Dataset Information

Transepithelial photorefractive keratectomy: a prospective randomized comparative study between the two-step and the single-step techniques.

ABSTRACT:

Objectives

To assess and compare the six-month outcome of the two-step transepithelial phototherapeutic keratectomy- photorefractive keratectomy (PTK-PRK) and the single-step transepithelial PRK for myopia and myopic astigmatism.

Methods

A prospective randomized study. The study enrolled 100 eyes of 50 patients with mild to moderate myopia or myopic astigmatism stratified into two groups, PTK-PRK (n = 50 eyes) and single step PRK (n = 50 eyes). Primary outcome measures were visual acuity and manifest refraction. Secondary outcome measures were epithelial healing duration, post-PRK pain scores and 3-month postoperative haze grading.

Results

Preoperative characteristics were similar in both groups (p value > 0.05). The mean uncorrected distance visual acuity (UDVA) at 1 week, 1 month, 3 and 6 months was significantly better in the single-step PRK group than in the two-step PTK-PRK group (p < 0.001). The mean manifest sphere, cylinder and spherical equivalent showed a significant difference at all follow up visits in favour of the single-step PRK (p value < 0.001). Epithelial healing duration was faster in single-step PRK (p value < 0.001). Pain scores were significantly lower following single-step PRK at 8 h, 1 day, 3 days (p value < 0.001) but were similar at the 7th day. Haze scores showed no statistical difference between the two groups at 3-month follow-up.

Conclusion

The two transepithelial PRK techniques were effective in correcting mild to moderate myopia and myopic astigmatism. However, Single-step transepithelial PRK achieved faster visual recovery, better refractive outcome and shorter epithelial healing time with less post-PRK pain.

Clinical trials registry

(Clinical Trials.gov Identifier): NCT04710082.

SUBMITTER: Abdel-Radi M

PROVIDER: S-EPMC10219954 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature

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Publications

Transepithelial photorefractive keratectomy: a prospective randomized comparative study between the two-step and the single-step techniques.

Abdel-Radi Mahmoud M Shehata Mohamed M Mostafa Magdi Mohammad MM Aly Mohamed Omar M MOM

Eye (London, England) 20220721 8

<h4>Objectives</h4>To assess and compare the six-month outcome of the two-step transepithelial phototherapeutic keratectomy- photorefractive keratectomy (PTK-PRK) and the single-step transepithelial PRK for myopia and myopic astigmatism.<h4>Methods</h4>A prospective randomized study. The study enrolled 100 eyes of 50 patients with mild to moderate myopia or myopic astigmatism stratified into two groups, PTK-PRK (n = 50 eyes) and single step PRK (n = 50 eyes). Primary outcome measures were visual ...[more]

PMID: 35864163

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Project description:BackgroundConventional mechanical or alcohol-assisted photorefractive keratectomy (PRK) techniques for correction of hyperopia and hyperopic astigmatism were associated with inconsistent results. The aim of this study is to evaluate the 12-month visual and refractive outcomes of the relatively new single-step transepithelial photorefractive keratectomy (TE-PRK) for moderate hyperopia and hyperopic astigmatism.MethodsThis is a prospective interventional study. Forty-eight eyes of 30 patients with moderate hyperopia or hyperopic astigmatism with a cycloplegic spherical equivalent refraction (SEQ) between 2.0 and 4.5 diopters (D) underwent single-step StreamLight® TE-PRK using EX500 excimer laser (Alcon Laboratories, USA). The main outcome measures were recorded at 6 and 12 months postoperatively including assessment of logarithm of the minimum angle resolution (logMAR) uncorrected and corrected distance visual acuity (UDVA, CDVA), cycloplegic refraction, corneal topographic changes as well as post-PRK peripheral haze grading.ResultsThe mean preoperative cycloplegic SEQ was significantly reduced from 3.21 ± 0.61 D to 0.35 ± 0.04 D and 0.41 ± 0.04 D at 6 and 12 months, respectively (P < 0.001). The mean preoperative UDVA significantly improved from 0.53 ± 0.02 logMAR to 0.07 ± 0.01 logMAR and 0.08 ± 0.01 logMAR at 6 and 12 months, respectively (P < 0.001) while the mean preoperative logMAR CDVA showed non-significant change over time throughout the study (P = 0.135). At the end of the study, 41 eyes (85.4%) achieved UDVA of 20/25 or better and no eye lost any lines of CDVA. Thirty-eight eyes (79.1%) had a postoperative cycloplegic cylinder of 0.5 D or less at 12 months. The mean preoperative mean keratometry showed significant increase at 6 and 12 months postoperatively (P < 0.001) while there was no significant change between the two postoperative visits denoting topographic stability (P = 0.058). The mean postoperative Q value at 6 and 12 months showed a significant prolate shift (P < 0.001). No haze was observed in 62.5% and 85.4% of the enrolled eyes at 6 and 12 months, respectively.ConclusionsSingle-step StreamLight® TE-PRK for moderate hyperopia and hyperopic astigmatism achieved acceptable visual and refractive outcomes.Trial registration(Clinicaltrials.gov): NCT05261685, 2 March 2022, retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT05261685.

Project description:BackgroundStudies suggest that transepithelial photorefractive keratectomy (TransPRK) with the all-surface laser ablation (ASLA)-SCHWIND platform is effective and safe for both low-moderate myopia and high myopia. In most studies, mitomycin-C is administered immediately after surgery to prevent corneal opacification (haze), which is a significant complication of photorefractive keratectomy in general. However, there is evidence that adjuvant mitomycin-C induces endothelial cytotoxicity. Moreover, a recent study showed that omitting adjuvant mitomycin-C did not increase haze in low-moderate myopia. The present case-series study examined the efficacy, safety, and haze rates of eyes with high myopia that underwent ASLA-SCHWIND TransPRK without adjuvant mitomycin-C.MethodsAll consecutive eyes with high myopia (≤-6 D) that were treated in 2018-2020 with the SCHWIND Amaris 500E® TransPRK excimer laser without adjuvant mitomycin-C in a tertiary-care hospital (France) and were followed up for 6 months were identified. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and spherical equivalent (SE) were recorded before and after surgery. Postoperative haze was graded using the 4-grade Fantes scale. Efficacy rate (frequency of eyes with 6-month UCVA ≤0.1 logMAR), safety rate (frequency of eyes that lost <2 BSCVA lines), predictability (frequency of eyes with 6-month SE equal to target SE±0.5 D), efficacy index (mean UCVA at 6 months/preoperative BSCVA), and safety index (BSCVA at 6 months/preoperative BSCVA) were computed.ResultsSixty-nine eyes (38 patients) were included. Mean preoperative and 6-month SE were -7.44 and -0.05 D, respectively. Mean 6-month UCVA and BSCVA were 0.00 and -0.02 logMAR, respectively. Efficacy rate and index were 95.7% and 1.08, respectively. Safety rate and index were 95.7% and 1.13, respectively. Predictability was 85.5%. Grade 3-4 haze never arose. At 6 months, the haze rate was zero.ConclusionsASLA-SCHWIND TransPRK without mitomycin-C appears to be safe as well as effective and accurate for high myopia.

Project description:Purpose: To evaluate the change in corneal biomechanics in patients with postoperative ectasia risk when combining two common laser vision correction procedures (tPRK and FS-LASIK) with cross-linking (in tPRK Xtra and FS-LASIK Xtra). Methods: The study included 143 eyes of 143 myopic, astigmatic patients that were divided into non-cross-linked refractive surgery groups (non-Xtra groups, tPRK and FS-LASIK) and cross-linked groups (Xtra groups, tPRK Xtra and FS-LASIK Xtra) according to an ectasia risk scoring system. The eyes were subjected to measurements including the stress-strain index (SSI), the stiffness parameter at first applanation (SP-A1), the integrated inverse radius (IIR), the deformation amplitude at apex (DA), and the ratio of deformation amplitude between apex and 2 mm from apex (DARatio2mm). The measurements were taken preoperatively and at 1, 3, and 6 months postoperatively (pos1m, pos3m, and pos6m). Posterior demarcation line depth from the endothelium (PDLD) and from the ablation surface (DLA) were recorded at pos1m. Results: SP-A1 significantly decreased, while IIR, deformation amplitude, and DARatio2mm increased significantly postoperatively in all four groups (p < 0.01)-all denoting stiffness decreases. In the FS-LASIK group, the changes in IIR, DA, and DARatio2mm were 32.7 ± 15.1%, 12.9 ± 7.1%, and 27.2 ± 12.0% respectively, which were significantly higher (p < 0.05) compared to 20.1 ± 12.8%, 6.4 ± 8.2%, and 19.7 ± 10.4% in the FS-LASIK Xtra group. In the tPRK group, the change in IIR was 27.3 ± 15.5%, significantly larger than 16.9 ± 13.4% in the tPRK Xtra group. The changes of SSI were minimal in the tPRK (-1.5 ± 21.7%, p = 1.000), tPRK Xtra (8.4 ± 17.9%, p = 0.053), and FS-LASIK Xtra (5.6 ± 12.7%, p = 0.634) groups, but was significant in the FS-LASIK group (-12.1 ± 7.9%, p < 0.01). After correcting for baseline biomechanical metrics, preoperative bIOP and the change in central corneal thickness (△CCT) from pre to pos6m, the changes in the IIR in both FS-LASIK and tPRK groups, as well as DA, DARatio2mm and SSI in the FS-LASIK group remained statistically greater than their corresponding Xtra groups (all p < 0.05). Most importantly, after correcting for these covariates, the changes in DARatio2mm in the FS-LASIK Xtra became statistically smaller than in the tPRK Xtra (p = 0.017). Conclusion: The statistical analysis results indicate that tPRK Xtra and FS-LASIK Xtra effectively reduced the biomechanical losses caused by refractive surgery (tPRK and FS-LASIK). The decrease in corneal overall stiffness was greater in FS-LASIK than in tPRK, and the biomechanical enhancement of CXL was also higher following LASIK than after tPRK.

Project description:PurposeKeratoconus (KC) leads to gradual progressive loss of vision in young and adult patients. For the purpose of visual rehabilitation and for hindering KC progression in patients, we designed this study. The main aim of this study is to help the KC patients to improve and stabilize their vision.MethodsThis prospective consecutive uncontrolled study includes 36 eyes of 36 patients with moderate degree of KC. All patients underwent combined wavefront-guided transepithelial photorefractive keratectomy (TPRK) and accelerated corneal collagen cross-linking (ACXL) after intracorneal ring segment (ICRS) implantation. Different measures will be evaluated at baseline, after ICRS implantation, and at one, 3, 6, and 12 months after combined (TPRK and ACXL). These measurements are uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal indices based on Scheimpflug tomography, and higher-order aberrations (HOAs) based on (Sirius, Schwind) tomography.ResultsThere were significant improvements in logMAR (UDVA and CDVA) and reduction in sphere, manifest cylinder, MRSE, maximal keratometry, and mean keratometry after ICRS implantation in the first stage. After TPRK and ACXL as the second stage, there were significant improvements in visual acuity of both logMAR UDVA and CDVA. Reduction in refractive outcomes, including MRSE, sphere, and manifest cylinder. All corneal indices including steep, flat, mean, and maximal keratometries had been decreased. Furthermore, there were significant improvements in the final root mean square, HOAs, and coma aberrations from baseline.ConclusionIn moderate KC, triple therapy of ICRS implantation followed by combined TPRK and ACXL appears to be a safe and effective approach. This approach provides an improvement in visual acuity, refraction, corneal indices, and HOAs. These improvements were maintained for 1 year postoperatively. It also halts KC progression.

Dataset Information

Transepithelial photorefractive keratectomy: a prospective randomized comparative study between the two-step and the single-step techniques.

Objectives

Methods

Results

Conclusion

Clinical trials registry

Publications

Transepithelial photorefractive keratectomy: a prospective randomized comparative study between the two-step and the single-step techniques.

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