Transepithelial photorefractive keratectomy for myopia: effect of age and keratometric values (original) (raw)
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Journal of Cataract and Refractive Surgery, 2016
Background: To evaluate the safety, efficacy, and the refractive outcomes of single-step transepithelial photorefractive keratectomy (TransPRK) for the correction of mild, moderate, and high myopia. Methods: This study consecutively recruited 32 high myopic eyes, 32 mild myopic and 32 moderate myopic eyes. Eyes with myopia that had undergone TransPRK treatment. Pre-and post-operative visual and refractive data, corneal Higher Order Aberration (HOA) as well as safety and efficacy indices were analyzed at 6 months postoperatively. Results: Six months after TransPRK, the manifest refraction spherical equivalent (SE) was not significantly between high myopia group and moderate myopia group (p = 0.636). No eyes lost ≥2 lines of corrected distant visual acuity (CDVA) in high myopic eyes. The uncorrected distance visual acuity (UDVA) was significantly higher in low and moderate myopia groups than the high myopia group (P < 0.001; P = 0.002). The CDVA was not significantly different between moderate and high myopia groups (P = 0.057). There was no significant difference in mean safety index between high myopia group (1.01 ± 0.14) and mild myopia group (1.08 ± 0.15) (P > 0.05). The mean safety index was significantly higher in the moderate myopia group (1.16 ± 0.23) than in the high myopia group (1.01 ± 0.14) (P = 0.002). The efficacy index was significantly higher in the moderate myopia group (1.05 ± 0.20) than in the high myopia group (0.89 ± 0.17) (P = 0.02), and there was no significant difference between the high myopia group (0.89 ± 0.17) and the low myopia group (0.96 ± 0.16) (P = 0.14). Conclusions: The mean safety index was over 1.0 in the three groups. TransPRK showed acceptable safety and efficacy in the moderate myopic eyes, as well as mild and high myopic eyes. High myopic eyes got very similar refractive results with moderate myopic eyes six months postoperatively. The safety and efficacy indexes were not significantly different between the high myopia group and the low myopia group.
Journal of Ophthalmic & Vision Research, 2016
Purpose: To compare the effectiveness, safety and stability of the results of transepithelial photorefractive keratectomy (tPRK) with conventional photorefractive keratectomy (PRK) for low to moderate myopia. Methods: In this prospective non-randomized case-control study, patients with low to moderate myopia were assigned to the tPRK group (cases) or the PRK group (controls). In the tPRK group, eyes were treated using the Amaris excimer laser (SCHWIND eye-tech-solutions GmbH and Co. KG, Germany). Outcome measures included postoperative pain using McGill Pain Questionnaire, epithelial healing time, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, and safety and efficacy indexes which were compared between the study groups. Results: Three hundred forty eyes of 170 patients were enrolled in this study. Each study group comprised of 170 eyes of 85 patients. There was a significant difference between the two groups regarding the postoperative pa...
BMC ophthalmology, 2018
To evaluate the refractive and visual outcomes of Transepithelial photorefractive keratectomy (TransPRK) in the treatment of low to moderate myopic astigmatism. This retrospective study enrolled a total of 47 eyes that had undergone Transepithelial photorefractive keratectomy. Preoperative cylinder diopters ranged from - 0.75D to - 2.25D (mean - 1.11 ± 0.40D), and the sphere was between - 1.50D to - 5.75D. Visual outcomes and vector analysis of astigmatism that included error ratio (ER), correction ratio (CR), error of magnitude (EM) and error of angle (EA) were evaluated. At 6 months after TransPRK, all eyes had an uncorrected distance visual acuity of 20/20 or better, no eyes lost ≥2 lines of corrected distant visual acuity (CDVA), and 93.6% had residual refractive cylinder within ±0.50D of intended correction. On vector analysis, the mean correction ratio for refractive cylinder was 1.03 ± 0.30. The mean error magnitude was - 0.04 ± 0.36. The mean error of angle was 0.44° ± 7.42°...
BMC Ophthalmology, 2022
Background To assess transepithelial photorefractive keratectomy (tPRK) in terms of corneal epithelial healing rate, postoperative pain, postoperative discomfort, and visual and refraction outcomes compared to mechanical epithelial debridement PRK (mPRK) and alcohol-assisted PRK (aaPRK). Methods In this double-masked, randomized clinical trial, thirty-nine patients underwent tPRK in one eye and mPRK in the fellow eye (arm A), and 33 patients underwent tPRK in one eye and aaPRK in the contralateral eye (arm B). All surgical procedures were done using the Schwind Amaris excimer laser. The area of corneal epithelial defect in all eyes was captured and analyzed using ImageJ software. Results Mean epithelial healing time was respectively 3.74 ± 0.82 and 3.59 ± 0.79 days in tPRK versus mPRK ( P = 0.21) in arm A, and 3.67 ± 0.92 and 3.67 ± 0.74 days in tPRK versus aaPRK ( P = 1.00) in arm B. Accounting for the initial corneal epithelial defect area, the epithelial healing rate was faster...
Cornea, 2009
Purpose: To evaluate 8-year results of photorefractive keratectomy (PRK) for myopia in terms of safety, efficacy, stability, and late complications. Methods: From 371 myopic eyes of 203 patients who underwent PRK using NIDEK EC-5000 excimer laser with 5.5-to 6-mm ablation zones in Basir Eye Center, Tehran, Iran, during 1997-1998, data of 179 myopic eyes of 98 patients, who participated in annual examinations, were analyzed. Treated eyes were divided into 3 groups according to preoperative refraction: low myopia [#26.00 diopters (D)], moderate myopia (26.10 to 210.00 D), and high myopia (.210.00 D). The main outcome measures were safety, efficacy, stability, and postoperative complications. Results: Eight years after PRK, 69.64%, 44.44%, and 45.65% of the low, moderate, and high myopic groups were within 60.5 D of emmetropia. Sixteen eyes (4.31% of original cases) underwent retreatment mainly because of regression. Although a small myopic shift occurred up to 8 years after surgery, changes in myopic regression stabilized in all myopic groups within 24 months. Four eyes (2.06%) lost 2 lines of best spectacle-corrected visual acuity (1 eye for corneal haze and other 3 for problems not related to refractive surgery). Corneal haze occurred in 11.34% especially in medium and high myopic groups, but it cleared within 2 years in 68.2% of cases. Conclusions: Based on our study, PRK seems to be a safe, efficient, and stable surgical procedure, and if patients obtain a good result with the initial treatment, then their results are relatively stable over time.
Purpose: To assess the safety, efficacy and predictability of photorefractive keratectomy (PRK) [Tissuesaving (TS) versus Plano-scan (PS) ablation algorithms] of Technolas 217z excimer laser for correction of myopic astigmatism Methods: In this retrospective study one hundred and seventy eyes of 85 patients (107 eyes (62.9%) with PS and 63 eyes (37.1%) with TS algorithm) were included. TS algorithm was applied for those with central corneal thickness less than 500 µm or estimated residual stromal thickness less than 420 µm. Mitomycin C (MMC) was applied for 120 eyes (70.6%); in case of an ablation depth more than 60 μm and/or astigmatic correction more than one diopter (D). Mean sphere, cylinder, spherical equivalent (SE) refraction, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA) were measured preoperatively, and 4 weeks,12 weeks and 24 weeks postoperatively. Results: One, three and six months postoperatively, 60%, 92.9%, 97.5% of eyes had UCVA of 20 /20 or better, respectively. Mean preoperative and 1, 3, 6 months postoperative SE were-3.48±1.28 D (-1.00 to-8.75),-0.08±0.62D,-0.02±0.57 and-0.004± 0.29, respectively. And also, 87.6%, 94.1% and 100% were within ±1.0 D of emmetropia and 68.2, 75.3, 95% were within ±0.5 of emmetropia. The safety and efficacy indices were 0.99 and 0.99 at 12 weeks and 1.009 and 0.99 at 24 weeks, respectively. There was no clinically or statistically significant difference between the outcomes of PS or TS algorithms or between those with or without MMC in either group in terms of safety, efficacy, predictability or stability. Dividing the eyes with subjective SE≤4 D and SE≥4 D postoperatively, there was no significant difference between the predictability of the two groups. There was no intra-or postoperative complication. Conclusion: Outcomes of PRK for correction of myopic astigmatism showed great promise with both PS and TS algorithms.
Clinical Ophthalmology (Auckland, N.Z.), 2021
Purpose To evaluate the 12-months outcomes of photorefractive keratectomy (PRK) in patients with high myopia (≥ 6.0 diopters, D) compared with low-to-moderate myopia (< 6.0 D). Patients and Methods Records of 46 patients (69 eyes) who underwent PRK for myopic and astigmatic correction between October 2015 and December 2018 were reviewed. High myopic eyes (29 eyes) were compared with low-to-moderate myopic eyes (40 eyes). All surgeries were adjunct with 0.02% mitomycin C intraoperatively. Measured outcomes included postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent, corneal haze rate, and any complications. Results At 12 months post-PRK, 26 eyes (89.7%) in the high myopia and 39 eyes (97.5%) in the low-to-moderate myopia group had UDVA ≥ 20/20, (p=0.30). Average postoperative logMAR UDVA at 12 months was −0.04 (20/18) and −0.11 (20/15) for the high myopia and low-to-moderate myopia groups, resp...
Journal of Ophthalmology
Objective. To analyze the safety and efficacy of high-myopic PRK as an alternative to LASIK surgery in patients with a high preoperative percentage tissue altered (PTA). Design. Retrospective interventional case series. Participants. Charts of 256 consecutive eyes that underwent PRK with application of mitomycin-C 0.02% for high myopia were retrospectively reviewed. Methods. Refractive (refraction and refractive accuracy) and visual outcomes (uncorrected and corrected visual acuities), as well as occurrence of haze in the eyes with preoperative PTA expected to be higher than 40% with a 110-micron flap if undergoing LASIK surgery, were analyzed. Results. Mean follow-up was 7.3 ± 4.8 months. A total of 187 of 256 eyes (73.0%) were included in the analysis because they were expected to have a PTA greater than 40%, should they have undergone LASIK surgery. The actual mean PTA of those eyes following PRK was 31.8 ± 2.2%, and none had a PTA ≥ 40%. UDVA of 20/16, 20/20, and 20/25 or better...
Response of the cornea for up to four years after photorefractive keratectomy for myopia
Journal of Refractive …, 2006
PURPOSE: To analyze the long-term corneal topographic changes 4 years after myopic photorefractive keratectomy (PRK). METHODS: This study comprised 15 patients (30 eyes) who had PRK surgery with a scanning-spot excimer laser (Chiron Technolas 217C; Bausch & Lomb, Dornach, Germany) and were followed up to 4 years after surgery. The eyes were subdivided into three groups according to the preoperative spherical equivalent refraction. Corneal topographic maps were obtained for all eyes with a Placido disc topographer. Preoperative and follow-up topographical data were imported into a custom software program, which computed the average composite corneal maps and difference maps for each study group to quantify the anterior corneal changes following laser ablation. The software delineated three concentric zones of the corneal surface to characterize the regional corneal remodeling following the surgery. RESULTS: A signifi cant central corneal steepening (approximately 0.25 D, PϽ.001) was calculated between the 1-and 4-year postoperative maps in all study groups. A signifi cant steepening (PϽ.001) of the corneal periphery was also noted for the lower myopic ablations whereas a peripheral fl attening (PϽ.001) was observed for the deeper ablations between 1 and 4 years after surgery. CONCLUSIONS: The anterior corneal surface was observed to remodel for up to 4 years after surface ablation, steepening a mean of approximately 0.25 D.