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Canadian Journal of Ophthalmology.... Dec 2018To evaluate the indications and outcomes of manual blade superficial keratectomy STUDY DESIGN: Retrospective, nonrandomized, consecutive case series METHODS: Database... (Observational Study)
Observational Study
INTRODUCTION
To evaluate the indications and outcomes of manual blade superficial keratectomy STUDY DESIGN: Retrospective, nonrandomized, consecutive case series METHODS: Database search of patients from 2012-2017 who underwent superficial keratectomy was conducted at a tertiary care hospital cornea clinic. Charts of 121 patients (156 eyes) were reviewed who had at least 4 weeks of follow-up and both preoperative and postoperative measurements of best-corrected visual acuity or corneal cylinder. Outcome measures included: patient demographics, surgical indication, prior ocular history, best-corrected visual acuity (BCVA) changes, corneal and refractive astigmatism changes, recurrence of pathology, additional treatments required, and intraoperative and postoperative complications.
RESULTS
Mean patient age at time of operation was 63.3 (±14.8), 39% were male. Indications included epithelial basement membrane dystrophy, recurrent corneal erosion syndrome, Salzmann nodular degeneration, band keratopathy, and suspected ocular surface neoplasia. In eyes with epithelial basement membrane dystrophy, mean BCVA (20/47 to 20/40, P = 0.033), refractive astigmatism (1.76 ± 1.83 D to 1.15 ± 1.08 D, P = 0.010), and corneal astigmatism (1.44 ± 0.88 D to 1.06 ± 0.88 D, P = 0.022) significantly improved. Twenty-four percent (5/21) of eyes with recurrent erosions had symptoms return at a mean 6.5 months follow-up. No intraoperative complications were noted. The epithelium healed completely in all 156 eyes at final follow-up.
CONCLUSION
Superficial keratectomy is a simple, safe procedure that can be performed for a variety of conditions to improve visual acuity, reduce corneal astigmatism, and alleviate symptoms secondary to ocular surface pathology.
Topics: Aged; Cornea; Corneal Diseases; Corneal Topography; Female; Follow-Up Studies; Humans; Lasers, Excimer; Male; Middle Aged; Photorefractive Keratectomy; Retrospective Studies; Treatment Outcome; Visual Acuity
PubMed: 30502977
DOI: 10.1016/j.jcjo.2018.01.030 -
Indian Journal of Ophthalmology Dec 2020
Topics: Corneal Stroma; Humans; Lasers, Excimer; Photorefractive Keratectomy
PubMed: 33229633
DOI: 10.4103/ijo.IJO_2543_20 -
Journal of Cataract and Refractive... Jul 2021To compare the elastic modulus of thin corneal lamellas using 2D stress-strain extensometry in healthy ex vivo human corneal lamellas with or without the presence of...
PURPOSE
To compare the elastic modulus of thin corneal lamellas using 2D stress-strain extensometry in healthy ex vivo human corneal lamellas with or without the presence of Bowman layer.
SETTING
Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Switzerland; ELZA Institute, Dietikon, Switzerland; Department of Ophthalmology, Philipps University of Marburg, Germany.
DESIGN
Prospective experimental laboratory study.
METHODS
Healthy human corneas were stripped of Descemet membrane and the endothelium for Descemet membrane endothelial keratoplasty. After epithelium removal, corneas were divided into 2 groups. In Group 1, Bowman layer was ablated with an excimer laser (20 μm thick, 10 mm). In Group 2, Bowman layer was left intact. Then, a lamella was cut from the anterior cornea with an automated microkeratome. Elastic and viscoelastic material properties were analyzed by 2D stress-strain extensometry between 0.03 and 0.70 N.
RESULTS
Twenty-six human corneas were analyzed. The mean lamella thickness was 160 ± 37 μm in corneas with Bowman layer and 155 ± 22 μm in corneas without. No statistically significant differences between flaps with and without Bowman layer were observed in the tangential elastic modulus between 5% and 20% strain (11.5 ± 2.9 kPa vs 10.8 ± 3.7 kPa, P > .278).
CONCLUSIONS
The presence or absence of Bowman layer did not reveal a measurable difference in corneal stiffness. This may indicate that the removal of Bowman layer during photorefractive keratectomy does not represent a disadvantage to corneal biomechanics.
Topics: Biomechanical Phenomena; Cornea; Germany; Humans; Photorefractive Keratectomy; Prospective Studies
PubMed: 33315734
DOI: 10.1097/j.jcrs.0000000000000543 -
The Cochrane Database of Systematic... Feb 2016Myopia (near-sightedness or short-sightedness) is a condition in which the refractive power of the eye is greater than required. The most frequent complaint of people... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Myopia (near-sightedness or short-sightedness) is a condition in which the refractive power of the eye is greater than required. The most frequent complaint of people with myopia is blurred distance vision, which can be eliminated by conventional optical aids such as spectacles or contact lenses, or by refractive surgery procedures such as photorefractive keratectomy (PRK) and laser epithelial keratomileusis (LASEK). PRK uses laser to remove the corneal stroma. Similar to PRK, LASEK first creates an epithelial flap and then replaces it after ablating the corneal stroma. The relative benefits and harms of LASEK and PRK, as shown in different trials, warrant a systematic review.
OBJECTIVES
The objective of this review is to compare LASEK versus PRK for correction of myopia by evaluating their efficacy and safety in terms of postoperative uncorrected visual acuity, residual refractive error, and associated complications.
SEARCH METHODS
We searched CENTRAL (which contains the Cochrane Eyes and Vision group Trials Register) (2015 Issue 12), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to December 2015), EMBASE (January 1980 to December 2015), Latin American and Caribbean Health Sciences (LILACS) (January 1982 to December 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 15 December 2015. We used the Science Citation Index and searched the reference lists of the included trials to identify relevant trials for this review.
SELECTION CRITERIA
We included in this review randomized controlled trials (RCTs) comparing LASEK versus PRK for correction of myopia. Trial participants were 18 years of age or older and had no co-existing ocular or systemic diseases that might affect refractive status or wound healing.
DATA COLLECTION AND ANALYSIS
Two review authors independently screened all reports and assessed the risk of bias of trials included in this review. We extracted data and summarized findings using risk ratios and mean differences. We used a random-effects model when we identified at least three trials, and we used a fixed-effect model when we found fewer than three trials.
MAIN RESULTS
We included 11 RCTs with a total of 428 participants 18 years of age or older with low to moderate myopia. These trials were conducted in the Czech Republic, Brazil, Italy, Iran, China, Korea, Mexico, Turkey, USA, and UK. Investigators of 10 out of 11 trials randomly assigned one eye of each participant to be treated with LASEK and the other with PRK, but did not perform paired-eye (matched) analysis. Because of differences in outcome measures and follow-up times among the included trials, few trials contributed data for many of the outcomes we analyzed for this review. Overall, we judged RCTs to be at unclear risk of bias due to poor reporting; however, because of imprecision, inconsistency, and potential reporting bias, we graded the quality of the evidence from very low to moderate for outcomes assessed in this review.The proportion of eyes with uncorrected visual acuity of 20/20 or better at 12-month follow-up was comparable in LASEK and PRK groups (risk ratio (RR) 0.98, 95% confidence interval (95% CI) 0.92 to 1.05). Although the 95% CI suggests little to no difference in effect between groups, we judged the quality of the evidence to be low because only one trial reported this outcome (102 eyes). At 12 months post treatment, data from two trials suggest no difference or a possibly small effect in favor of PRK over LASEK for the proportion of eyes achieving ± 0.50 D of target refraction (RR 0.93, 95% CI 00.84 to 1.03; 152 eyes; low-quality evidence). At 12 months post treatment, one trial reported that one of 51 eyes in the LASEK group lost one line or more best-spectacle corrected visual acuity compared with none of 51 eyes in the PRK group (RR 3.00, 95% CI 0.13 to 71.96; very low-quality evidence).Three trials reported adverse outcomes at 12 months of follow-up or longer. At 12 months post treatment, three trials reported corneal haze score; however, data were insufficient and were inconsistent among the trials, precluding meta-analysis. One trial reported little or no difference in corneal haze scores between groups; another trial reported that corneal haze scores were lower in the LASEK group than in the PRK group; and one trial did not report analyzable data to estimate a treatment effect. At 24 months post treatment, one trial reported a lower, but clinically unimportant, difference in corneal haze score for LASEK compared with PRK (MD -0.22, 95% CI -0.30 to -0.14; 184 eyes; low-quality evidence).
AUTHORS' CONCLUSIONS
Uncertainty surrounds differences in efficacy, accuracy, safety, and adverse effects between LASEK and PRK for eyes with low to moderate myopia. Future trials comparing LASEK versus PRK should follow reporting standards and follow correct analysis. Trial investigators should expand enrollment criteria to include participants with high myopia and should evaluate visual acuity, refraction, epithelial healing time, pain scores, and adverse events.
Topics: Adult; Humans; Keratectomy, Subepithelial, Laser-Assisted; Myopia; Photorefractive Keratectomy; Randomized Controlled Trials as Topic; Time Factors; Visual Acuity
PubMed: 26899152
DOI: 10.1002/14651858.CD009799.pub2 -
Cornea Mar 2016
Topics: Corneal Dystrophies, Hereditary; Corneal Opacity; Corneal Surgery, Laser; Female; Humans; Lasers, Excimer; Male; Photorefractive Keratectomy
PubMed: 26840597
DOI: 10.1097/ICO.0000000000000749 -
Journal of Medicine and Life 2020Refractive eye surgeries are one of the most non-emergent ophthalmic surgeries due to the effect on the reduction of refractive errors, increasing visual acuity,...
Refractive eye surgeries are one of the most non-emergent ophthalmic surgeries due to the effect on the reduction of refractive errors, increasing visual acuity, enhancing the quality of vision, and indirectly increasing the quality of life of patients. The aim of this study was to determine Pentacam indices in the patients who underwent photorefractive keratectomy (PRK) during 2014-2018, as well as to show their correlation with the type of refractive error. This descriptive cross-sectional study was performed on 2215 eyes of 1125 patients undergoing PRK surgery. The patients' checklist, including demographic information, refractive index, keratometry, pachymetry, corneal surface zone indices, and progressive corneal thickness indices, was provided. All data were analyzed using the IBM SPSS software, version 25. The findings showed that there was a significant association between posterior corneal astigmatism (PCA) and anterior corneal astigmatism (ACA) (p=0.00). The mean Kmax front was recorded as 44.844 ± 1.58 D, which was significantly correlated with the type of refractive errors (p=0.00). According to the findings, there was a significant relationship between anterior chamber indices and refractive error types and their severity (p=0.00). There was also a significant correlation between the surface zone and keratoconus indices (i.e., index of surface variance - ISV, index of vertical asymmetry - IVA, index of height asymmetry - IHA, and minimum radius of curvature - Rmin) with refractive errors (p=0.00). The findings showed that some of the Pentacam indices could be related to the types of refractive errors in patients undergoing PRK surgery. Therefore, their evaluation is of great importance in this regard.
Topics: Adult; Astigmatism; Corneal Pachymetry; Cross-Sectional Studies; Female; Humans; Male; Photorefractive Keratectomy; Quality of Life; Visual Acuity
PubMed: 33456601
DOI: 10.25122/jml-2020-0057 -
Journal of Cataract and Refractive... Jul 2019To evaluate the effect of a bandage contact lens soaked in ketorolac ophthalmic 0.45% solution (Acuvail) on pain modulation in patients having transepithelial... (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
To evaluate the effect of a bandage contact lens soaked in ketorolac ophthalmic 0.45% solution (Acuvail) on pain modulation in patients having transepithelial photorefractive keratectomy (PRK).
DESIGN
Prospective case series.
SETTING
Narayana Nethralaya Superspeciality Eye Hospital, Bangalore, India.
METHODS
Eyes of patients were divided into 2 groups. After transepithelial PRK, a regular soft bandage contact lens was placed in Group 1 and a ketorolac-soaked bandage contact lens was placed in Group 2. The patients were matched for age and sex in the 2 groups. Postoperative pain was compared using the validated Wong-Baker pain scale. Before placement of a ketorolac-soaked bandage contact lens in patients' eyes, the safety of the procedure was checked using cultures from the bandage contact lens and measuring the quantity of the drug adsorbed and the elution profile over time with ultra-high-performance liquid chromatography (UHPLC).
RESULTS
Each group comprised 35 eyes of 35 patients. The mean pain score was 7.95 ± 2.12 (SD) in Group 1, which was significantly higher than in Group 2 (2.76 ± 0.85), which received the ketorolac-soaked bandage contact lens. The UHPLC results showed that the soaked bandage contact lens acted as a depot for ketorolac, which was released onto the ocular surface over time, providing postoperative pain relief without causing adverse events.
CONCLUSION
A bandage contact lens soaked in ketorolac 0.45% solution can act as a potential drug depot that can reduce pain after transepithelial PRK.
Topics: Anti-Inflammatory Agents, Non-Steroidal; Bandages, Hydrocolloid; Contact Lenses, Hydrophilic; Female; Humans; Ketorolac; Lasers, Excimer; Male; Myopia; Pain Management; Pain Measurement; Pain, Postoperative; Photorefractive Keratectomy; Prospective Studies; Treatment Outcome; Young Adult
PubMed: 31029475
DOI: 10.1016/j.jcrs.2019.01.032 -
Journal of Refractive Surgery... May 2024To report on the prospective evaluation of photorefractive keratectomy (PRK) in experienced ametropic naval aviators that led to the approval of refractive surgery for...
PURPOSE
To report on the prospective evaluation of photorefractive keratectomy (PRK) in experienced ametropic naval aviators that led to the approval of refractive surgery for military pilots.
METHODS
This was the first study evaluating refractive surgery in naval aviators. Return to flight status after PRK and clinical outcomes and subjective and objective flight performance were evaluated.
RESULTS
A total of 785 U.S. naval aviators were enrolled in the study. Average preoperative refraction was -2.92 ± 1.73 diopters (D) (range: +5.25 to -9.13 D). By 6 months, 85.9% of eyes were within ±0.50 D and 96.4% were within ±1.00 D of emmetropia. 94.4% of eyes achieved 20/20 or better, 74.3% had 20/16 or better, and 45.2% had 20/12.5 or better uncorrected distance visual acuity (UDVA) at 6 months. A total of 78.5% of aviators met return-to-flight criteria by 4 weeks, 83.3% by 8 weeks, and 90.8% by 12 weeks following PRK. All aviators eventually returned to full flight status. Cumulative flight experience included logging more than 48,000 flight hours and 19,500 landings in the 6 months following PRK. Psychometric questionnaire results showed that 78% reported improved ability to detect other aircraft and 92% reported improved ability to land on an aircraft carrier (82% significantly improved) compared to wearing corrective lenses. No one felt their vision was worse in these dynamic environments. All aviators indicated they would undergo the procedure again and would recommend it to a fellow aviator.
CONCLUSIONS
This prospective study in U.S. naval aviators determined PRK to be safe and effective in a unique patient population operating in a visually demanding and hazardous environment. The program continues to be enthusiastically supported by aviators and PRK is now allowed in all branches of the military and for National Aeronautics and Space Administration astronauts. .
Topics: Photorefractive Keratectomy; Humans; Prospective Studies; Military Personnel; Visual Acuity; Adult; Male; United States; Female; Myopia; Lasers, Excimer; Refraction, Ocular; Young Adult; Middle Aged; Aerospace Medicine; Treatment Outcome
PubMed: 38848054
DOI: 10.3928/1081597X-20240422-02 -
Journal of Cataract and Refractive... Apr 2019To compare the outcomes of transepithelial photorefractive intrastromal corneal crosslinking (CXL) and photorefractive keratectomy (PRK) in eyes with low myopia. (Comparative Study)
Comparative Study
PURPOSE
To compare the outcomes of transepithelial photorefractive intrastromal corneal crosslinking (CXL) and photorefractive keratectomy (PRK) in eyes with low myopia.
SETTING
Purpan Hospital, Toulouse, France.
DESIGN
Prospective case series.
METHODS
Myopic patients with a manifest refraction spherical equivalent (MRSE) of -1.00 to -2.50 diopters (D) and a cylindrical component of plano to -0.75 D were included. The dominant eye had PRK (PRK eyes). The nondominant eye had transepithelial photorefractive intrastromal CXL with riboflavin (ParaCel Part 1 and 2), 30 mW/cm pulsed ultraviolet-A irradiation centered on the pupil (Mosaic System) for 16 minutes and 40 seconds, and a supplemental oxygen delivery mask (CXL eyes). The primary outcome measure was the change in the MRSE. Other outcome measures were the uncorrected (UDVA) and corrected (CDVA) distance visual acuities, mean keratometry, and endothelial cell count (ECC) over a 6-month follow-up. Adverse events were assessed.
RESULTS
Nineteen patients were included. By 6 months, the mean MRSE had decreased by 0.72 D ± 0.42 (SD) in CXL eyes and by 1.35 ± 0.46 D in PRK eyes (P < .001). The mean change in UDVA was -0.35 ± 0.21 logarithm of the minimum angle of resolution (logMAR) in CXL eyes and -0.66 ± 0.19 logMAR in PRK eyes (P < .001). No complications were reported. The change in the ECC and CDVA was not statistically significant.
CONCLUSIONS
Photorefractive keratectomy provided better visual and refractive outcomes than transepithelial photorefractive intrastromal CXL. Transepithelial photorefractive intrastromal CXL, however, showed the potential refractive effect of CXL but with a limited magnitude of myopic correction.
Topics: Adult; Corneal Stroma; Corneal Topography; Cross-Linking Reagents; Epithelium, Corneal; Female; Follow-Up Studies; Humans; Male; Myopia; Photochemotherapy; Photorefractive Keratectomy; Photosensitizing Agents; Pilot Projects; Prospective Studies; Refraction, Ocular; Riboflavin; Visual Acuity
PubMed: 30733107
DOI: 10.1016/j.jcrs.2018.11.008 -
Archivos de La Sociedad Espanola de... Feb 2023More than 25 years of experience with refractive surgery techniques (since the FDA [Food and Drug Administration] of the United States approved the use of the excimer... (Review)
Review
More than 25 years of experience with refractive surgery techniques (since the FDA [Food and Drug Administration] of the United States approved the use of the excimer laser in the remodeling of the cornea in 1995), added to the technological advances in ophthalmology (femtosecond laser, topography-guided ablation, anterior segment imaging systems) and increased understanding of refractive errors, higher order aberrations, and corneal biomechanics make corneal laser refractive surgery a safe method and effective for the correction of these defects. However, to date, there are still certain circumstances that represent a contraindication for its application, in addition to others that could be associated with complications, and that must be carefully analyzed. This review analyzes the current contraindications for laser corneal refractive surgery listed in the Preferred Practice Protocols (PPPs) of the American Academy of Ophthalmology and the Spanish Ophthalmology Society. These protocols are based on the best scientific evidence currently available and allow clear recommendations to be drawn, improving the safety profile of these techniques. Contraindications can be differentiated into relative or absolute; among the latter are: age less than 18 years, the absence of refractive stability and the existence of certain ocular pathologies (including certain corneal dystrophies, keratoconus, poorly controlled dry eye) or systemic pathologies (active autoimmune processes or poorly controlled diabetes mellitus). Other circumstances such as the use of certain drugs (amiodarone, isotretinoin), extreme values of mean central keratometry and pachymetry, history of previous uveitis or glaucoma, pregnancy and lactation, are considered relative contraindications according to the PPPs. However, there are studies that demonstrate the safety of refractive surgery in some of these cases.
Topics: Pregnancy; Female; Humans; Photorefractive Keratectomy; Keratomileusis, Laser In Situ; Cornea; Lasers, Excimer; Contraindications
PubMed: 36114139
DOI: 10.1016/j.oftale.2022.07.003