Outcomes Of Transepithelial Photorefractive Keratectomy Research Articles

Early visual and clinical outcomes of transepithelial photorefractive keratectomy versus transepithelial keratectomy with smart pulse technology for myopia

Abstract: PURPOSE: The purpose of this study was to compare early visual outcomes, epithelial healing, and stromal haze between transepithelial photorefractive keratectomy (Trans-PRK) using smart pulse technology (SPT) with traditional Trans-PRK. METHODOLOGY: This study is a retrospective, comparative study conducted at a private eye center in “Riyadh, Saudi Arabia,” investigating myopic patients who underwent either Trans-PRK with SPT (study group) or traditional Trans-PRK (control group). The patients were assessed preoperatively and followed up at 1 week and 2 months postoperatively. The main outcomes included uncorrected distance visual acuity (UDVA), corneal haze, and corneal epithelial defect. RESULTS: This study included 501 eyes, of them, 222 eyes (44.3%) underwent Trans-PRK with SPT. The UDVA in the study group was significantly better 1 week postoperatively (P < 0.05). For the 2-month follow-up visits, there was no significant difference between the groups. Epithelium healing and stromal haze were comparable in the two groups without significant differences between them. CONCLUSION: Transepithelial photorefractive keratectomy with SPT yielded better short-term visual outcomes than traditional Transepithelial photorefractive keratectomy.

Clinical Outcomes of Transepithelial Photorefractive Keratectomy Performed with Smart Pulse Technology for the Correction of Moderate to High Myopia.

Purpose: To evaluate the safety and efficacy of the transepithelial photorefractive keratectomy (TransPRK) performed using smart pulse technology (SPT) in myopic eyes with refractive error ranging from -5.25 D to -9.75 D. Methods: This retrospective study evaluated the outcomes of SPT-assisted TransPRK in 150 eyes performed using a 1050 Hz AMARIS excimer laser. Results: At 6 months postoperative, 98% of eyes achieved uncorrected distance visual acuity (UDVA) of 20/25 or better, and postoperative UDVA within one line of preoperative corrected distance visual acuity (CDVA). No eyes lost any line of CDVA. Residual spherical equivalent refraction and cylinder within ±0.50 D of intended correction were achieved in 72% and 67% of eyes, respectively. Ninety-seven percent of eyes reported no halos and glare. Conclusions: TransPRK using a 1050 Hz excimer laser with SPT showed excellent predictability, safety, and efficacy for moderate to high myopia correction.

Evaluation of the efficiency and safety of TransPRK and FS-LASIK refractive procedures on patients with astigmatism and amblyopia.

Purpose: To compare the outcomes of transepithelial photorefractive keratectomy (transPRK) with femtosecond laser assisted in situ keratomileusis (FS-LASIK) for the correction of astigmatism on amblyopic eyes. Methods: The design was a retrospective interventional study on 37 eyes with hyperopic or mixed astigmatism and refractive amblyopia, which underwent transPRK or FS-LASIK. The patients were distributed into 2 groups according to the technique used. Data was collected from patient files and comparison between groups was performed. The main outcomes measured were corrected distance visual acuity (CDVA), sphere, cylinder, spherical equivalent (SEQ), efficiency and safety indexes. Results: In the transPRK group, SEQ improved significantly after 1 month, from 2.08 ± 2.02D (p<0.01) to 0.125 ± 0.86D and at the 12 month visit to -0.04 ± 0.62D (p>0.05), sphere improved from 4.03 ± 1.44D preoperatively to 0.67 ± 0.9D at 1 month (p<0.05) and further to 0.44 ± 0.71 at 12 months (p<0.05). CDVA improved from 0.194 ± 0.11 logMAR to 0.115 ± 0.1 logMAR at the 1-year visit. Safety index after 1 month was 1.09 ± 0.2 and 1.12 ± 0.35 at the 1-year visit. Efficiency index was 0.95 ± 0.22 at 1 month and 1.03 ± 0.34 after 1 year. In FS-LASIK group, SEQ improved after 1 month, from 2.28 ± 3.04 to -0.79 ± 0.73D (p<0.01), and further to -0.49 ± 0.79 (p>0.05) at the 12 month visit, sphere improved from 4.11 ± 2.35D preoperatively to -0.42 ± 0.66D at 1 month (p<0.05) and further to -0.08 ± 0.75D at 12 months (p<0.05). CDVA also improved from 0.191 ± 0.1 logMAR to 0.140 ± 0.1 logMAR at 1 year. Safety index after 1 month was 1.1 ± 0.2 and 1.16 ± 0.21 at the 1-year visit. Efficiency index was 0.98 ± 0.27 at 1 month and 1.06 ± 0.23 after 1 year. Conclusion: Both procedures were safe and efficient in improving visual acuity for patients with mixed and hyperopic astigmatism and refractive amblyopia. Abbreviations: transPRK = transepithelial photorefractive keratectomy, FS-LASIK = femtosecond laser in situ keratomileusis, logMAR = logarithm of the Minimum Angle of Resolution, BCVA = best corrected distance visual acuity, CDVA = corrected distance visual acuity.

Transepithelial Photorefractive Keratectomy Compared to Conventional Photorefractive Keratectomy: A Meta-Analysis.

This meta-analysis review compares the primary and secondary outcomes of transepithelial photorefractive keratectomy (TPRK) to the conventional photorefractive keratectomy (PRK), in terms of efficacy, predictability, safety, and patient perspectives. A total of 1711 eyes with PRK (811 eyes) and TPRK (900 eyes) from 12 studies were included through bibliographic searches. The main outcomes were efficacy, predictability, and safety parameters, and the secondary outcomes included visual and patient-reported parameters. The effect measures were weighted mean differences with 95% confidence intervals (CI) which were derived from the random-effects model of the meta-analysis to account for possible heterogeneity. TPRK procedure presents a comparable status in the main outcome and a very dominant significance in all the secondary outcomes in this meta-analysis. This study updates the evidence of the accuracy of TPRK procedure for surgical correction of all refractive errors and was deemed safer with less surgical time required and an early healing time.

Clinical outcomes of transepithelial photorefractive keratectomy with epithelial ablation targeting actual epithelial thickness vs default laser platform values.

To investigate the clinical outcomes of transepithelial photorefractive keratectomy (tPRK) with actual epithelial thickness vs default software values. Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. Prospective controlled study. Patients with refractive spherical error of -1.50 to -7.00 diopters (D) and refractive astigmatism up to 4.00 D were consecutively enrolled and divided into 2 groups: group 1 undergone tPRK with actual central and peripheral epithelial thickness input in right eyes, group 2 undergone tPRK with actual central and 10 mm higher peripheral epithelial thickness in right eyes. Left eyes in both groups underwent tPRK with default protocol. Outcome measures were induced refractive error, achieved optical zone (OZ), and wasted stromal tissue. 83 patients were included in this study. Mean ± SD of induced spherical equivalent was +0.15 ± 0.39 D and +0.01 ± 0.35 D in right and left eyes of group 1 (P = .01) and +0.04 ± 0.22 D and +0.03 ± 0.23 D in right and left eyes of group 2 (P = .75), respectively. There was no statistically significant difference between wasted tissue between right and left eyes in group 1 and group 2 (P = .77 and P = .49, respectively). OZ contraction was significantly higher in right compared with left eyes in group 1 (P = .05), but not in group 2 (P = .95). In tPRK, refractive outcomes, wasted tissue, and OZ contraction depend little on preexisting corneal epithelial thickness in corneas with normal range epithelial thickness. However, OZ contraction may be a concern in lower amount of ablations.

Femtosecond laser assisted in situ keratomileusis (FS-LASIK) yields better results than transepithelial photorefractive keratectomy (Trans-PRK) for correction of low to moderate grade myopia

The purpose of this study was to compare the outcomes of transepithelial photorefractive keratectomy (Trans-PRK) with femtosecond laser assisted in situ keratomileusis (FS-LASIK) for the correction of low to moderate myopia. A retrospective cohort study design was used. The study group included patients with myopia less than -6.0 D, with or without concomitant astigmatism under 2.0 D, who were treated with FS-LASIK or Trans-PRK in 2013 through 2014. Background, clinical and outcome data were collected from the patient files. A comparison between eyes treated with FS-LASIK or Trans-PRK was performed. The Trans-PRK group was comprised of 1793 eyes and the FS-LASIK group of 666 eyes. Mean ± SD spherical equivalent (SE) refraction prior to surgery was -3.43 ± 1.27 D in the Trans-PRK group and -3.18 ± 1.34 D in the FS-LASIK group (p < 0.001). Efficacy index values were 0.95 ± 0.14 in the Trans-PRK group and 0.98 ± 0.12 in the FS-LASIK group (p < 0.001), and corresponding safety index values were 0.96 ± 0.13 and 0.99 ± 0.12 (p < 0.001). Distance from target refraction was 0.45 ± 0.42 D in Trans-PRK group and 0.43 ± 0.38 D in the FS-LASIK group (p = 0.537); 71.6% and 74.2% of eyes were within ±0.5 D of attempted correction, respectively (p = 0.193). Both Trans-PRK and FS-LASIK demonstrated excellent results, mostly comparable with the current literature. FS-LASIK achieved better results than Trans-PRK surgery in the efficacy and safety parameters.

Comparison of clinical results between trans-PRK and femtosecond LASIK for correction of high myopia

BackgroundTo compare the clinical outcomes of transepithelial photorefractive keratectomy (TPRK) with femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for correction of high myopia.MethodsIn this prospective, non-randomised, cohort study, 85 eyes of 46 patients treated with TPRK and 80 eyes of 42 patients treated with FS-LASIK were included. All eyes were highly myopic (spherical equivalent refraction <− 6.00 diopters). Both TPRK and FS-LASIK were performed by Schwind Amaris 750S excimer laser. Visual acuity, refraction, corneal high order aberration (HOA) and other variables were analyzed before and at 1, 3, 6, 12 months after surgery.ResultsAt 12 months after surgery, uncorrected logMAR distance visual acuity (UDVA) in the TPRK and FS-LASIK groups was − 0.04 ± 0.04 and − 0.01 ± 0.08, respectively (P = 0.039). Corrected logMAR distance visual acuity (CDVA) was − 0.06 ± 0.05 and − 0.04 ± 0.05 in both groups (P = 0.621). For UDVA, 86% of eyes in the TPRK group and 80% in the FS-LASIK group remained unchanged or improved one or more logMAR lines (P = 0.314), compared to preoperative CDVA. For CDVA, 97% of eyes in the TPRK group and 90% in the FS-LASIK group remained unchanged or improved one or more lines (P = 0.096), compared to preoperative CDVA. Spherical equivalent refraction was − 0.05 ± 0.39 and − 0.26 ± 0.47 in both groups (P = 0.030). 87% of eyes in the TPRK group and 73% in the FS-LASIK group achieved ±0.50 D target refraction (P = 0.019). All 85 eyes (100%) in the TPRK group and 75 eyes (92%) in the FS-LASIK group were within ±1.00 D of target (P = 0.003). Root mean square (RMS) of corneal total HOA and vertical coma in the TPRK group were lower compared with the FS-LASIK group (P < 0.001 for both variables).ConclusionsTPRK and FS-LASIK showed good safety, efficacy and predictability for correction of high myopia. Clinical outcomes of TPRK were slightly better than FS-LASIK.

Clinical outcomes of transepithelial photorefractive keratectomy versus femtosecond laser assisted keratomileusis for correction of high myopia in South Egyptian population

To evaluate the safety and efficacy of transepithelial photorefractive keratectomy (t-PRK) with adjuvant mitomycin C (MMC) versus femtosecond laser assisted keratomileusis (Femto-LASIK) in correction of high myopia. Prospective randomized comparative study including 156 eyes of 156 patients with high myopia and a spherical equivalent refraction (SER) <-6.00 D. They were divided randomly into two groups: Group A included 72 eyes treated with t-PRK with adjuvant MMC and Group B included 84 eyes treated with Femto-LASIK. Visual acuity, SER, corneal topography, pachymetry and keratometry were assessed for 12mo postoperatively. The preoperative mean SER was -8.86±1.81 and -9.25±1.70 D in t-PRK MMC group and Femto-LASIK respectively (P=0.99) which improved to -0.65±0.43 D and -0.69±0.50 D at 12mo follow up. Mean SER remained stable during the 12mo of follow-up, with no statistically significant difference between the two groups (P=0.64). In t-PRK MMC group, only six eyes needed retreatment after six months of follow up. And two eyes showed haze (one reversible haze grade 2, while the other had dense irreversible haze grade 4). t-PRK MMC provides safe and satisfactory visual outcomes and acceptable risk as Femto-LASIK in patients with high myopia.

Transepithelial Photorefractive Keratectomy in Moderate to High Astigmatism With a Non-wavefront-Guided Aberration-Neutral Ablation Profile.

To evaluate the outcomes of transepithelial photorefractive keratectomy (PRK) in moderate to high astigmatism with a non-wavefront-guided aberration-neutral ablation profile using SmartPulse allocation. In this retrospective study, myopic patients with a preoperative cylinder of 2.00 diopters (D) or greater were analyzed at 3 months of follow-up. Transepithelial PRK treatments were performed in each patient with the Amaris 1050RS laser (SCHWIND eye-tech-solutions, Kleinostheim, Germany) creating aspheric ablation profiles by applying a SmartPulse allocation. Standard examinations and wavefront analyses were included for low and high ocular residual astigmatism subgroups. Fifty-eight eyes (44 patients) were included in the cohort. The eyes were divided into separate ocular residual astigmatism subgroups: 17 eyes presented with less than 0.50 D (low ocular residual astigmatism) and 24 eyes with greater than 0.75 D (high ocular residual astigmatism). The mean refractive cylinder in the entire cohort was 2.84 ± 0.86 D preoperatively and 0.40 ± 0.39 D postoperatively, with 81% of the eyes within 0.75 D of the target astigmatism. At 3 months of follow-up, significant improvement (P < .05) was seen in terms of sphere, cylinder, spherical equivalent, and uncorrected (UDVA) and corrected (CDVA) distance visual acuity. CDVA improved in 40% of eyes and 3% of eyes lost one line of CDVA. No clinically relevant changes were seen in higher order aberrations. The refractive changes showed an excellent match with the keratometric changes. The difference between the low and high ocular residual astigmatism subgroups was not significant except for the change of Snellen lines of CDVA (P < .05). Transepithelial PRK using a non-wavefront-guided aberration-neutral ablation profile performed by applying SmartPulse allocation yielded excellent visual outcomes. The preoperative astigmatism was reduced to subclinical values. Both subgroups were effective in terms of UDVA, CDVA, spherical and astigmatic correction, and preserving higher order aberrations. However, the low ocular residual astigmatism subgroup was slightly more prone to gain lines of CDVA. [J Refract Surg. 2018;34(7):466-474.].

Clinical outcomes of Transepithelial photorefractive keratectomy to treat low to moderate myopic astigmatism

BackgroundTo evaluate the refractive and visual outcomes of Transepithelial photorefractive keratectomy (TransPRK) in the treatment of low to moderate myopic astigmatism.MethodsThis 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.ResultsAt 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°and 80.9% of eyes had axis shift within ±10°. The absolute astigmatic error of magnitude was statistically significantly correlated with the intended cylinder correction (r = 0.48, P < 0.01).ConclusionsTransPRK showed safe, effective and predictable results in the correction of low to moderate astigmatism and myopia.

Z-LASIK and Trans-PRK for correction of high-grade myopia: safety, efficacy, predictability and clinical outcomes.

The aim of the study was to examine the outcomes of transepithelial photorefractive keratectomy (Trans-PRK) and Femtosecond Laser-assisted in situ keratomileusis (Z-LASIK) for the correction of high myopia. A retrospective cohort study design was used. The study group included 792 eyes with high-grade myopia (-6.0 diopters or higher) or high-grade myopia with astigmatism that were treated with Z-LASIK or Trans-PRK in 2013 through 2014 in an optical outpatient clinic of a large private medical service. The Trans-PRK group comprised of 674 eyes with a spherical equivalent (SE) of -7.87±1.46 and the Z-LASIK group comprised of 118 eyes with a SE of -7.19±0.81 (P<0.001). The mean postoperative SE in the Trans-PRK group was -0.06 and -0.02 in the Z-LASIK group (P=0.545). Efficacy index values were 0.92 in the Trans-PRK group and 0.95 in the Z-LASIK group (P=0.083), and corresponding safety index values were 0.95 and 0.97 (P=0.056). An UCVA of 20/40 or better was achieved in 94.20% of eyes in the Trans-PRK group, and 98.31% in the Z-LASIK group (P=0.063). The majority of eyes in both the Trans-PRK and Z-LASIK groups were within±0.5D of attempted correction: 59.35 and 64.71%, respectively (P=0.271). Both Trans-PRK and Z-LASIK demonstrated excellent efficacy, safety and predictability profiles, with results comparable and in some cases superior to the current literature. Results of Z-LASIK were slightly better than those of Trans-PRK, though the preoperative SE of the latter was higher.