepithelial PRK and alcohol-assisted PRK were comparable. Profiles for both techniques applied to regular corneas preserved the eye's natural HOAs. Transepithelial PRK is faster to perform and it is an all-laser procedure, which might be less stressful for the patient. Mr. Ewering and Mr. Arba-Mosquera are employees of Schwind eye-tech-solutions. Dr. Luger has no financial or proprietary interest in any material or method mentioned.

Luger MH ，Ewering T ，Arba-Mosquera S 《-》

Past and present of corneal refractive surgery: a retrospective study of long-term results after photorefractive keratectomy and a prospective study of refractive lenticule extraction.

Surgical correction of refractive errors is becoming increasingly popular. In the 1990s, the excimer laser revolutionized the field of corneal refractive surgery with PRK and LASIK, and lately refractive lenticule extraction (ReLEx) of intracorneal tissue, using only a femtosecond laser, has become possible. Two new procedures were developed, ReLEx flex (FLEX) and ReLEx smile (SMILE). Until this thesis, only a few long-term studies of PRK with a relatively limited number of patients had been published; therefore, this thesis intended to retrospectively evaluate long-term outcomes after PRK for all degrees of myopia for a large number of patients. Furthermore, a prospective contralateral eye study comparing FLEX and SMILE, when treating high to moderate degrees of myopia, had not been performed prior to this study. This was the second aim of this thesis. In the first study, results from 160 PRK patients (289 eyes) were presented. Preoperative spherical equivalent ranged from -1.25 to -20.25 D, with 78% having low myopia (<-6 D). Average follow-up time was 16 years (range 13-19 years), making this the longest published follow-up study on PRK patients. Outcomes from eyes with low myopia were generally superior to outcomes from eyes with high myopia, at final follow-up. Seventy-two percent were within ± 1.00 D of target refraction, as compared to 47% of eyes with high myopia. However, results from a subgroup of unilateral treated PRK patients indicated that refraction at final follow-up was affected by myopic progression. Fifty percent of eyes with low myopia had uncorrected 20/20 distance visual acuity or better, as compared to 22% of eyes with high myopia. Haze did not occur if attempted corrections were <-4 D, and only eyes with high myopia lost two lines or more of CDVA (corrected distance visual acuity). Eighty-one per cent were satisfied or very satisfied with their surgery. The results support the continued use of the excimer laser for corneal surface ablation as a treatment option for correction of low degrees of myopia, and as the treatment of choice for subgroups of refractive patients (thin corneas, etc.). The results also highlight that treatment of higher degrees of myopia with standard PRK should only be done today under special circumstances, due to low refractive predictability, and high risk of corneal haze. Technological advances since then should be taken into account when comparing these results with contemporary techniques. In the second study, 35 patients were randomized to receive FLEX in one eye and SMILE in the other. Preoperative spherical equivalent refraction ranged from -6 to -10 D with low degrees of astigmatism. A total of 34 patients completed the 6 month follow-up period. Refractive and visual outcomes were very similar for the two methods, as well as tear film measurements and changes in corneal biomechanics. Ninety-seven percent were within ± 1.00 D of target refraction, no eyes lost two lines or more of CDVA, and contrast sensitivity was unaffected after both procedures. The changes in higher-order aberrations were also very similar. There were also no differences in tear film parameters 6 months after surgery, although less postoperative foreign body sensation was reported within the first week after surgery in SMILE eyes. Corneal sublayer pachymetry measurements demonstrated equally increased epithelial thickness 6 months after surgery. Contrary to expectations, it was not possible to measure the theoretical biomechanical advantages of a small corneal incision in SMILE as compared to a corneal flap in FLEX. The main differences between FLEX and SMILE were found when the corneal nerves and intraoperative complications were evaluated. Thus, corneal sensitivity was better preserved and corneal nerve morphology was less affected after SMILE, but intraoperative complications occurred more frequently, although without visual sequela. Finally, 97% were satisfied or very satisfied with both their surgeries. The results support the continued use of both FLEX and SMILE for treatment of up to high degrees of myopia. Overall, refractive and visual results for both procedures were good and similar, but from a biological point of view, the less invasive SMILE technique is more attractive, as demonstrated in this study, despite being slightly more surgically demanding than FLEX.

Vestergaard AH 《-》

Comparison of visual and refractive results after transepithelial and mechanical photorefractive keratectomy in myopia.

Yildirim Y ，Olcucu O ，Alagoz N ，Agca A ，Karakucuk Y ，Demirok A ... -  《-》