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Journal of Cataract and Refractive... Dec 2023Post-keratoplasty (KP) patients' visual acuity can be severely limited by ametropia. Irregular astigmatisms are frequently encountered in these patients and is commonly... (Meta-Analysis)
Meta-Analysis
Post-keratoplasty (KP) patients' visual acuity can be severely limited by ametropia. Irregular astigmatisms are frequently encountered in these patients and is commonly associated with high degrees of hyperopia or myopia. This systematic review investigates the safety and efficacy of laser refractive surgery for post KP vision correction. 31 studies with 683 participants (732 eyes) enrolled in this review. Mean astigmatism improved significantly (mean difference [MD] = -2.70, 95% CI, -3.13 to -2.28, P < .0001). As well as Mean spherical equivalent (MD = -3.35, 95% CI, -3.92 to -2.78, P < .0001). From 586 participants 5.8% lost 2 or more lines of corrected distance visual acuity after treatment. The proportion of eyes with 20/40 uncorrected distance visual acuity or better was reported and the percentage was 46.79% overall. Laser refractive procedures (laser in situ keratomileusis [LASIK] or photorefractive keratectomy [PRK] or transepithelial PRK) on eyes with corneal transplantation were found to be relatively safe and effective. Our systematic review shows there is improvement in all outcomes. Main adverse effects were haze for PRK and epithelial ingrowth for LASIK.
Topics: Humans; Eye; Refraction, Ocular; Vision Tests; Corneal Transplantation; Visual Acuity; Astigmatism
PubMed: 37436139
DOI: 10.1097/j.jcrs.0000000000001256 -
Ophthalmic Research 2023Phototherapeutic keratectomy (PTK) has been increasingly used to treat severe recurrent corneal erosion syndrome (RCES) patients who do not respond to other treatments.... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Phototherapeutic keratectomy (PTK) has been increasingly used to treat severe recurrent corneal erosion syndrome (RCES) patients who do not respond to other treatments. However, the efficacy and complication of each study are currently uncertain due to varying rates.
OBJECTIVES
The objective of this study was to investigate the safety and efficacy of the PTK for recurrent corneal erosions.
METHODS
This article performed a systematic literature research in Cochrane, Embase, PubMed, Scopus, and the Web of Science for the literature on PTK treatment of RCES until December 20, 2022. The extracted data including recurrence rate and the adverse event rate were used for meta-analysis.
RESULTS
The recurrence rate was 18% (95% CI, 13%-24%) (129/700 eyes). Subgroup analysis showed that the RCE recurrence was 17% (95% CI, 9%-24%) after trauma and 22% (95% CI, 11%-32%) in the corneal dystrophy group. Treatment-related adverse events included subepithelial haze, hyperopic shift, and decrease of the best spectacle-corrected visual acuity. In this study, the incidence of these events was 13% (95% CI, 6%-21%), 20% (95% CI, 11%-28%), and 11% (95% CI, 5%-16%), respectively.
CONCLUSIONS
PTK represented a valuable treatment option for patients with recurrent corneal erosions, especially those with traumatic injuries, which had minimal side effects.
Topics: Humans; Lasers, Excimer; Follow-Up Studies; Visual Acuity; Photorefractive Keratectomy; Corneal Dystrophies, Hereditary; Cornea; Corneal Ulcer; Recurrence; Treatment Outcome; Corneal Diseases
PubMed: 37490883
DOI: 10.1159/000533160 -
Journal of Cataract and Refractive... Apr 2020Contradictory results of postoperative steroid application in photorefractive keratectomy (PRK) led to a meta-analysis of the existing data to achieve a definite...
Contradictory results of postoperative steroid application in photorefractive keratectomy (PRK) led to a meta-analysis of the existing data to achieve a definite conclusion on the optimum dosage and duration of corticosteroid therapy after PRK. The overall pooled unstandardized mean difference (PUMD) of the corneal haze score was -0.20 (95% CI, -0.29 to -0.12). In subgroup analysis, the PUMD of the corneal haze score was statistically significant in 2 subgroups, -0.57 (-0.85 to -0.30) for 3 to 6 months postoperatively and -0.13 (-0.23 to -0.04) for ≤ 3 months postoperatively. Analysis of the PUMD of postoperative spherical equivalent in participants with low to moderate myopia (≥-6.00 D) and high myopia (<-6.00 D) showed positive effects of steroids on prevention of myopia regression. In conclusion, long-term topical steroid application after PRK seems unnecessary in low and moderate myopia. New randomized clinical trials using current technologies are recommended for postoperative treatments.
Topics: Administration, Ophthalmic; Alkylating Agents; Glucocorticoids; Humans; Lasers, Excimer; Mitomycin; Ophthalmic Solutions; Photorefractive Keratectomy; Refraction, Ocular; Time Factors; Visual Acuity
PubMed: 32271298
DOI: 10.1097/j.jcrs.0000000000000060 -
Journal of Cataract and Refractive... Jul 2024Laser vision correction for residual refractive errors in patients with previous radial keratotomy (RK) presents a challenging task. Different techniques have been used... (Meta-Analysis)
Meta-Analysis
Laser vision correction for residual refractive errors in patients with previous radial keratotomy (RK) presents a challenging task. Different techniques have been used with varying outcomes. This study aimed to systematically review published articles on refractive surgeries in post-RK patients by conducting a search on PubMed, Scopus, and Web of Science. The final analysis included 35 studies that described a total of 888 eyes. Our systematic review and meta-analysis demonstrated a significant improvement in uncorrected distance visual acuity (UDVA) for photorefractive keratectomy (PRK), topography-guided PRK, wavefront-guided PRK, and femtosecond laser-assisted in situ keratomileusis (LASIK) while mechanical microkeratome LASIK did not yield such significant improvements. Moreover, our results suggest that post-RK patients with hyperopia had a significant improvement in UDVA, whereas no such improvement was observed in patients with myopia.
Topics: Humans; Keratotomy, Radial; Visual Acuity; Refraction, Ocular; Keratomileusis, Laser In Situ; Photorefractive Keratectomy; Lasers, Excimer; Refractive Errors; Myopia; Hyperopia
PubMed: 38353281
DOI: 10.1097/j.jcrs.0000000000001426 -
The Cochrane Database of Systematic... Dec 2020Refractive errors (conditions in which the eye fails to focus objects accurately on the retina due to defects in the refractive system), are the most common cause of... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Refractive errors (conditions in which the eye fails to focus objects accurately on the retina due to defects in the refractive system), are the most common cause of visual impairment. Myopia, hyperopia, and astigmatism are low-order aberrations, usually corrected with spectacles, contact lenses, or conventional refractive surgery. Higher-order aberrations (HOAs) can be quantified with wavefront aberration instruments and corrected using wavefront-guided or wavefront-optimized laser surgery. Wavefront-guided ablations are based on preoperative measurements of HOAs; wavefront-optimized ablations are designed to minimize induction of new HOAs while preserving naturally occurring aberrations. Two wavefront procedures are expected to produce better visual acuity than conventional procedures.
OBJECTIVES
The primary objective was to compare effectiveness and safety of wavefront procedures, laser-assisted in-situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) or laser epithelial keratomileusis (LASEK) versus corresponding conventional procedures, for correcting refractive errors in adults for postoperative uncorrected visual acuity, residual refractive errors, and residual HOAs. The secondary objective was to compare two wavefront procedures.
SEARCH METHODS
We searched the Cochrane Central Register of Controlled Trials (CENTRAL, which contains the Cochrane Eyes and Vision Trials Register; 2019, Issue 8); Ovid MEDLINE; Ovid Embase; Latin American and Caribbean Health Sciences (LILACS); the ISRCTN registry; ClinicalTrials.gov and the WHO ICTRP. The date of the search was 6 August 2019. We imposed no restrictions by language or year of publication. We used the Science Citation Index (September 2013) and searched the reference lists of included trials to identify additional relevant trials.
SELECTION CRITERIA
We included randomized controlled trials (RCTs) comparing either wavefront modified with conventional refractive surgery or wavefront-optimized with wavefront-guided refractive surgery in participants aged ⪰ 18 years with refractive errors.
DATA COLLECTION AND ANALYSIS
We used standard Cochrane methodology.
MAIN RESULTS
We identified 33 RCTs conducted in Asia, Europe and United States, totaling 1499 participants (2797 eyes). Participants had refractive errors ranging from high myopia to low hyperopia. Studies reported at least one of the following review-specific outcomes based on proportions of eyes: with uncorrected visual acuity (UCVA) of 20/20 or better, without loss of one or more lines of best spectacle-corrected visual acuity (BSCVA), within ± 0.50 diopters (D) of target refraction, with HOAs and adverse events. Study characteristics and risk of bias Participants were mostly women, mean age 29 and 53 years, and without previous refractive surgery, ocular pathology or systemic comorbidity. We could not judge risks of bias for most domains of most studies. Most studies in which both eyes of a participant were analyzed failed to account for correlations between two eyes in the analysis and reporting of outcomes. Findings For the primary comparison between wavefront (PRK or LASIK or LASEK) and corresponding conventional procedures, 12-month outcome data were available from only one study of PRK with 70 participants. No evidence of more favorable outcomes of wavefront PRK on proportion of eyes: with UCVA of 20/20 or better (risk ratio [RR] 1.03, 95% confidence interval (CI) 0.86 to 1.24); without loss of one or more lines of BSCVA (RR 0.94, 95% CI 0.81 to 1.09); within ± 0.5 D of target refraction (RR 1.03, 95% CI 0.86 to 1.24); and mean spherical equivalent (mean difference [MD] 0.04, 95% CI -0.11 to 0.18). The evidence for each effect estimate was of low certainty. No study reported HOAs at 12 months. At six months, the findings of two to eight studies showed that overall effect estimates and estimates by subgroup of PRK or LASIK or LASEK were consistent with those for PRK at 12 month, and suggest no difference in all outcomes. The certainty of evidence for each outcome was low. For the comparison between wavefront-optimized and wavefront-guided procedures at 12 months, the overall effect estimates for proportion of eyes: with UCVA of 20/20 or better (RR 1.00, 95% CI 0.99 to 1.02; 5 studies, 618 participants); without loss of one or more lines of BSCVA (RR 0.99, 95% CI 0.96 to 1.02; I = 0%; 5 studies, 622 participants); within ± 0.5 diopters of target refraction (RR 1.02, 95% CI 0.95 to 1.09; I = 33%; 4 studies, 480 participants) and mean HOAs (MD 0.03, 95% CI -0.01 to 0.07; I = 41%; 5 studies, 622 participants) showed no evidence of a difference between the two groups. Owing to substantial heterogeneity, we did not calculate an overall effect estimate for mean spherical equivalent at 12 months, but point estimates consistently suggested no difference between wavefront-optimized PRK versus wavefront-guided PRK. However, wavefront-optimized LASIK compared with wavefront-guided LASIK may improve mean spherical equivalent (MD -0.14 D, 95% CI -0.19 to -0.09; 4 studies, 472 participants). All effect estimates were of low certainty of evidence. At six months, the results were consistent with those at 12 months based on two to six studies. The findings suggest no difference between two wavefront procedures for any of the outcomes assessed, except for the subgroup of wavefront-optimized LASIK which showed probable improvement in mean spherical equivalent (MD -0.12 D, 95% CI -0.19 to -0.05; I = 0%; 3 studies, 280 participants; low certainty of evidence) relative to wavefront-guided LASIK. We found a single study comparing wavefront-guided LASIK versus wavefront-guided PRK at six and 12 months. At both time points, effect estimates consistently supported no difference between two procedures. The certain of evidence was very low for all estimates. Adverse events Significant visual loss or optical side effects that were reported were similar between groups.
AUTHORS' CONCLUSIONS
This review suggests that at 12 months and six months postoperatively, there was no important difference between wavefront versus conventional refractive surgery or between wavefront-optimized versus wavefront-guided surgery in the clinical outcomes analyzed. The low certainty of the cumulative evidence reported to date suggests that further randomized comparisons of these surgical approaches would provide more precise estimates of effects but are unlikely to modify our conclusions. Future trials may elect to focus on participant-reported outcomes such as satisfaction with vision before and after surgery and effects of remaining visual aberrations, in addition to contrast sensitivity and clinical outcomes analyzed in this review.
Topics: Adult; Astigmatism; Corneal Wavefront Aberration; Female; Humans; Hyperopia; Keratectomy, Subepithelial, Laser-Assisted; Keratomileusis, Laser In Situ; Lasers, Excimer; Male; Middle Aged; Myopia; Photorefractive Keratectomy; Randomized Controlled Trials as Topic; Treatment Outcome; Visual Acuity
PubMed: 33336797
DOI: 10.1002/14651858.CD012687.pub2 -
BMC Ophthalmology Aug 2019The aim of this study was to compare the postoperative corneal biomechanical properties between small incision lenticule extraction (SMILE) and other corneal refractive... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The aim of this study was to compare the postoperative corneal biomechanical properties between small incision lenticule extraction (SMILE) and other corneal refractive surgeries.
METHODS
A systematic review and meta-analysis were conducted. Articles from January 2005, to April 2019, were identified searching PubMed, EMBASE, Web of Science, and International Clinical Trials Registry Platform. Studies that compared SMILE with other corneal refractive surgeries on adult myopia patients and evaluated corneal biomechanics were included. Multiple effect sizes in each study were combined. Random-effects model was conducted in the meta-analysis.
RESULTS
Twenty-two studies were included: 5 randomized controlled trials (RCTs), 9 prospective and 6 retrospective cohort studies, and 2 cross-sectional studies. Using the combined effect of corneal hysteresis (CH) and corneal resistance factor (CRF), which were obtained from ocular response analyzer (ORA), the pooled Hedges' g of SMILE versus femtosecond laser-assisted in situ keratomileusis (FS-LASIK) was 0.41 (95% CI, 0.00 to 0.81; p = 0.049; I = 78%), versus LASIK was 1.31 (95% CI, 0.54 to 2.08; p < 0.001; I = 77%), versus femtosecond lenticule extraction (FLEX) was - 0.01 (95% CI, - 0.31 to 0.30; p = 0.972; I = 20%), and versus the group of photorefractive keratectomy (PRK) and laser-assisted sub-epithelial keratectomy (LASEK) was - 0.26 (95% CI, - 0.67 to 0.16; p = 0.230; I = 54%). The summary score of Corvis ST (CST) after SMILE was comparable to FS-LASIK/LASIK with the pooled Hedges' g = - 0.05 (95% CI, - 0.24 to 0.14; p = 0.612, I = 55%).
CONCLUSIONS
In terms of preserving corneal biomechanical strength after surgeries, SMILE was superior to either FS-LASIK or LASIK, while comparable to FLEX or PRK/LASEK group based on the results from ORA. More studies are needed to apply CST on evaluating corneal biomechanics after refractive surgeries.
Topics: Biomechanical Phenomena; Cornea; Humans; Keratectomy, Subepithelial, Laser-Assisted; Keratomileusis, Laser In Situ; Myopia; Photorefractive Keratectomy; Postoperative Period; Refraction, Ocular; Visual Acuity
PubMed: 31370817
DOI: 10.1186/s12886-019-1165-3 -
Eye & Contact Lens Nov 2023This study systematically reviewed the performance of bandage contact lenses (BCL) such as lotrafilcon A, lotrafilcon B, senofilcon A, balafilcon A, and comfilcon A as...
This study systematically reviewed the performance of bandage contact lenses (BCL) such as lotrafilcon A, lotrafilcon B, senofilcon A, balafilcon A, and comfilcon A as postoperative treatment in different ocular surgeries. A systematic search of English and Chinese databases (from inception to December 2021) was conducted for studies reporting the efficacy of BCLs after ocular surgeries. Postoperative symptoms, corneal healing, and visual outcomes were studied. Overall, 38 studies were identified. Bandage contact lens was applied as a postoperative aid in corneal refractive, cataract, and vitrectomy surgeries. Most studies were on photorefractive keratectomy. Reduced postoperative symptoms were observed within 4 hr to 3 days, whereas re-epithelization of the cornea and healing was complete within 3 to 7 days after ocular surgeries except for vitrectomy. In a vitrectomy, greater comfort and improved corneal epithelium were observed on the seventh day after surgery. An improvement in dry eye symptoms was observed at 7 days with considerable benefits observed after 1 month of cataract surgery. These findings indicate that BCLs are effective for improving postoperative symptoms and facilitation of early visual rehabilitation with a wear time of 8 hr to 7 days depending on the type of ocular surgery.
Topics: Humans; Ophthalmology; Bandages, Hydrocolloid; Contact Lenses, Hydrophilic; Photorefractive Keratectomy; Cataract
PubMed: 37816246
DOI: 10.1097/ICL.0000000000001021 -
Journal of Refractive Surgery... Oct 2018To evaluate the outcomes of simultaneous and sequential corneal crosslinking (CXL) and excimer laser surface ablation protocols in keratoconus. (Comparative Study)
Comparative Study
PURPOSE
To evaluate the outcomes of simultaneous and sequential corneal crosslinking (CXL) and excimer laser surface ablation protocols in keratoconus.
METHODS
A literature review was conducted using MEDLINE. The studies were divided into three groups: the sequential group included studies with CXL followed by excimer laser surface ablation later, the simultaneous group included simultaneous excimer laser surface ablation and CXL, and the no CXL group included excimer laser surface ablation only with no CXL. The data on change in logMAR uncorrected distance visual acuity (UDVA), spectacle corrected distance visual acuity (CDVA), change in spherical equivalent (SE) and refractive astigmatism, change in maximum keratometry (Kmax), complications, and safety and efficacy indices were presented for the latest follow-up visits in all groups.
RESULTS
Twenty-one studies (3 = sequential; 11 = simultaneous, 7 = no CXL) were included. UDVA improved in all groups. CDVA improved more in the sequential group. SE change was greatest in the no CXL group and the refractive astigmatism reduced comparably in the sequential and no CXL groups but less in the simultaneous group. Kmax reduced in all groups. Only the sequential group showed no progression. Corneal haze was reported in 100%, 54.5%, and 57.1% studies, respectively. Safety and efficacy indices were 1.96 and 1.58, 1.41 ± 0.32 and 0.91 ± 0.41, and 1 and 0.82, respectively.
CONCLUSIONS
The sequential group showed greater improvement in CDVA, SE, and refractive astigmatism. Corneal haze was frequently reported in all protocols. Safety and efficacy indices were highest when CXL was performed before excimer laser and least when excimer laser was performed alone without CXL. [J Refract Surg. 2018;34(10):690-696.].
Topics: Collagen; Corneal Pachymetry; Corneal Stroma; Cross-Linking Reagents; Humans; Keratoconus; Lasers, Excimer; Photochemotherapy; Photorefractive Keratectomy; Photosensitizing Agents; Refraction, Ocular; Riboflavin; Ultraviolet Rays; Visual Acuity
PubMed: 30296330
DOI: 10.3928/1081597X-20180824-01