Transepithelial versus Epithelium-off Corneal Collagen Cross-linking for Corneal Ectasia: A Systematic Review and Meta-analysis.

TOPIC: To evaluate the safety and efficacy of transepithelial corneal cross-linking in comparison with the established epithelium-off technique for corneal ectasia. CLINICAL RELEVANCE: Considerable debate exists regarding whether transepithelial and epithelium-off cross-linking are comparable in their safety and efficacy. METHODS: We searched 16 electronic databases, including Medline, Embase, Web of Science, and the grey literature, current to July 8, 2020, for randomized controlled trials comparing transepithelial and epithelium-off cross-linking for corneal ectasia. We excluded studies evaluating cross-linking for nonectatic indications, as well as non-randomized controlled trials. Our primary outcome was the change in maximal keratometry (Kmax) at 12 months after cross-linking, and we considered additional topographic, visual, and safety outcomes. We summarized our analyses by calculating weighted mean differences (MDs) with associated 95% confidence intervals (CIs) for continuous outcomes and relative risks (RRs) with corresponding 95% CIs for dichotomous outcomes. We conducted trial sequential analysis to determine whether the required information size was met for each outcome. The quality of individual trials was evaluated using the Cochrane Collaboration's risk of bias assessment tool, and the evidence was assessed at an outcome level using the Grading of Recommendations Assessment, Development, and Evaluation methodology. RESULTS: Twelve studies totaling 966 eyes were eligible. A significant difference was found between transepithelial and epithelium-off cross-linking groups in the change in Kmax at 12 months (MD, 0.75; 95% CI, 0.23-1.28; P = 0.004; primary outcome) and at longest follow-up (MD, 1.20; 95% CI, 0.62-1.77; P < 0.001; secondary outcome) after treatment. No significant difference was found between the 2 groups when examining uncorrected distance visual acuity (MD, 0.04; 95% CI, -0.06 to 0.14; P = 0.386) or corrected distance visual acuity (MD, 0.01; 95% CI, -0.06 to 0.09; P = 0.732). Transepithelial cross-linking was associated with significantly fewer complications than the epithelium-off approach (RR, 0.22; 95% CI, 0.06-0.79; P = 0.020), although it was associated with an increased rate of disease progression at 12 months after treatment (RR, 4.49; 95% CI, 1.24-16.25; P = 0.022). The required information size was met for our primary outcome and trial sequential analysis supported the conventional meta-analysis. The quality of evidence was rated as moderate using the Grading of Recommendations Assessment, Development, and Evaluation methodology. DISCUSSION: The efficacy of transepithelial cross-linking remains inferior to the epithelium-off approach, although it is significantly safer.

Selective Laser Trabeculoplasty versus Argon Laser Trabeculoplasty in Glaucoma Patients Treated Previously with 360° Selective Laser Trabeculoplasty: A Randomized, Single-Blind, Equivalence Clinical Trial.

PURPOSE: The effectiveness of selective laser trabeculoplasty (SLT) was compared with argon laser trabeculoplasty (ALT) in a randomized clinical trial for patients with medically uncontrolled open-angle glaucoma who have previously received 360° SLT. DESIGN: An active equivalence parallel armed randomized control trial. PARTICIPANTS: Patients with open-angle glaucoma including pigmentary dispersion syndrome and pseudoexfoliation syndrome were enrolled into the study from 7 different sites across Canada. METHODS: One setting of 180° of either SLT or ALT was assigned randomly and applied to each participant. MAIN OUTCOME MEASURES: The change in intraocular pressure (IOP) from baseline to 12 months was compared between the 2 groups. RESULTS: A total of 132 patients were recruited, 2 of which dropped out early in the study, leaving 130 patients who completed the study as per protocol. For those, the study's primary outcome was calculated. The IOP change at 1 year in comparison to baseline for SLT vs. ALT was found to be different by 0.33 mmHg between the 2 groups (3.16 for SLT and 2.83 for ALT) and was not statistically significant (P = 0.71) Further analysis, though, showed that SLT had a significantly lower IOP reduction at early time points: 1 week and 1 month, but this effect was lost by 3 months. Corresponding to this finding was the strong trend for ALT to fail more quickly than SLT. Although repeatable, the first repeat SLT reduced IOP to only about half compared with initial SLT treatment. CONCLUSIONS: The comparison at 12 months following the laser therapy showed that both modalities lowered the IOP with approximately 3 mmHg, yet essentially all of the time-to-failure analyses favored SLT over ALT. The repeat SLT effect was found to be half of the initial treatment.

Corneal biomechanical properties after SMILE versus FLEX, LASIK, LASEK, or PRK: a systematic review and 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; I2 = 78%), versus LASIK was 1.31 (95% CI, 0.54 to 2.08; p < 0.001; I2 = 77%), versus femtosecond lenticule extraction (FLEX) was - 0.01 (95% CI, - 0.31 to 0.30; p = 0.972; I2 = 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; I2 = 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, I2 = 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.

The temporal evolution of structural and functional measures after acute optic neuritis.

BACKGROUND: In this prospective case series, we aimed to characterise the temporal evolution of functional and structural measures in the afferent visual pathway of patients with acute optic neuritis (ON). METHODS: Fifty patients with ON were followed over 12 months. Testing with spectral-domain optical coherence tomography, Early Treatment Diabetic Retinopathy Study logarithm of the minimum angle of resolution (LogMAR) visual acuity and Humphrey perimetry central 30-2 threshold (SITA strategy) was performed at baseline, 3, 6 and 12 months after symptom onset. The main outcome measure was mean peripapillary retinal nerve fibre layer (RNFL) thickness in ON eyes. Secondary outcomes included mean ganglion cell layer (GCL) thickness, LogMAR visual acuity, and Humphrey perimetry measured visual field mean deviation (VFMD). Survival analyses were performed to Kaplan-Meier curves and variables in the models were tested using the log-rank test. RESULTS: Over 12 months, RNFL and GCL values progressively declined in ON eyes, and intereye differences were significantly different across all time points. When functional recovery was defined as a VFMD better than -5.00 dB in ON eyes, the mean recovery time for the entire cohort was 3 months (survival was 48%, SE=0.09, 95% CI 0.30 to 0.64). There were significant differences in cumulative recovery when comparisons were made between genders: 3 months after symptom onset there was a higher percentage cumulative recovery for female (75%) versus male (25%) patients. CONCLUSIONS: Structural and functional measures evolve over time in patients with ON. There may be sex-specific differences in recovery after an acute ON event.

Repeat Selective Laser Trabeculoplasty for Glaucoma Patients: A Systematic Review and Meta-analysis.

AIM AND OBJECTIVE: To evaluate repeat selective laser trabeculoplasty (SLT) for treating primary open-angle glaucoma (POAG). MATERIALS AND METHODS: PubMed, CINAHL, and EMBASE were systematically searched along with grey literature. All English articles that measured intraocular pressure (IOP) before and after repeat SLT on adult patients with POAG were included. Studies were not filtered by location or publication date. Covidence was used to screen imported articles. Risk of bias assessment and data extraction was performed after screening. Meta-analysis was performed using STATA 16.0. Fixed-effect or random-effects models were developed depending on the presence of heterogeneity. RESULTS: Database and grey literature search identified 512 unique studies. After duplicate removal and screening, 12 articles were included and data from included studies were synthesized. Nine articles were included in the meta-analysis. Three studies were prospective observational studies, and nine studies were retrospective chart reviews. Due to the presence of heterogeneity, a random-effects model has been utilized that suggested significant IOP reduction (IOPR) by repeat SLT at 24 months follow-up. CONCLUSION: Based on our results, repeat SLT could be an effective procedure in reducing IOP for patients with glaucoma for up to 24 months. Efficacy of third, fourth, or further SLT remains to be verified. More data from long-term, high-quality randomized-controlled trials (RCTs) are required to make conclusions. CLINICAL SIGNIFICANCE: Repeat SLT may be an effective treatment for lowering IOP with minimal complications or safety issues. This may allow the use of SLT as a primary treatment for POGA, allowing the discontinuation of medications or eye drops and lead to additional benefits. HOW TO CITE THIS ARTICLE: Jang HJ, Yu B, Hodge W, et al. Repeat Selective Laser Trabeculoplasty for Glaucoma Patients: A Systematic Review and Meta-analysis. J Curr Glaucoma Pract 2021;15(3):117-124.

Biometric characteristics of eyes with exfoliation syndrome and occludable as well as open angles and eyes with primary open-angle glaucoma.

OBJECTIVE: To describe differences in axial length scan (A-scan) and ultrasound biomicroscopy (UBM) parameters in eyes with exfoliation syndrome (XFS) and occludable angles (XFSOc), XFS and open angles (XFSOp), and eyes with primary open-angle glaucoma (POAG). DESIGN: Cross-sectional descriptive study. PARTICIPANTS: Seventy-two eyes of 72 patients (mostly Caucasians) were identified through glaucoma clinics at the University of Ottawa;19 eyes had XFSOc, 31 eyes XFSOp, and 22 eyes POAG. METHODS: After a detailed ophthalmic history and examination, A-scan biometry and UBM were done to assess anterior segment parameters: central anterior chamber depth (ACD), lens thickness, trabecular meshwork-iris angle, and angle opening distance (AOD). Lens/axial length factor and the relative lens position were calculated. The above measurements were compared across the 3 groups. RESULTS: We found statistically significant differences in measurements among the groups. ACD was shallowest in eyes with XFSOc (1.88 [SD 0.07] mm), followed by XFSOp (2.37 [SD 0.05] mm), and POAG (2.64 [SD 0.08] mm). XFSOc had thicker lenses (5.28 [SD 0.09] mm) compared with the other groups: XFSOp (5.03 [SD 0.06] mm) and POAG (4.84 [SD 0.09] mm). Lens/axial length factor was highest in XFSOc (2.34 [SD 0.05] mm) versus XFSOp (2.12 [SD 0.03] mm) and POAG (2.02 [SD 0.05] mm); relative lens position was lowest in XFSOc (2.27 [SD 0.03] mm) versus XFSOp (2.31 [SD 0.02] mm) and POAG (2.36 [SD 0.03] mm). CONCLUSIONS: Eyes with XFSOc in our study demonstrated lens thickening and shallow central ACD versus eyes with XFSOp and eyes with POAG. This suggests the possibility that cataract formation and (or) zonular weakness may contribute to the development of an occludable angle in eyes with XFS.

Large cell carcinoma of the lung and squamous cell carcinoma of the oropharynx presenting as uveitis.

Ocular manifestations of systemic malignancy may precede the diagnosis of cancer; some intraocular lymphomas can present initially as chronic uveitis. The two cases described were found to have underlying carcinomas of the lung and oropharynx. Both presented with chronic uveitis and decreased visual acuity that were not responding to antiinflammatory therapy.

Transepithelial versus epithelium-off corneal collagen cross-linking for corneal ectasia: protocol for a systematic review, meta-analysis and trial sequential analysis of randomised controlled trials.

INTRODUCTION: Corneal ectasias are progressive, degenerative ocular diseases defined by abnormal structural changes in the cornea, leading to distortion of vision and substantial reduction in quality of life. Corneal collagen cross-linking (CXL) increases the biomechanical rigidity of the cornea and has been shown to halt ectatic processes. The established CXL protocol requires removal of the corneal epithelium. However, some surgeons have proposed transepithelial approaches to enhance patient recovery and minimise adverse events. Whether novel transepithelial approaches are as effective in arresting ectasia as the established epithelium-off protocol remains unclear. This study will systematically review the evidence on transepithelial CXL approaches and compare it to the epithelium-off protocol. METHODS AND ANALYSIS: We will include randomised controlled trials (RCTs) comparing transepithelial and epithelium-off CXL for any corneal ectasia. We will search 16 electronic databases including MEDLINE and Embase, as well as the grey literature. Two reviewers will independently screen search results to identify eligible studies, complete data abstraction and conduct quality assessment. We will assess the quality of individual RCTs using the Cochrane risk of bias assessment tool. Our primary outcome will be the change in maximal keratometry at 12 months after treatment, and we will examine 11 additional outcomes. We will summarise our analyses by measures of association (relative risk or odds ratio) and corresponding 95% confidence intervals (CIs) for dichotomous outcomes and weighted mean differences with 95% CIs for continuous outcomes. Prespecified subgroup analyses will be conducted to explore heterogeneity. The overall quality of evidence will be rated using the Grading of Recommendations Assessment, Development and Evaluation approach. ETHICS AND DISSEMINATION: Ethics approval is not required for this systematic review as it draws from previously published data. Results of the study will be submitted to a peer-reviewed journal for publication and discussed at conferences and seminars. PROSPERO REGISTRATION NUMBER: CRD42018102069.

Retinal nerve fiber layer and future risk of multiple sclerosis.

BACKGROUND: Optical coherence tomography (OCT)--measured retinal nerve fiber layer (RNFL) values may represent a surrogate biomarker for axonal integrity in multiple sclerosis (MS). The purpose of this study was to determine whether RNFL measurements obtained within two years of an optic neuritis (ON) event distinguish patients at increased risk of developing clinically-definite MS (CDMS). METHODS: Fifty consecutively sampled patients who experienced a single ON event were followed prospectively for a mean period of 34 months with OCT testing. Values of RNFL in clinically-affected and non-affected eyes were compared between patients who developed CDMS and those that did not develop MS after ON. FINDINGS: Twenty-one patients (42%) developed CDMS during the course of the study, with a mean conversion time of 27 months. Mean RNFL values were thinner in the clinically-affected eyes of non-MS patients than CDMS eyes after one year (p = 0.0462) due to more severe ON events in the former. By year two, CDMS patients manifested more recurrent ON events and RNFL thinning than non-MS patients. Temporal RNFL values were thinner in the non-affected eyes of CDMS patients with a trend towards significance (p = 0.1302). INTERPRETATION: Our results indicate that RNFL thickness does not reliably distinguish patients at higher risk of converting to CDMS after ON. The severity of ON has a greater effect on RNFL thickness than risk of CDMS at one year. The CDMS patients demonstrate progressive RNFL thinning likely due to recurrent sub-clinical ON events, which may help differentiate them from non-MS patients over time.

Generalized posterior keratoconus: clinical pathologic correlations.

CASE REPORT: A 73-year-old woman presented with bilateral generalized posterior keratoconus. The corneal thickness measured 0.320 mm paracentrally and 0.440 mm toward the periphery. The corneal specimen revealed absence of Bowman's layer and focal homogeneous oval stromal deposits that stained for amyloid. COMMENTS: Our case of generalized posterior keratoconus shows absence of Bowman's layer. The amyloid deposits, which also were noted clinically in the cornea of the fellow right eye, were most consistent with a diagnosis of polymorphous amyloid degeneration. To our knowledge, this is the first histopathological report of generalized posterior keratoconus.

Prostaglandin analogues for ophthalmic use: a cost-effectiveness analysis.

BACKGROUND: The objective of this study was to perform an economic analysis of the cost-effectiveness of prostaglandin analogues for the treatment of increased intraocular pressure (IOP). Prostaglandin analogues for ophthalmic use are more costly than alternative agents for the lowering of IOP. An important policy decision is whether to support continued open listing of these agents or to restrict them to limited use status. METHODS: The cost-effectiveness of prostaglandin analogues was assessed using a decision analytic model. Latanoprost was compared with timolol, dorzolamide, and brimonidine, and travoprost was compared with timolol separately. The effectiveness data used for this economic analysis were the number of millilitres of mercury of IOP reduction compared with baseline and the incidence of adverse events resulting in a withdrawal of the patient from the study. Sensitivity analyses were conducted to assess the robustness of the study results. RESULTS: Compared with latanoprost, dorzolamide was not a cost-effective strategy. Compared with brimonidine, latanoprost provided a higher IOP reduction with an incremental cost-effectiveness ratio of $16.17 (base case), but the additional IOP reduction with latanoprost was obtained at a cost higher than the average cost per millimetre of mercury reduction obtained with brimonidine. Compared with timolol, latanoprost and travoprost had a positive incremental cost-effectiveness ratio of $34.48 and $39.06, respectively. INTERPRETATION: For the first-line treatment of glaucoma and elevated IOP, latanoprost is a more cost-effective strategy than dorzolamide and brimonidine. Latanoprost and travoprost are more effective than timolol but also more expensive. For those for whom timolol is not contraindicated, it would be preferable, from a cost-effectiveness standpoint, to initiate treatment with timolol and reserve the prostaglandin analogues as an alternative treatment or as add-on therapy for patients not achieving a clinical response with timolol. Better treatment compliance associated with these analogues improves their cost-effectiveness.

Tranexamic acid in the treatment of pediatric traumatic hyphema.

BACKGROUND: This study was undertaken to determine whether a difference exists in treatment outcome between patients treated with tranexamic acid (TEA) plus topical steroids and those treated with topical steroids alone. METHODS: A retrospective cohort study was conducted to compare treatment results for children with traumatic hyphema treated with TEA and topical steroids versus topical steroids alone. Patients were identified from a chart review of the Children's Hospital of Eastern Ontario eye clinic and the Queen's Department of Ophthalmology emergency eye clinic for charts coded "traumatic hyphema." The primary outcomes measured included visual acuity, rebleed rate, intraocular pressure, and time to hyphema resolution. Covariates were hyphema grade, the need for medications to lower intraocular pressure, and the presence of associated ocular traumatic complications. Analysis was performed with both bivariate analysis and multivariate models. RESULTS: Two hundred and fifteen patients with traumatic hyphema were included in our study. One hundred and thirty-seven patients (63.1%) received TEA plus topical steroids, and the remaining 78 patients received topical steroids alone. There was no significant difference in rebleed rate between the TEA plus topical steroid group (1.6%) and the steroid-alone group (2.6%, p = 0.60). INTERPRETATION: Patients with traumatic hyphema treated with TEA plus topical steroids did not have a significantly lower incidence of rebleed than those treated with topical steroids alone.

A Systematic Review Regarding Tonometry and the Transmission of Infectious Diseases.

Tonometry has been identified as a common method for measuring the intraocular pressure in patients. The direct contact between the tonometer and the eye may contribute to the risk of cross infection, especially of viral particles, from one patient to another. A systematic review was undertaken to address the likelihood of human immunodeficiency virus (HIV), hepatitis B virus, hepatitis C virus, and prion diseases transmission through the use of tonometers. Additionally, a comparison of the current tonometer disinfection methods is provided to assist with identifying which technique effectively reduces the risk of disease transmission. An electronic literature search was conducted using the following databases: Web of Science, EMBASE, CINAHL, SCOPUS, Biosis Previews, Cochrane Library, PubMed, and Google Scholar. Dissertation indexes were also searched, and these included: Dissertations and Abstracts, and Dissertations and Abstracts - UK/Ireland. Additionally, the Clinicaltrials.gov trial registry was searched to identify any other relevant literature. Two independent reviewers critically appraised the articles retrieved through the literature search. In total, 11 unique studies were deemed relevant for this systematic review. The available evidence demonstrated that the use of tonometers contributes to the transmission of these infectious diseases in vitro. The results also demonstrated variability in determining the most effective tonometer sterilization technique against these infectious diseases in vitro. There was limited evidence available regarding the transmission of HIV, hepatitis B, hepatitis C, and prion diseases through the use of tonometers. Additionally, due to the variability regarding the most effective sterilization techniques, it is difficult to identify which sterilization technique is most effective or adequately effective against these infectious diseases. Future research studies regarding infectious disease transmission through tonometry and sterilization techniques should be completed to more adequately inform infectious disease control guidelines.

The consequences of waiting for cataract surgery: a systematic review.

BACKGROUND: Cataract surgery is the most common operative procedure performed in Canada, and how patients are affected by wait times for this surgery has important clinical, public health and health policy considerations. We conducted a systematic review to understand the relation between wait time for cataract surgery and patient outcomes and the variables that modify this relation. METHODS: We performed an electronic search of 11 databases and the proceedings of 4 conferences. The search was restricted to studies published after the transition to phacoemulsification (1990). We assessed the quality of the included studies using the Jadad Scale for randomized controlled trials and the Newcastle-Ottawa Scale for cohort and case-control studies. The data were found to be inappropriate for meta-analysis, thus we performed a qualitative synthesis. RESULTS: We found a total of 27 studies that met our inclusion criteria. When these studies were reviewed, a dichotomy was observed for the wait time-outcome relation: outcomes associated with wait times of or= 6 months. Patients who waited more than 6 months to receive cataract surgery experienced more vision loss, a reduced quality of life and had an increased rate of falls compared with patients who had wait times of less than 6 weeks. The outcomes associated with wait times between 6 weeks and 6 months remain unclear. INTERPRETATION: Patients who wait more than 6 months for cataract surgery may experience negative outcomes during the wait period, including vision loss, a reduced quality of life and an increased rate of falls.

The pathway to RCTs: how many roads are there? Examining the homogeneity of RCT justification.

BACKGROUND: Randomized controlled trials (RCTs) form the foundational background of modern medical practice. They are considered the highest quality of evidence, and their results help inform decisions concerning drug development and use, preventive therapies, and screening programs. However, the inputs that justify an RCT to be conducted have not been studied. METHODS: We reviewed the MEDLINE and EMBASE databases across six specialties (Ophthalmology, Otorhinolaryngology (ENT), General Surgery, Psychiatry, Obstetrics-Gynecology (OB-GYN), and Internal Medicine) and randomly chose 25 RCTs from each specialty except for Otorhinolaryngology (20 studies) and Internal Medicine (28 studies). For each RCT, we recorded information relating to the justification for conducting RCTs such as average study size cited, number of studies cited, and types of studies cited. The justification varied widely both within and between specialties. RESULTS: For Ophthalmology and OB-GYN, the average study sizes cited were around 1100 patients, whereas they were around 500 patients for Psychiatry and General Surgery. Between specialties, the average number of studies cited ranged from around 4.5 for ENT to around 10 for Ophthalmology, but the standard deviations were large, indicating that there was even more discrepancy within each specialty. When standardizing by the sample size of the RCT, some of the discrepancies between and within specialties can be explained, but not all. On average, Ophthalmology papers cited review articles the most (2.96 studies per RCT) compared to less than 1.5 studies per RCT for all other specialties. CONCLUSIONS: The justifications for RCTs vary widely both within and between specialties, and the justification for conducting RCTs is not standardized.

The value of corneoscleral rim cultures in keratoplasty: a systematic review and cost-effectiveness analysis.

PURPOSE: This study evaluated the performance of donor corneoscleral rim cultures for predicting infection after corneal transplantation, and determines if there is a correlation between positive corneoscleral rim cultures and postkeratoplasty infection. DESIGN AND DATA SOURCES: This was a systematic review, prognostic accuracy analysis, and cost-effectiveness analysis. Databases searched were: Medline (Ovid), Embase (Ovid), CINAHL, Cochrane Library, Web of Science, and BioSis Previews. Grey literature was also explored. MATERIALS AND METHODS: A systematic review was conducted to locate published and unpublished studies. All studies examining corneal button contamination and its association with endophthalmitis and keratitis posttransplantation were included. Extracted data were used to calculate sensitivity, specificity, positive predictive value, and negative predictive value. Cost data from the London Laboratory Services Group in London, ON were used to calculate the cost-effectiveness of culturing donor rim cultures. RESULTS: Of 7,870 grafts, 954 had a positive rim culture (12.1%), with 12 patients going on to develop keratitis or endophthalmitis (1.3%). The prevalence of keratitis and endophthalmitis in this study was 0.15%, and the positive predictive value 1.5%. Of the 12 infections, nine were fungal and three bacterial. The estimated cost of a positive and negative test result was CAD$45.99 and $14.15, respectively. The cost to run all 7,870 tests was estimated to be $141,735.86, with an incremental cost-effectiveness ratio of $40,215.70. CONCLUSION: There was a significant divergence between bacterial and fungal rim-culture results. Bacterial cultures predicted clinical infection poorly, did not change management, and were expensive. Fungal cultures predicted clinical infection in over 10% of patients, had the potential to change management, and were 40% less expensive than full rim culturing (bacterial and fungal tests). Fungal rim cultures may be considered in areas where fungal infection rates are high.

Correction: Summary of Glaucoma Diagnostic Testing Accuracy: An Evidence-Based Meta-Analysis.

[This corrects the article DOI: 10.14740/jocmr2643w.].

A simple, cross-linked collagen tissue substitute for corneal implantation.

PURPOSE: To develop a simple corneal substitute from cross-linked collagen. METHODS: Porcine type I collagen (10%; pH 5), was mixed with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The final homogenous solution was molded to corneal dimensions, cured, and then implanted into rabbits and minipigs by lamellar keratoplasty. The implants were followed for up to 6 months after surgery. Clinical examinations of the cornea included detailed slit lamp biomicroscopy, in vivo confocal microscopy, topography and esthesiometry for nerve function. Histopathologic examinations were also performed on rabbit corneas harvested after 6 months. RESULTS: Cross-linked collagen (refractive index, 1.35) had optical clarity superior to human corneas. Implanted into rabbit and porcine corneas, only 1 of 24 of the surgical corneas showed a slight haze at 6 months after surgery. All other implants showed no adverse reactions and remained optically clear. Topography showed a smooth surface and a profile similar to that of the contralateral nonsurgical eye. The implanted matrices promoted regeneration of corneal cells, tear film, and nerves. Touch sensitivity was restored, indicating some restoration of function. The corneas with implants showed no significant loss of thickness and demonstrated stable host-graft integration. CONCLUSIONS: Collagen can be adequately stabilized, using water soluble carbodiimides as protein cross-linking reagents, in the fabrication of corneal matrix substitutes for implantation. The simple cross-linking methodology would allow for easy fabrication of matrices for transplantation in centers where there is a shortage of corneas, or where there is need for temporary patches to repair perforations in emergency situations.