An in vitro assessment of the thermoreversible PLGA-PEG-PLGA copolymer: Implications for Descemet's membrane endothelial keratoplasty.

BACKGROUND: To explore the use of a thermoreversible copolymer gel coating to prevent donor tissue scrolling in Descemet's membrane endothelial keratoplasty (DMEK). METHODS: PLGA-PEG-PLGA triblock copolymer was synthesised via ring opening polymerisation. Two formulations were fabricated and gelation properties characterised using rheological analyses. Endothelial cytotoxicity of the copolymer was assessed using a Trypan Blue exclusion assay. Thickness of the copolymer gel coating on the endothelial surface was analysed using anterior segment optical coherence tomography (OCT) (RTVue-100, Optovue Inc.). Gold nanoparticles were added to the copolymer to aid visualisation using OCT. Prevention of Descemet membrane donor scrolling was represented via a novel, in vitro, immersion of copolymer coated donor graft material. RESULTS: Two different formulations of PLGA-PEG-PLGA copolymer were successfully fabricated and the desired peak gelling temperature of 24°C was achieved by polymer blending. Application of 20%, 30% and 40% (wt/vol) polymer concentrations resulted in a statistically significant increase in polymer thickness on the endothelium (p < 0.001). There was no detectable endothelial cytotoxicity. The polymer was easy to apply to the endothelium and prevented scrolling of the DMEK graft. CONCLUSION: This PLGA-PEG-PLGA thermoreversible copolymer gel could be exploited as a therapeutic aid for preventing DMEK graft scrolling.

Keratoconus Natural Progression: A Systematic Review and Meta-analysis of 11 529 Eyes.

PURPOSE: We set out to describe the natural history of keratoconus. We included untreated patients, and our key outcome measures were vision, refraction, and corneal curvature. CLINICAL RELEVANCE: Keratoconus affects 86 in 100 000 people, causing visual loss due to increasing irregular corneal astigmatism, and the quality of life declines in patients. Interventions are used to stabilize the disease or improve vision, including corneal cross-linking (CXL) and grafting, but these carry risks. Detailed knowledge of the natural history of keratoconus is fundamental in making informed decisions on when their benefits outweigh these risks. METHODS: We included prospective or retrospective studies of pediatric or adult patients who reported 1 or more of visual acuity, refraction, and corneal curvature measures: steep keratometry (K2), mean keratometry (Kmean), or maximum keratometry (Kmax), thinnest pachymetry, corneal transplantation rates, corneal scarring incidence, and patient-reported outcome measures (PROMs). Databases analyzed included Medline, Embase, CENTRAL, and CINAHL. Searches were carried out until October 2018. Bias assessment was carried out using the Joanna Briggs Institute model of evidence-based healthcare. RESULTS: Our search yielded 3950 publication titles, of which 41 were included in our systematic review and 23 were incorporated into the meta-analysis. Younger patients and those with greater Kmax demonstrated more steepening of Kmax at 12 months. The meta-analysis for Kmax demonstrated a significant increase in Kmax of 0.7 diopters (D) at 12 months (95% confidence interval [CI], 0.31-1.14; P = 0.003). Our meta-regression model predicted that patients had 0.8 D less Kmax steepening over 12 months for every 10-year increase in age (P = 0.01). Patients were predicted to have 1 D greater Kmax steepening for every 5 D of greater baseline Kmax (P = 0.003). At 12 months, there was a significant increase in the average Kmean of 0.4 D (95% CI, 0.18-0.65; P = 0.004). CONCLUSIONS: We report the first systematic review and meta-analysis of keratoconus natural history data including 11 529 eyes. Younger patients and those with Kmax steeper than 55 D at presentation have a significantly greater risk of progression of keratoconus. Closer follow-up and a lower threshold for cross-linking should be adopted in patients younger than 17 years and steeper than 55 D Kmax.

Quality of vision after bilateral multifocal intraocular lens implantation: a randomized trial--AT LISA 809M versus AcrySof ReSTOR SN6AD1.

PURPOSE: To compare postoperative visual symptoms and spectacle freedom after bilateral implantation of the AT LISA 809M (Carl Zeiss Meditec, Jena, Germany) versus the AcrySof ReSTOR SN6AD1 (Alcon Laboratories, Irvine, CA) multifocal intraocular lens (IOL). DESIGN: Double-masked, prospective, randomized, controlled clinical trial. PARTICIPANTS: A total of 188 patients undergoing bilateral sequential cataract surgery or bilateral refractive lens exchange. METHODS: Patients were preoperatively randomized (allocation ratio 1:1) to bilateral implantation with the AT LISA 809M IOL or ReSTOR SN6AD1 IOL. Postoperative outcomes were assessed 4 to 8 months after second eye surgery. MAIN OUTCOME MEASURES: The primary outcome was visual symptoms evaluated with the Quality of Vision (QoV) questionnaire. Secondary outcomes included other questionnaire data (CatQuest-9SF, spectacle independence, vision satisfaction, and dysphotopsia) and visual function measures (near, intermediate, and distance visual acuity, binocular reading speed [International Reading Speed Texts], contrast sensitivity, and forward light scatter). Adverse events, including intraoperative and postoperative complications, also were evaluated. RESULTS: There was no significant difference between IOL groups in Rasch-adjusted QoV scores for frequency (P = 0.95), severity (P = 0.56), and bothersomeness (P = 0.34) of visual symptoms; median (interquartile) scores for these QoV subscales were 29 (15-37), 22 (13-27), and 14 (0-29) for the AT LISA 809M IOL group, respectively, and 32 (15-37), 22 (13-30), and 14 (0-29) for the ReSTOR SN6AD1 IOL group, respectively. Halo was the most prominent dysphotopsia symptom, with 6% in both IOL groups reporting halo symptoms as very bothersome. Complete spectacle independence was achieved in 69 of 84 (82.1%) AT LISA 809M recipients and 66 of 85 (77.6%) ReSTOR SN6AD1 recipients (P = 0.57). Preferred reading distance was slightly nearer for the AT LISA 809M IOL. There were no statistically significant differences in any of the other secondary outcome measures. CONCLUSIONS: Visual symptoms were similar after bilateral implantation of the AT LISA 809M and ReSTOR SN6AD1 IOLs. Both these diffractive bifocal IOLs produce high levels of spectacle independence and patient satisfaction. However, a small but clinically significant minority of patients remained symptomatic and dissatisfied with visual results 4 to 8 months after surgery.

Excimer laser refractive surgery versus phakic intraocular lenses for the correction of moderate to high myopia.

BACKGROUND: Myopia is a condition in which the focusing power (refraction) of the eye is greater than that required for clear distance vision. There are two main types of surgical correction for moderate to high myopia; excimer laser and phakic intraocular lenses (IOLs). Excimer laser refractive surgery for myopia works by removing corneal stroma to lessen the refractive power of the cornea and to bring the image of a viewed object into focus onto the retina rather than in front of it. Phakic IOLs for the treatment of myopia work by diverging light rays so that the image of a viewed object is brought into focus onto the retina rather than in front of the retina. They can be placed either in the anterior chamber of the eye in front of the iris or in the posterior chamber of the eye between the iris and the natural lens. OBJECTIVES: To compare excimer laser refractive surgery and phakic IOLs for the correction of moderate to high myopia by evaluating postoperative uncorrected visual acuity, refractive outcome, potential loss of best spectacle corrected visual acuity (BSCVA) and the incidence of adverse outcomes. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to February 2014), EMBASE (January 1980 to February 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), 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 11 February 2014. SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing excimer laser refractive surgery and phakic IOLs for the correction of myopia greater than 6.0 diopters (D) spherical equivalent. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted data. We performed data analysis. We summarised data for outcomes using odds ratios. We used a fixed-effect model as only three trials were included in the review. MAIN RESULTS: This review included three RCTs with a total of 228 eyes. The range of myopia of included patients was -6.0 D to -20.0 D of myopia with up to 4.0 D of myopic astigmatism. The percentage of eyes with uncorrected visual acuity (UCVA) of 20/20 or better at 12 months postoperative was not significantly different between the two groups. Phakic IOL surgery was safer than excimer laser surgical correction for moderate to high myopia as it results in significantly less loss of best spectacle corrected visual acuity (BSCVA) at 12 months postoperatively. However there is a low risk of developing early cataract with phakic IOLs. Phakic IOL surgery appears to result in better contrast sensitivity than excimer laser correction for moderate to high myopia. Phakic IOL surgery also scored more highly on patient satisfaction/preference questionnaires. AUTHORS' CONCLUSIONS: The results of this review suggest that, at one year post surgery, phakic IOLs are safer than excimer laser surgical correction for moderate to high myopia in the range of -6.0 to -20.0 D and phakic IOLs are preferred by patients. While phakic IOLs might be accepted clinical practice for higher levels of myopia (greater than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism), it may be worth considering phakic IOL treatment over excimer laser correction for more moderate levels of myopia (less than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism). Further RCTs adequately powered for subgroup analysis are necessary to further elucidate the ideal range of myopia for phakic IOLs. This data should be considered alongside comparative data addressing long-term safety as it emerges.

Accommodative intraocular lens versus standard monofocal intraocular lens implantation in cataract surgery.

BACKGROUND: Following cataract surgery and intraocular lens (IOL) implantation, loss of accommodation or postoperative presbyopia occurs and remains a challenge. Standard monofocal IOLs correct only distance vision; patients require spectacles for near vision. Accommodative IOLs have been designed to overcome loss of accommodation after cataract surgery. OBJECTIVES: To define (a) the extent to which accommodative IOLs improve unaided near visual function, in comparison with monofocal IOLs; (b) the extent of compromise to unaided distance visual acuity; c) whether a higher rate of additional complications is associated the use of accommodative IOLs. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 9), Ovid MEDLINE, Ovid MEDLINE in-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily Update, Ovid OLDMEDLINE (January 1946 to October 2013), EMBASE (January 1980 to October 2013), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to October 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrial.gov) and the 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 10 October 2013. SELECTION CRITERIA: We include randomised controlled trials (RCTs) which compared implantation of accommodative IOLs to implantation of monofocal IOLs in cataract surgery. DATA COLLECTION AND ANALYSIS: Two authors independently screened search results, assessed risk of bias and extracted data. All included trials used the 1CU accommodative IOL (HumanOptics, Erlangen, Germany) for their intervention group. One trial had an additional arm with the AT-45 Crystalens accommodative IOL (Eyeonics Vision). We performed a separate analysis comparing 1CU and AT-45 IOL. MAIN RESULTS: We included four RCTs, including 229 participants (256 eyes), conducted in Germany, Italy and the UK. The age range of participants was 21 to 87 years. All studies included people who had bilateral cataracts with no pre-existing ocular pathologies. We judged all studies to be at high risk of performance bias. We graded two studies with high risk of detection bias and one study with high risk of selection bias.Participants who received the accommodative IOLs achieved better distance-corrected near visual acuity (DCNVA) at six months (mean difference (MD) -3.10 Jaeger units; 95% confidence intervals (CI) -3.36 to -2.83, 2 studies, 106 people, 136 eyes, moderate quality evidence). Better DCNVA was seen in the accommodative lens group at 12 to 18 months in the three trials that reported this time point but considerable heterogeneity of effect was seen, ranging from 1.3 (95% CI 0.98 to 1.68; 20 people, 40 eyes) to 6 (95% CI 4.15 to 7.85; 51 people, 51 eyes) Jaeger units and 0.12 (95% CI 0.05 to 0.19; 40 people, binocular) logMAR improvement (low quality evidence). The relative effect of the lenses on corrected distant visual acuity (CDVA) was less certain. At six months there was a standardised mean difference of -0.04 standard deviations (95% CI -0.37 to 0.30, 2 studies, 106 people, 136 eyes, low quality evidence). At long-term follow-up there was heterogeneity of effect with 18-month data in two studies showing that CDVA was better in the monofocal group (MD 0.12 logMAR; 95% CI 0.07 to 0.16, 2 studies, 70 people,100 eyes) and one study which reported data at 12 months finding similar CDVA in the two groups (-0.02 logMAR units, 95% CI -0.06 to 0.02, 51 people) (low quality evidence).The relative effect of the lenses on reading speed and spectacle independence was uncertain, The average reading speed was 11.6 words per minute more in the accommodative lens group but the 95% confidence intervals ranged from 12.2 words less to 35.4 words more (1 study, 40 people, low quality evidence). People with accommodative lenses were more likely to be spectacle-independent but the estimate was very uncertain (risk ratio (RR) 8.18; 95% CI 0.47 to 142.62, 1 study, 40 people, very low quality evidence).More cases of posterior capsule opacification (PCO) were seen in accommodative lenses but the effect of the lenses on PCO was uncertain (Peto odds ratio (OR) 2.12; 95% CI 0.45 to 10.02, 91 people, 2 studies, low quality evidence). People in the accommodative lens group were more likely to require laser capsulotomy (Peto OR 7.96; 95% CI 2.49 to 25.45, 2 studies, 60 people, 80 eyes, low quality evidence). Glare was reported less frequently with accommodative lenses but the relative effect of the lenses on glare was uncertain (RR any glare 0.78; 95% CI 0.32 to 1.90, 1 study, 40 people, and RR moderate/severe glare 0.45; 95% CI 0.04 to 4.60, low quality evidence). AUTHORS' CONCLUSIONS: There is moderate-quality evidence that study participants who received accommodative IOLs had a small gain in near visual acuity after six months. There is some evidence that distance visual acuity with accommodative lenses may be worse after 12 months but due to low quality of evidence and heterogeneity of effect, the evidence for this is not clear-cut. People receiving accommodative lenses had more PCO which may be associated with poorer distance vision. However, the effect of the lenses on PCO was uncertain.Further research is required to improve the understanding of how accommodative IOLs may affect near visual function, and whether they provide any durable gains. Additional trials, with longer follow-up, comparing different accommodative IOLs, multifocal IOLs and monofocal IOLs, would help map out their relative efficacy, and associated late complications. Research is needed on control over capsular fibrosis postimplantation.Risks of bias, heterogeneity of outcome measures and study designs used, and the dominance of one design of accommodative lens in existing trials (the HumanOptics 1CU) mean that these results should be interpreted with caution. They may not be applicable to other accommodative IOL designs.

A comparison of keratoconus progression following collagen cross-linkage using standard or personalised keratometry thresholds.

OBJECTIVE: To define how estimates of keratoconus progression following collagen cross-linking (CXL) vary according to the parameter selected to measure corneal shape. MATERIALS AND METHODS: We estimated progression following CXL in 1677 eyes. We compared standard definitions of keratoconus progression based on published thresholds for Kmax, front K2, or back K2, or progression of any two of these three parameters, with the option of an increased threshold for Kmax values ≥ 55D. As corneal thickness reduces unpredictably after CXL, it was excluded from the principal analysis. We then repeated the analysis using novel adaptive estimates of progression for Kmax, front K2, or back K2, developed separately using 6463 paired readings from keratoconus eyes, with a variation of the Bland-Altman method to determine the 95% regression-based limits of agreement (LoA). We created Kaplan-Meier survival plots for both standard and adaptive thresholds. The primary outcome was progression five years after a baseline visit 9-15 months following CXL. RESULTS: Progression rates were 8% with a standard (≥ 1.5D) threshold for K2 or 6% with the static multi-parameter definition. With a ≥ 1D threshold for Kmax, the progression was significantly higher at 29%. With adaptive Kmax or K2, the progression rates were similar (20%) but less than with the adaptive multi-parameter method (22%). CONCLUSIONS: Estimates of keratoconus progression following CXL vary widely according to the reference criteria. Using adaptive thresholds (LoA) to define the repeatability of keratometry gives estimates for progression that are markedly higher than with the standard multi-parameter method.

Suboptimal visual outcome after femto-LASIK ablation in a high myopic patient.

A 28-year-old nurse had an aberration-free femto-laser in situ keratomileusis (LASIK) performed for her myopia of -6.25 -0.50 × 096 and -6.75 -0.50 × 175 in the right and left eye, respectively. Corrected distance visual acuity (CDVA) preoperatively was 20/16. Preoperatively, there were no abnormalities on Scheimpflug imaging, and a pachymetry of 585 µm was measured in both eyes. Flap thickness was 115 µm. The patient was quite nervous during the surgery. Since the surgery, her uncorrected distance visual acuity (UDVA) and CDVA are suboptimal at 20/30 and 20/20 in the right eye, and 20/20 and 20/16 in the left eye. 3 months postoperatively, there is a stable manifest refraction of +0.25 -1.25 × 030 and +0.25 -0.00 × 0. The keratometric astigmatism in the Scheimpflug imaging is 1.2 diopter (D) × 114 and 0.4 D × 78 in the right and left eyes, respectively (FIgures 1 and 2). Thinnest pachymetry is 505 µm and 464 µm in the right and left eye, respectively. Her wavefront analysis shows refraction in a 6 mm zone of -0.99 -1.22 × 32 and -0.91 -0.36 × 136. The cycloplegic refraction is 1.25 -1.00 × 023 and +1.00 -0.25 × 006 (Figures 3 and 4). What is the cause of the suboptimal visual outcome in this case? What would be your treatment strategy to improve visual outcome?

Randomized trial of multifocal intraocular lenses versus monovision after bilateral cataract surgery.

OBJECTIVE: To compare spectacle independence in patients randomized to receive bilateral multifocal intraocular lenses (IOLs) or monofocal IOLs with the powers adjusted to produce monovision. DESIGN: Randomized, multicenter clinical trial. PARTICIPANTS: A total of 212 patients with bilateral, visually significant cataract. METHODS: Before bilateral sequential cataract surgery, patients were randomized (allocation ratio 1:1) to receive bilateral Tecnis ZM900 diffractive multifocal lenses (Abbott Medical Optics, Santa Ana, CA) or Akreos AO monofocal lenses (Bausch & Lomb, Rochester, NY) with the powers adjusted to target -1.25 diopters (D) monovision. Outcomes were assessed 4 months after the second eye underwent operation. MAIN OUTCOME MEASURES: The primary outcome was spectacle independence. Secondary outcomes included questionnaires (VF-11R, dysphotopsia symptoms, and satisfaction) and visual function measures (near, intermediate, and distance logarithm of minimum angle of resolution [logMAR] visual acuity, stereoacuity, contrast sensitivity, and forward light scatter). RESULTS: A total of 212 patients were randomized, and 187 patients (88%) returned for assessment 4 months after surgery. Uniocular distance refractions in the monovision arm showed a mean spherical equivalent of +0.075 D in the distance eye and -0.923 in the near eye. In the multifocal arm, the mean distance spherical equivalents were -0.279 D and -0.174 D in the right and left eyes, respectively. A total of 24 of 93 patients (25.8%) in the monovision arm and 67 of 94 patients (71.3%) in the multifocal arm reported never wearing glasses (P<0.001, Fisher exact test). The adjusted odds ratio of being spectacle free was 7.51 (95% confidence interval, 3.89-14.47). Binocular uncorrected acuities did not differ significantly for distance (0.058 logMAR for monovision vs. 0.076 for multifocal, P = 0.3774) but were significantly worse in the multifocal arm for intermediate acuity (0.149 vs. 0.221, P = 0.0001) and in the monovision arm for near acuity (0.013 vs. -0.025, P = 0.037). In the first postoperative year, 6 patients (5.7%) in the multifocal arm underwent IOL exchange (4 had a bilateral and 2 had a unilateral exchange). No patients in the monovision arm underwent IOL exchange. CONCLUSIONS: Patients randomized to bilateral implantation with the diffractive multifocal Tecnis ZM900 were more likely to report being spectacle independent but also more likely to undergo IOL exchange than those randomized to receive monofocal implants (Akreos AO) with the powers adjusted to give low monovision.

Laser-assisted in-situ keratomileusis (LASIK) versus photorefractive keratectomy (PRK) for myopia.

BACKGROUND: Myopia (also known as short-sightedness or near-sightedness) is an ocular condition in which the refractive power of the eye is greater than is required, resulting in light from distant objects being focused in front of the retina instead of directly on it. The two most commonly used surgical techniques to permanently correct myopia are photorefractive keratectomy (PRK) and laser-assisted in-situ keratomileusis (LASIK). OBJECTIVES: To compare the effectiveness and safety of LASIK and PRK for correction of myopia by examining post-treatment uncorrected visual acuity, refractive outcome, loss of best spectacle-corrected visual acuity, pain scores, flap complications in LASIK, subepithelial haze, adverse events, quality of life indices and higher order aberrations. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 11), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to November 2012), EMBASE (January 1980 to November 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to November 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). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 15 November 2012. We also searched the reference lists of the studies and the Science Citation Index. SELECTION CRITERIA: We included randomised controlled trials comparing LASIK and PRK for the correction of any degree of myopia. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted data. We summarised data using the odds ratio and mean difference. We combined odds ratios using a random-effects model after testing for heterogeneity. MAIN RESULTS: We included 13 trials (1135 participants, 1923 eyes) in this review. Nine of these trials randomised eyes to treatment, two trials randomised people to treatment and treated both eyes, and two trials randomised people to treatment and treated one eye. None of the paired trials reported an appropriate paired analysis. We considered the overall quality of evidence to be low for most outcomes because of the risk of bias in the included trials. There was evidence that LASIK gives a faster visual recovery than PRK and is a less painful technique. Results at one year after surgery were comparable: most analyses favoured LASIK but they were not statistically significant. AUTHORS' CONCLUSIONS: LASIK gives a faster visual recovery and is a less painful technique than PRK. The two techniques appear to give similar outcomes one year after surgery. Further trials using contemporary techniques are required to determine whether LASIK and PRK as currently practised are equally safe. Randomising eyes to treatment is an efficient design, but only if analysed properly. In future trials, more efforts could be made to mask the assessment of outcome.

Excimer laser refractive surgery versus phakic intraocular lenses for the correction of moderate to high myopia.

BACKGROUND: Myopia is a condition in which the focusing power (refraction) of the eye is greater than that required for clear distance vision. There are two main types of surgical correction for moderate to high myopia; excimer laser and phakic intraocular lenses (IOLs). Excimer laser refractive surgery for myopia works by removing corneal stroma to lessen the refractive power of the cornea and to bring the image of a viewed object into focus onto the retina rather than in front of it. Phakic IOLs for the treatment of myopia work by diverging light rays so that the image of a viewed object is brought into focus onto the retina rather than in front of the retina. They can be placed either in the anterior chamber of the eye in front of the iris or in the posterior chamber of the eye between the iris and the natural lens. OBJECTIVES: The aim of this review is to compare the effect of excimer laser refractive surgery versus phakic IOLs for the correction of moderate to high myopia. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 11), MEDLINE (January 1950 to November 2011), EMBASE (January 1980 to November 2011), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to November 2011), 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 28 November 2011. SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing excimer laser refractive surgery and phakic IOLs for the correction of myopia greater than 6.0 diopters (D) spherical equivalent. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted data. We performed data analysis. We summarised data for outcomes using odds ratios. We used a fixed-effect model as only three trials were included in the review. MAIN RESULTS: This review included three RCTs with a total of 228 eyes. The range of myopia of included patients was -6.0 D to -20.0 D of myopia with up to 4.0 D of myopic astigmatism. The percentage of eyes with uncorrected visual acuity (UCVA) of 20/20 or better at 12 months postoperative was not significantly different between the two groups. Phakic IOL surgery was safer than excimer laser surgical correction for moderate to high myopia as it results in significantly less loss of best spectacle corrected visual acuity (BSCVA) at 12 months postoperatively. However there is a low risk of developing early cataract with phakic IOLs. Phakic IOL surgery appears to result in better contrast sensitivity than excimer laser correction for moderate to high myopia. Phakic IOL surgery also scored more highly on patient satisfaction/preference questionnaires. AUTHORS' CONCLUSIONS: The results of this review suggest that phakic IOLs are safer than excimer laser surgical correction for moderate to high myopia in the range of -6.0 to -20.0 D and phakic IOLs are preferred by patients. While phakic IOLs might be accepted clinical practice for higher levels of myopia (greater than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism), it may be worth considering phakic IOL treatment over excimer laser correction for more moderate levels of myopia (less than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism). Further RCTs adequately powered for subgroup analysis are necessary to further elucidate the ideal range of myopia for phakic IOLs.

The Vision Correction Questionnaire: an electronic patient-reported outcome measure for refractive surgery.

PURPOSE: To develop a psychometrically robust electronic patient reported outcome measure (ePROM) for refractive surgery. SETTING: Moorfields Eye Hospital, London, United Kingdom. DESIGN: Questionnaire development study. METHODS: Items were derived in 6 domains (spectacle dependence, visual quality, eye comfort, functional freedom, emotional wellbeing, and satisfaction with treatment) from existing Rasch adjusted instruments, patient and surgeon feedback, and refinement in semistructured interviews before administration to a field test cohort (n = 360) of patients undergoing routine refractive surgery. Spectacle dependence and satisfaction with treatment items were used to provide descriptive statistical information only. Contemporary criteria for item reduction and Rasch modeling were applied to the remaining domains. The finalized questionnaire was then administered to a second patient cohort (n = 120) before and after surgery to assess sensitivity to change. RESULTS: A 5-item scale derived for emotional wellbeing was unidimensional and a good fit to the Rasch model with ordered category response profiles, adequate precision (person separation 2.22 logits, reliability coefficient 0.83), and no misfitting items. Mean logit scores were 0.91 higher after treatment (effect size 1.26) suggesting a positive impact on emotional wellbeing. Functional scales could not be derived for visual quality, eye comfort, or functional freedom. Single-item ratings for visual quality and eye comfort were retained in our final 11-item questionnaire. CONCLUSIONS: This short ePROM should integrate well with routine clinical care and clinical trials in refractive surgery. The Rasch adjusted emotional wellbeing scale may help quantify the way patients feel about refractive surgery, with the remaining items providing useful descriptive information.

Safety-Net Suture for Aphakic Descemet Membrane Endothelial Keratoplasty.

PURPOSE: The purpose of this research was to describe a low-cost, accessible method for reducing the risk of posterior donor dislocation in Descemet membrane endothelial keratoplasty (DMEK) performed in eyes with aphakia and a large iris defect (unicameral eyes)-the "safety-net suture." METHODS: We review 3 cases of aphakic bullous keratopathy in unicameral eyes treated successfully using DMEK aided by a simple technique to create a temporary, partial barrier between the anterior and posterior chambers. The safety-net suture technique is based on a continuous 10-0 polypropylene suture placed across the anterior chamber in a cat's-cradle pattern anterior to the trabecular meshwork. At the end of surgery, after air tamponade of the DMEK donor, the 10-0 polypropylene suture is removed. RESULTS: All 3 cases were completed with no intraoperative posterior dislocation. A partial postoperative detachment in 1 case was successfully treated with repeat air tamponade. The corneas remain clear in early follow-up, 1 to 10 months after surgery. CONCLUSIONS: The safety-net suture is a simple, low-cost method of reducing the risk of intraoperative posterior dislocation for DMEK in unicameral, aphakic eyes.

Personalized Model to Predict Keratoconus Progression From Demographic, Topographic, and Genetic Data.

PURPOSE: To generate a prognostic model to predict keratoconus progression to corneal crosslinking (CXL). DESIGN: Retrospective cohort study. METHODS: We recruited 5025 patients (9341 eyes) with early keratoconus between January 2011 and November 2020. Genetic data from 926 patients were available. We investigated both keratometry or CXL as end points for progression and used the Royston-Parmar method on the proportional hazards scale to generate a prognostic model. We calculated hazard ratios (HRs) for each significant covariate, with explained variation and discrimination, and performed internal-external cross validation by geographic regions. RESULTS: After exclusions, model fitting comprised 8701 eyes, of which 3232 underwent CXL. For early keratoconus, CXL provided a more robust prognostic model than keratometric progression. The final model explained 33% of the variation in time to event: age HR (95% CI) 0.9 (0.90-0.91), maximum anterior keratometry 1.08 (1.07-1.09), and minimum corneal thickness 0.95 (0.93-0.96) as significant covariates. Single-nucleotide polymorphisms (SNPs) associated with keratoconus (n=28) did not significantly contribute to the model. The predicted time-to-event curves closely followed the observed curves during internal-external validation. Differences in discrimination between geographic regions was low, suggesting the model maintained its predictive ability. CONCLUSIONS: A prognostic model to predict keratoconus progression could aid patient empowerment, triage, and service provision. Age at presentation is the most significant predictor of progression risk. Candidate SNPs associated with keratoconus do not contribute to progression risk.

Accelerated Pulsed High-Fluence Corneal Cross-Linking for Progressive Keratoconus.

PURPOSE: To report on 2-year results of accelerated corneal collagen cross-linking (CXL) in progressive ectasia using the Avedro KXL system. DESIGN: Prospective interventional case series. METHODS: A total of 870 patients (1,192 eyes) attending Moorfields Eye Hospital after CXL were included. All patients undergoing CXL had progressive keratoconus. Corneas with a minimum stromal thickness <375 µm were excluded. Riboflavin 0.1% soak duration was 10 minutes. High-fluence pulsed UVA was delivered at 30 mW/cm2 for 4 minutes, with a 1.5-second on/off cycle (total energy 7.2 J/cm2). Subjective refractive, corneal tomography, and specular microscopy were performed at baseline, 6, 12, and 24 months postoperatively. The primary outcome measure was a change in maximum keratometry (Kmax) at 24 months. RESULTS: Twelve- and 24-month follow-up data were available on 543 and 213 patients, respectively (mean age 25.4 ± 6.6 years). In mild cones (Kmax < 55 diopter [D]), mean keratometry remained unchanged at 24 months. In more advanced disease, we observed modest corneal flattening compared to baseline (Kmax 63.2 ± 6.5 D vs 61.9 ± 8.1 D, P = .02), but no significant changes in central keratometry (K1 or K2). Keratometric stabilization was confirmed in 98.3% of eyes. Mean CDVA, manifest refraction and endothelial cell density did not change. Overall, 2.7% of eyes lost more than 2 lines of CDVA. CONCLUSION: Accelerated pulsed CXL is a safe, effective, and refractively neutral intervention (at 2 years) to halt disease progression in keratoconus.

Quality of life in high myopia before and after implantable Collamer lens implantation.

PURPOSE: To examine changes in vision-related quality of life after implantable Collamer lens (ICL) implantation for the correction of myopia. DESIGN: Prospective, interventional, consecutive case series. PARTICIPANTS: We included 34 consecutive patients (68% female; mean age, 37 years [range, 23-49]) with preoperative myopia (mean ± standard deviation [SD] refraction spherical equivalent, -11.0 ± 3.12). INTERVENTION: Bilateral ICL implantation. MAIN OUTCOME MEASURES: Quality of life Impact of Refractive Correction (QIRC) score. RESULTS: The median postoperative interval before questionnaire administration was 4 months (range, 3-7). The QIRC scores were significantly higher postoperatively (preoperative QIRC score [mean ± SD], 40.45 ± 4.83; postoperative QIRC score 53.79 ± 5.60; P < 0.001), with significant improvements (P<0.01) for 14 of 19 items. Nineteen (58%) patients reported a worsening in night vision symptoms (mostly nonspecific glare and halo or arc effects) after surgery, but overall levels of satisfaction were high; 88% were either satisfied or very satisfied with the results of surgery. No patients reported overall dissatisfaction. In free text responses, 11 patients (32%) described ICL implantation as life changing or wished that they had opted for the surgery sooner. CONCLUSIONS: Implantation of an ICL for myopia is associated with significant improvements in quality of life. Any dissatisfaction with the procedure largely relates to night vision symptoms, which are common in the early postoperative period.

Correcting post-keratoplasty anisometropia with the implantable collamer phakic intraocular lens.

BACKGROUND: We evaluate the Visian Implantable Collamer Lens (Staar, Monrovia, CA, USA) phakic intraocular lens for treating post-keratoplasty anisometropia. METHODS: Case series of three eyes (2 phakic and 1 pseudophakic). RESULTS: The mean age was 47.3 years (range 30-73 years), with a minimum of 3-month follow up. The mean preoperative spherical equivalent was -8.75 ± 5.17 D (-4.00 to -14.25 D) improving to -0.29 ± 1.21 D postoperatively (range 0.75 to -1.625 D). Mean logMAR uncorrected visual acuity improved from 1.66 ± 0.60 (6/240) preoperatively to 0.41 ± 0.52 (6/15(2) ). Mean logMAR best spectacle-corrected visual acuity improved from 0.32 ± 0.15 (6/12) preoperatively to 0.10 ± 0.11 (6/7.5). Anisometropia improved from a difference of 6.37 ± 2.59 D preoperatively to 2.09 ± 1.37 D postoperatively, and there were no complications. CONCLUSION: Our technique for this clinical indication shows that the Visian Implantable Collamer Lens is a safe and effective alternative for treating post-keratoplasty anisometropia.

Pyramidal Aberrometry in Wavefront-Guided Myopic LASIK.

PURPOSE: To evaluate measurement repeatability and clinical results for pyramidal aberrometry in routine myopic wavefront-guided laser in situ keratomileusis (LASIK). METHODS: Results from 265 consecutive eyes treated with myopic wavefront-guided LASIK using the Amaris 1050RS Excimer Laser and Peramis pyramidal aberrometer (SCHWIND eye-tech-solutions GmbH) were reviewed. Limits of repeatability were calculated for the aberrometric refraction spherical equivalent and higher order aberrations for the Peramis aberrometer using results from three consecutive scans acquired preoperatively and postoperatively for the first 100 eyes treated. RESULTS: The 95% limits of repeatability for pyramidal aberrometric measurement were: 0.3 diopters (D) for sphere, 0.2 D for cylinder, and 0.1 D (dioptric equivalent) for 3rd and 4th order aberration indices. A total of 95% of eyes were within ±0.50 D of the manifest refraction spherical equivalent target postoperatively. Uncorrected distance visual acuity was 20/20 or better in 96% of 232 eyes with a plano refraction target outcome. A total of 97% of eyes had a refraction cylinder of 0.50 D or less. No eyes lost one or more line of corrected distance visual acuity. CONCLUSIONS: These data demonstrate good measurement repeatability, safety, and efficacy for pyramidal aberrometry in routine myopic LASIK. [J Refract Surg. 2020;36(7):442-448.].

Femtosecond Laser-Assisted Deep Anterior Lamellar Keratoplasty for Keratoconus: Multi-surgeon Results.

PURPOSE: To compare the clinical outcomes in femtosecond laser-assisted deep anterior lamellar keratoplasty (F-DALK) to manual non-laser deep anterior lamellar keratoplasty (M-DALK) for keratoconus in a multi-surgeon public healthcare setting. DESIGN: Single-center, comparative, retrospective interventional case series. METHODS: Population: Consecutive cases of keratoconus treated with big-bubble F-DALK from August 1, 2015, to September 1, 2018 and big-bubble M-DALK from September 1, 2012, to September 30, 2016. SETTING: Moorfields Eye Hospital, London. OBSERVATIONS: Data on preoperative status, operative details, intraoperative and postoperative complications, secondary interventions, and visual outcomes were archived on a customized spreadsheet for analysis. MainOutcomeMeasures: Rate of intraoperative perforation and conversion to penetrating keratoplasty (PK) and the percentage of patients, post removal of sutures (ROS), with corrected distance visual acuity (CDVA) ≥20/40. RESULTS: We analyzed 58 eyes of 55 patients who underwent F-DALK and 326 eyes of 309 patients who underwent M-DALK. Intraoperative perforation of Descemet membrane occurred in 15 of 58 (25.9%) F-DALK cases compared to 148 of 326 (45.4%) M-DALK cases (P = .006). Intraoperative conversion to PK was carried out in 2 of 58 (3.4%) F-DALK cases compared to 80 of 326 (24.5%) M-DALK cases (P = .001). Post ROS, 86.5% of F-DALK eyes had a CDVA of ≥20/40 (15 ± 7.3 months after surgery) compared to 83.7% of M-DALK eyes (24.9 ± 10.6 months) (P = .825). CONCLUSION: Laser automation of some steps in DALK for keratoconus may reduce the rate of intraoperative Descemet perforation and the conversion to PK in a multi-surgeon setting.

LiQD Cornea: Pro-regeneration collagen mimetics as patches and alternatives to corneal transplantation.

Transplantation with donor corneas is the mainstay for treating corneal blindness, but a severe worldwide shortage necessitates the development of other treatment options. Corneal perforation from infection or inflammation is sealed with cyanoacrylate glue. However, the resulting cytotoxicity requires transplantation. LiQD Cornea is an alternative to conventional corneal transplantation and sealants. It is a cell-free, liquid hydrogel matrix for corneal regeneration, comprising short collagen-like peptides conjugated with polyethylene glycol and mixed with fibrinogen to promote adhesion within tissue defects. Gelation occurs spontaneously at body temperature within 5 min. Light exposure is not required-particularly advantageous because patients with corneal inflammation are typically photophobic. The self-assembling, fully defined, synthetic collagen analog is much less costly than human recombinant collagen and reduces the risk of immune rejection associated with xenogeneic materials. In situ gelation potentially allows for clinical application in outpatient clinics instead of operating theaters, maximizing practicality, and minimizing health care costs.