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Indian Journal of Ophthalmology Dec 2020Photorefractive keratectomy (PRK) eye surgery is widely used for patients at risk for corneal ectasia to maintain an aspheric corneal shape. Wavefront-guided (WFG)... (Meta-Analysis)
Meta-Analysis Review
Photorefractive keratectomy (PRK) eye surgery is widely used for patients at risk for corneal ectasia to maintain an aspheric corneal shape. Wavefront-guided (WFG) ablation profile was designed to reduce pre-existing higher-order aberrations (HOA). We aimed to compare the corneal aberrations and visual outcomes between WFG and Wavefront Optimized (WFO) PRK in patients with myopia. Eight randomized clinical trials were included. We searched PubMed, Scopus, Web of Science and CENTRAL at March 2020, and updated the search in September 2020 using relevant keywords, The data were extracted and pooled as Mean Difference (MD) with a 95% Confidence Interval (CI), using Review Manager software (version 5.4). Pooled results showed no significance between Uncorrected Distance Visual Acuity (UDVA) and Corrected Distance Visual Acuity (CDVA) between both groups underwent WFG and WFO PPR after three months follow up (MD = -0.03; 95% CI: [-0.06, 0.00]; P = 0.07), (MD = -0.02; 95% CI: [-0.04, 0.01]; P = 0.22) respectively. Although, no significant difference between mean manifest cylinder after three and 12 months follow up, but the total MD for mean manifest cylinder difference was significantly lower with the WFG treatment method (MD = -0.12, (95% CI: [0.23:-0.01], P = 0.03). This shows a slight advantage of the WFG over the WFO method. The visual performance showed similarity and excellent refractive outcomes in both WFO and WFG PRK. No significant statistical differences between the two approaches. On further comparison, there was a slight advantage of the WFG over the WFO method.
Topics: Corneal Wavefront Aberration; Humans; Lasers, Excimer; Photorefractive Keratectomy; Prospective Studies; Refraction, Ocular; Treatment Outcome
PubMed: 33229644
DOI: 10.4103/ijo.IJO_2921_20 -
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 -
Translational Vision Science &... May 2019To evaluate the efficacy of the functional, keratometric, and refractive postoperative parameters of intracorneal ring segment (ICRS) implantation in keratoconus and its... (Review)
Review
PURPOSE
To evaluate the efficacy of the functional, keratometric, and refractive postoperative parameters of intracorneal ring segment (ICRS) implantation in keratoconus and its association with collagen cross-linking (CXL), photorefractive keratectomy (PRK), and intraocular lenses (IOLs).
METHODS
We conducted a systematic review and meta-analysis on case series published between 2007 and 2017.
RESULTS
We included 95 case series with a total of 4560 patients. We included 64 studies of the ICRS procedure, 20 studies of ICRS+CXL, 9 studies of ICRS+CXL+PRK, and 5 studies of ICRS+IOL. We demonstrated an overall improvement of all parameters in all procedures. Cylinder was decreased with an overall effect size (ES) of -1.15 (-1.36 to -0.95; I = 93.7%). Corrected distance visual acuity was improved with an overall ES of 0.89 (0.78 to 1.00; I = 81.9%). Maximal keratometry was decreased with an overall ES of 0.98 (0.85 to 1.11; I = 78.9%). ICRS+IOL is the best procedure to improve spherical equivalent and uncorrected distance visual acuity ( < 0.05) compared with other procedures. ICRSs versus ICRS+CXL are similar in all parameters except for corrected distance visual acuity. ICRS+CXL+PRK is better than ICRS alone in all parameters except for the correction of spherical equivalent.
CONCLUSIONS
Although the quality and strength of the data are questionable, ICRS implantation is an effective strategy to preserve visual function in keratoconic patients. Particularly, ICRS+CXL+PRK could be a low invasive procedure to propose to young keratoconic patients.
TRANSLATIONAL RELEVANCE
To propose an overview of postoperative parameters on each ICRS procedure on keratoconus.
PubMed: 31211003
DOI: 10.1167/tvst.8.3.38 -
Pain Physician Jul 2017Refractive surgery is a common procedure, but may be associated with severe post-operative pain. (Review)
Review
BACKGROUND
Refractive surgery is a common procedure, but may be associated with severe post-operative pain.
OBJECTIVES
To describe studies addressing the use of opioids for control of pain after ocular surgery, with an emphasis on refractive surgery.
STUDY DESIGN
This is a narrative review of relevant articles on the physiology of corneal pain and the use of opioids for its treatment after surgery.
SETTING
Single tertiary center.
METHODS
A PubMed search was conducted for studies published from January 1985 to May 2015 on the physiopathology of corneal pain and opioid treatment of post-refractive surgical pain. Reviews, meta-analyses, and randomized clinical trials were included. Inclusion criteria focused on photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).
RESULTS
Authors found 109 articles through the search strategies. A total of 75 articles were included based on the inclusion criteria.
DISCUSSION
Pain after ocular surgery is likely to be a multifactorial phenomenon. A combination of topical and systemic analgesics is used to treat post-operative pain after refractive surgery. Pain may be severe during the first 72 to 96 hours, depending on the surgical procedure. No studies were found that directly analyze the benefits of opioids after PRK, although they are routinely prescribed in some centers.
LIMITATIONS
This is a narrative review in contrast to a systematic review and did not include studies indexed in databases other than PubMed.
CONCLUSIONS
Although opioids are used for the short-term treatment of post-operative pain in refractive surgery, their benefits and risks should be properly evaluated in randomized clinical trials before their use can be safely advised.
KEY WORDS
Photorefractive keratectomy, in situ keratomileusis, pain, analgesia, opioid, codeine, review.
Topics: Analgesics, Opioid; Humans; Ophthalmologic Surgical Procedures; Pain, Postoperative
PubMed: 28727706
DOI: No ID Found -
American Journal of Ophthalmology Jun 2017To compare the postoperative efficacy, predictability, safety, and visual quality of all major forms of laser corneal refractive surgeries for correcting myopia. (Meta-Analysis)
Meta-Analysis Review
PURPOSE
To compare the postoperative efficacy, predictability, safety, and visual quality of all major forms of laser corneal refractive surgeries for correcting myopia.
DESIGN
Systematic review and network meta-analysis.
METHODS
Search of MEDLINE, EMBASE, Cochrane Library, and the US trial registry was conducted up to November 2015. Randomized controlled trials (RCT) reporting in accordance with the eligibility criteria were included in this review. We performed a Bayesian random-effects network meta-analysis.
RESULTS
Forty-eight RCTs were identified. For efficacy (uncorrected visual acuity [UCVA]), there were no statistically significant differences between any pair of treatments analyzed. The SUCRA (surface under the cumulative ranking curve) ranking (from best to worst) was femtosecond-based laser in situ keratomileusis (FS-LASIK), LASIK, small-incision lenticule extraction, femtosecond lenticule extraction (FLEx), photorefractive keratectomy (PRK), laser epithelial keratomileusis (LASEK), epipolis (Epi)-LASIK, transepithelial PRK (T-PRK). For predictability (refractive spherical equivalent [SE]), a statistically significant difference was found when FS-LASIK was compared with LASIK (odds ratio [OR] 2.29, 95% credible interval [CrI] 1.20-4.14), PRK (OR 2.16, 95% CrI 1.15-4.03), LASEK (OR 2.09, 95% CrI 1.08-4.55), and Epi-LASIK (OR 2.74, 95% CrI 1.11-6.20). The SUCRA ranking (from best to worst) was FS-LASIK, T-PRK, LASEK, PRK, LASIK, Epi-LASIK. There were no statistically significant differences in the safety (best spectacle-corrected visual acuity) comparisons. For both postoperative higher-order aberrations (HOAs) and contrast sensitivity (CS), there were no statistically significant differences between any pair of treatments analyzed. The SUCRA ranking results show that some corneal surface ablation techniques (PRK and LASEK) rank highest.
CONCLUSIONS
This network meta-analysis shows that there were no statistically significant differences in either visual outcomes (efficacy and safety) or visual quality (HOAs and CS). FS-LASIK behaved better in predictability than any other type of surgeries.
Topics: Cornea; Humans; Lasers, Excimer; Myopia; Network Meta-Analysis; Photorefractive Keratectomy; Postoperative Period; Refraction, Ocular; Visual Acuity
PubMed: 28336402
DOI: 10.1016/j.ajo.2017.03.013 -
The Cochrane Database of Systematic... Feb 2017Near-sightedness, or myopia, is a condition in which light rays entering the eye along the visual axis focus in front of the retina, resulting in blurred vision. Myopia... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Near-sightedness, or myopia, is a condition in which light rays entering the eye along the visual axis focus in front of the retina, resulting in blurred vision. Myopia can be treated with spectacles, contact lenses, or refractive surgery. Options for refractive surgery include laser-assisted subepithelial keratectomy (LASEK) and laser-assisted in-situ keratomileusis (LASIK). Both procedures utilize a laser to shape the corneal tissue (front of the eye) to correct refractive error, and both create flaps before laser treatment of corneal stromal tissue. Whereas the flap in LASEK is more superficial and epithelial, in LASIK it is thicker and also includes some anterior stromal tissue. LASEK is considered a surface ablation procedure, much like its predecessor, photorefractive keratectomy (PRK). LASEK was developed as an alternative to PRK to address the issue of pain associated with epithelial debridement used for PRK. Assessing the relative benefits and risks/side effects of LASEK and LASIK warrants a systematic review.
OBJECTIVES
To assess the effects of LASEK versus LASIK for correcting myopia.
SEARCH METHODS
We searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Eyes and Vision Trials Register (2016, Issue 10); MEDLINE Ovid (1946 to 24 October 2016); Embase.com (1947 to 24 October 2016); PubMed (1948 to 24 October 2016); LILACS (Latin American and Caribbean Health Sciences Literature Database; 1982 to 24 October 2016); the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), last searched 20 June 2014; ClinicalTrials.gov (www.clinicaltrials.gov); searched 24 October 2016; and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 24 October 2016. We did not use any date or language restrictions in the electronic searches for trials.
SELECTION CRITERIA
We considered only randomized controlled trials (RCTs) for the purposes of this review. Eligible RCTs were those in which myopic participants were assigned randomly to receive either LASEK or LASIK in one or both eyes. We also included paired-eye studies in which investigators randomly selected which of the participant's eyes would receive LASEK or LASIK and assigned the other eye to the other procedure. Participants were men or women between the ages of 18 and 60 years with myopia up to 12 diopters (D) and/or myopic astigmatism of severity up to 3 D, who did not have a history of prior refractive surgery.
DATA COLLECTION AND ANALYSIS
Two review authors independently screened all reports and assessed the risk of bias in trials included in this review. We extracted data and summarized findings using risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes. In the absence of clinical and methodological heterogeneity across trials, we used a random-effects model to calculate summary effect estimates. We used a fixed-effect model when including fewer than three trials in a meta-analysis. When clinical, methodological, or statistical heterogeneity was observed across trials, we reported our findings in a narrative synthesis.
MAIN RESULTS
We identified four eligible trials with 538 eyes of 392 participants for the review, but only three trials (154 participants) provided outcome data for analysis. We found no ongoing trials. Two of four trials were from China, one trial was from Turkey, and the location of one trial was not reported. The risk of bias for most domains was unclear due to poor reporting of trial methods; no trial had a protocol or trial registry record. Three trials enrolled participants with mild to moderate myopia (less than -6.50 D); one trial included only participants with severe myopia (more than -6.00 D).The evidence showed uncertainty in whether there is a difference between LASEK and LASIK in uncorrected visual acuity (UCVA) at 12 months, the primary outcome in our review. The RR and 95% confidence interval (CI) at 12 months after surgery was 0.96 (95% CI 0.82 to 1.13) for UCVA of 20/20 or better and 0.90 (95% CI 0.67 to 1.21) for UCVA of 20/40 or better based on data from one trial with 57 eyes (very low-certainty evidence). People receiving LASEK were less likely to achieve a refractive error within 0.5 diopters of the target at 12 months follow-up (RR 0.69, 95% CI 0.48 to 0.99; 57 eyes; very low-certainty evidence). One trial reported mild corneal haze at six months in one eye in the LASEK group and none in the LASIK group (RR 2.11, 95% CI 0.57 to 7.82; 76 eyes; very low-certainty evidence). None of the included trials reported postoperative pain score or loss of visual acuity, spherical equivalent of the refractive error, or quality of life at 12 months.Refractive regression, an adverse event, was reported only in the LASEK group (8 of 37 eyes) compared with none of 39 eyes in the LASIK group in one trial (low-certainty evidence). Other adverse events, such as corneal flap striae and refractive over-correction, were reported only in the LASIK group (5 of 39 eyes) compared with none of 37 eyes in the LASEK group in one trial (low-certainty evidence).
AUTHORS' CONCLUSIONS
Overall, from the available RCTs, there is uncertainty in how LASEK compares with LASIK in achieving better refractive and visual results in mildly to moderately myopic participants. Large, well-designed RCTs would be required to estimate the magnitude of any difference in efficacy or adverse effects between LASEK and LASIK for treating myopia or myopic astigmatism.
Topics: Adult; Female; Humans; Keratectomy, Subepithelial, Laser-Assisted; Keratomileusis, Laser In Situ; Male; Middle Aged; Myopia; Quality of Life; Randomized Controlled Trials as Topic; Visual Acuity
PubMed: 28197998
DOI: 10.1002/14651858.CD011080.pub2 -
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 -
The Cochrane Database of Systematic... Jun 2012Hyperopia, or hypermetropia (also known as long-sightedness or far-sightedness), is the condition where the unaccommodating eye brings parallel light to a focus behind... (Comparative Study)
Comparative Study Review
BACKGROUND
Hyperopia, or hypermetropia (also known as long-sightedness or far-sightedness), is the condition where the unaccommodating eye brings parallel light to a focus behind the retina instead of on it. Hyperopia can be corrected with both non-surgical and surgical methods, among them photorefractive keratectomy (PRK) and laser assisted In situ keratomileusis (LASIK). There is uncertainty as to whether hyperopic-PRK or hyperopic-LASIK is the better method.
OBJECTIVES
The objectives of this review were to determine whether PRK or LASIK leads to more reliable, stable and safe results when correcting a hyperopic refractive error.
SEARCH METHODS
We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 2), MEDLINE (January 1950 to February 2012), EMBASE (January 1980 to February 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to February 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 17 February 2012. When trials are included in the review we will search the reference lists of the studies included in the review for information about further trials. We will use the Science Citation Index to search for papers that cite any studies included in this review. We did not handsearch journals or conference proceedings specifically for this review.
SELECTION CRITERIA
We planned to include only randomised controlled trials (RCTs) comparing PRK against LASIK for correction of hyperopia and then perform a sensitivity analysis of pre- and post-millennial trials since this is the mid-point in the history of both PRK and LASIK.
DATA COLLECTION AND ANALYSIS
We did not identify any studies that met the inclusion criteria for this review.
MAIN RESULTS
As no studies met the inclusion criteria for this review, we discussed the results of non-randomised trials comparing hyperopic-PRK with hyperopic-LASIK.
AUTHORS' CONCLUSIONS
No robust, reliable conclusions could be reached, but the non-randomised trials reviewed appear to be in agreement that hyperopic-PRK and hyperopic-LASIK are of comparable efficacy. High quality, well-planned open RCTs are needed in order to obtain a robust clinical evidence base.
Topics: Humans; Hyperopia; Keratomileusis, Laser In Situ; Photorefractive Keratectomy
PubMed: 22696365
DOI: 10.1002/14651858.CD007112.pub3