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1,956 result(s) for "Photorefractive Keratectomy"
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Transepithelial photorefractive keratectomy for low to moderate myopia in comparison with conventional photorefractive keratectomy
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 pain scores in favor of the tPRK group (P = 0.04). The tPRK group had a shorter epithelial healing time than the conventional PRK group postoperatively (P = 0.01). Mean UCVA was significantly better in the case group than in the control group at the postoperative month 2 (P = 0.01). Regarding the safety and efficacy indexes, the tPRK group had better results than the conventional PRK group (P < 0.01 for both comparisons). Conclusion: Transepithelial PRK seems to be superior to conventional PRK for treatment of low to moderate myopia in terms of postoperative pain, epithelial healing time, visual recovery and safety and efficacy indexes.
Efficacy of single-step transepithelial photorefractive keratectomy in myopia, hyperopia and astigmatism-a systematic review
Background This systematic review assesses the efficacy of single-step transepithelial photorefractive keratectomy (tPRK) in terms of postoperative pain, epithelial healing, postoperative haze and visual acuity. It also compares single tPRK to two-step tPRK where data is available. Methods This systematic review adhered to the PRISMA reporting guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses). An electronic literature search was conducted on PUBMED, Scopus, and Google Scholar. The quality of the studies included in this systematic review was evaluated using the Newcastle Ottawa Scale (NOS). The protocol of this systematic review was registered on PROSPERO with ID CRD42024494717. Results A total of 11 studies published between 2013 and 2023 were included in this systematic review. Studies revealed a significant improvement in visual acuity with both single-step tPRK and two-step tPRK. Two studies showed that single-step tPRK not only offers a better UDVA but also a significant improvement in the manifest sphere, cylinder, and spherical equivalent at various follow-up periods compared to two-step tPRK. One study demonstrated the broad effectiveness of single-step tPRK for myopia correction across low-, moderate-, and high-severity groups. Rapid epithelial healing was a consistent finding. Complete epithelial healing within 72 h was noted in 100% of eyes treated with single-step tPRK in one of the studies. The incidence of corneal haze following tPRK was generally low across the studies. Post-tPRK pain scores were initially lower in the single-step tPRK group. One study reported that the maximum pain level within the first four days after surgery was significantly lower in the single-step tPRK group than in the two-step tPRK group. Conclusion Both two-step and single-step tPRK are safe refractive procedures. Single-step tPRK, because of less haze formation, lower pain scores, faster healing, and greater effectiveness in improving visual acuity, is superior to the two-step technique. Trial registration The protocol of this systematic review was registered on PROSPERO with ID CRD42024494717.
Base curves of bandage contact lenses and their effects on post Trans-PRK vision and pain: the study protocol for a randomized clinical trial
Background Transepithelial photorefractive keratectomy (Trans-PRK) is an effective and safe laser surgery for myopia. Following this procedure, a bandage contact lens is used to promote epithelial healing, reduce postoperative pain, and improve visual recovery. The base curve of these lenses may affect vision post-surgery, particularly in patients with steep corneas and high myopia. This study aims to investigate the impact of using bandage contact lenses with base curves of 8.4 mm versus 8.8 mm on visual recovery after Trans-PRK in patients with steep corneas and high myopia. Methods This is a randomized, double-blind, binocularly controlled, single-center trial. The study subjects are myopic patients scheduled for Trans-PRK. Both eyes in each patient will be treated consecutively with single-step Trans-PRK. After surgery, a contact lens with an 8.8-mm base curve will be placed on one eye, and a lens with an 8.4-mm base curve will be placed on the other. The primary objective is to determine the difference in early postoperative uncorrected visual acuity between the two eyes of patients with steep corneas and high myopia. Randomization will be conducted using a computer-generated random allocation sequence without blocks or restrictions. The sequence will be recorded in sealed opaque envelopes, maintained by the principal investigator until the trial’s conclusion. In this double-masked trial, subjects will not know which treatment each eye receives. Discussion This novel trial will provide information on how bandage contact lenses with different base curves promote epithelial healing and visual recovery after Trans-PRK, thus offering evidence for clinical practice. Trial registration ClinicalTrials.gov NCT06393855. Registered on May 1, 2024. https://clinicaltrials.gov/study/NCT06393855 .
Refractive surgery and dry eye - An update
Dry eye disease is the most common complication and a frequent cause of patient dissatisfaction after corneal laser refractive surgery, which includes laser-assisted in situ keratomileusis (LASIK), small-incision lenticule extraction (SMILE), and photorefractive keratectomy (PRK). It has a complex, multifactorial etiology and is characterized by a highly variable clinical presentation. A detailed preoperative screening and optimization of the ocular surface prior to refractive surgery are the key to minimizing the incidence and severity of postoperative dry eye. Diagnosis of postrefractive surgery dry eye remains a challenge as no single symptom or clinical parameter is confirmative of the condition, and the symptoms and signs may not correlate well in many cases. A thorough understanding of the pathomechanism of the disease and its manifestations is essential to facilitate a treatment approach that is individualized for each patient. This article reviews various aspects of postrefractive surgery dry eye including its epidemiology, etiopathogenesis, risk factors, diagnosis, and management.
Applications of Mitomycin C in Cornea and External Disease
Isolated from Streptomyces caespitosus, mitomycin C (MMC) has various applications in the management of corneal and external disease due to its ability to modulate cellular proliferation. It has been employed in pterygium surgery, ocular surface neoplasia, and refractive surgery. Currently, there is no definite consensus on the treatment protocols for each of the aforementioned applications. Although its benefits in the management of corneal and external diseases are promising, MMC use has potential complications including endothelial cell loss, corneal perforation, scleral melt, secondary glaucoma, iritis, and endophthalmitis. This article will review the literature regarding the use of MMC in the field of cornea and external disease and describe protocols employed with corresponding outcomes. Keywords: Mitomycin C, pterygium surgery, photorefractive keratectomy scar, post-PRK haze
Single-step Transepithelial photorefractive keratectomy in the treatment of mild, moderate, and high myopia: six month results
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.
Ten-Year Outcomes of Progressive Keratoconus Management With the Athens Protocol (Topography-Guided Partial-Refraction PRK Combined With CXL)
To report the safety and long-term efficacy of topography-guided partial-refraction PRK combined with corneal cross-linking (CXL) (the Athens Protocol), refractive, topographic, and pachymetric changes of keratoconic eyes treated were studied. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, keratometry, qualitative and quantitative assessment of corneal keratometric, and pachymetric properties recorded by topography and tomography were evaluated for 10 years postoperatively. A total of 144 eyes were followed up for a mean 128 ± 4 months (range: 120 to 146 months). Mean UDVA markedly improved at 1 year (0.19 ± 0.17 to 0.53 ± 0.21 decimal) with further improvement to 0.55 ± 0.19 decimal at 10 years. CDVA increased from 0.59 ± 0.21 to 0.80 ± 0.17 decimal at 1 year and further to 0.81 ± 0.19 decimal at 10 years. Corneal thickness decreased from 468.74 ± 35.05 to 391.14 ± 40.07 μm at 1 year (P < .01) and up to 395.42 ± 32.21 μm at 10 years. Steep keratometry decreased from 50.57 ± 2.80 to 45.87 ± 2.70 diopters (D) (P < .01) at 1 year and to 44.00 ± 3.22 D at 10 years. Maximum keratometry decreased from 53.43 ± 2.97 to 46.17 ± 1.18 D at 1 year and 44.75 ± 2.14 D at 10 years (P < .01). A total of 94.4% demonstrated ectasia stabilization and 3.5% showed progressive \"overcorrection\" or \"hyperopic\" shift. The Athens Protocol confirms long-term safety and efficacy for corneal ectasia and visual function. Most parameters had little change after 1 year, through year 10. [J Refract Surg. 2019;35(8):478-483.].
Does the introduction of streamlight decrease refractive surgery operating time?
PurposeThe aim of the study was to analyze the time-savings associated with introduction of Streamlight™ (Alcon Laboratories, Fort Worth, TX, USA) transepithelial photorefractive keratectomy (PRK) in surface corneal ablations.MethodsAll refractive surgeries were performed using the Alcon WaveLight® EX500 at the ArtLife Clinic, Gdańsk, Poland. The study included patients treated for refractive errors with transepithelial PRK between April 2019 and October 2021, who were matched with patients treated with alcohol-assisted PRK during the same period. Only results for the left eye were analyzed.ResultsOne-hundred-five patients underwent transepithelial PRK (age 33.42 ± 8.67 years) and were matched with 105 patients that underwent alcohol-assisted PRK (age 33.05 ± 10.16 years; p = 0.11). The mean preoperative spherical equivalent refraction was − 2.04 ± 2.28 D, and − 1.9 ± 1.71 D for the transepithelial and alcohol-assisted PRK group, respectively (p = 0.20). The total surgery time was non-significantly shorter in transepithelial PRK (349.46 ± 47.83 s) than in alcohol-assisted PRK (354.93 ± 137.63 s; p = 0.7); however, the variance of surgical time was significantly lower in transepithelial PRK (p < 0.001). The laser treatment duration was greater in transepithelial PRK (41.78 ± 17.2 s) than in alcohol-assisted PRK (8.48 ± 6.12 s; p < 0.001), and so was the number of breaks during the laser treatment (0.95 ± 0.63 vs. 0.53 ± 0.88, respectively; p < 0.001).ConclusionThe introduction of transepithelial PRK did not bring significant time-associated savings into the refractive surgery suite.
Comparison of transepithelial and conventional photorefractive keratectomy in myopic and myopic astigmatism patients: a randomized contralateral trial
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 in conventional PRK groups compared to tPRK (both P <0.001) in both arms. However, there was no significant difference in safety, efficacy, spherical equivalent refractive accuracy, or corneal haze development between tPRK and conventional PRK groups (all P  > 0.05). Conclusions All three methods are effective in terms of visual and refractive outcomes. However, although time to complete re-epithelialization was similar with the three methods, the epithelial healing rate was faster in conventional PRK considering the initial corneal epithelial defect area, and the patients experienced less pain and discomfort in the first postoperative day. Trial registration IRCT, IRCT20200317046804N1 . Retrospectively registered 5 May 2020.
Comparison of objective and subjective visual quality after flapless laser vision correction for mild to moderate myopia: SMILE vs PRK
PurposeTo investigate the differences in surgical results and the objective and subjective quality of vision (QoV) of patients after small incision lenticule extraction (SMILE) versus alcohol-assisted photorefractive keratectomy (PRK).MethodsMedical records of patients treated with SMILE and PRK were retrospectively examined. Visual quality, biometric parameters, Strehl ratio (SR), and corneal higher-order aberrations (HOAs) within a 6.0 mm area were recorded. The effective optical zone (EOZ) and decentration were measured using a tangential pre-post operation difference map. Subjective QoV and operation satisfaction were evaluated 6 months postoperatively using the Quality of Vision questionnaire.ResultsThe study comprised 100 eyes treated with SMILE (preoperative mean spherical equivalent (SE), − 4.52 ± 0.81 dioptres (D)) and 69 eyes with PRK (mean SE, − 4.21 ± 1.25 D). Six months postoperatively, the EOZ reduction was significantly larger in the PRK group (P < 0.001). Decentrations were comparable between the groups. Regarding visual symptoms, monocular diplopia was more common following PRK (P = 0.02), and 98 (98.00%) SMILE-treated and 67 (97.10%) PRK-treated patients were satisfied with the QoV. Both groups demonstrated significant increases in total HOAs, coma, and spherical aberration (SA) at 6 months postoperatively compared to preoperatively (P < 0.001); these values were significantly higher in the PRK (P < 0.05) compared to the SMILE group. SR increased significantly only in the PRK group (P < 0.05).ConclusionAlthough EOZ was more consistent with anticipated treatment and HOAs were fewer in SMILE, high patient-reported satisfaction and good corneal optical quality were achieved in both groups, indicating that both SMILE and alcohol-assisted PRK are excellent options for mild to moderate myopia correction.