Dataset Information

Predicting Corneal Improvement after Descemet Membrane Endothelial Keratoplasty for Fuchs Endothelial Corneal Dystrophy

ABSTRACT:

Purpose

To develop a model to predict corneal improvement after Descemet membrane endothelial keratoplasty (DMEK) for Fuchs endothelial corneal dystrophy (FECD) from Scheimpflug tomography.

Design

Cross-sectional study.

Participants

Forty-eight eyes (derivation group) and 45 eyes (validation group) with a range of severity of FECD undergoing DMEK.

Methods

Scheimpflug images were obtained before and after DMEK. Before DMEK, pachymetry map and posterior elevation map patterns were quantified by a special image analysis program measuring tomographic features of edema (loss of regular isopachs, displacement of the thinnest point of the cornea, posterior surface depression). Image-derived novel parameters were combined with instrument-derived parameters, and the relative influences of parameters associated with the change in central corneal thickness (CCT) after DMEK in the derivation group were determined by using a gradient boosting machine learning model. The parameters with highest relative influence were then fit in a linear regression model. The derived model was applied to the validation group. Correlations and agreement were assessed between predicted and observed changes in CCT.

Main Outcome Measures

Predictive power (R2) and mean difference between predicted and observed change in CCT.

Results

The gradient boosting machine model identified 4 novel parameters of isopach circularity and eccentricity and 1 instrument-derived parameter (posterior surface radius); preoperative CCT was a poor predictor. In the derivation group, the model strongly predicted the change in CCT after DMEK (R2 = 0.80; 95% confidence interval [CI], 0.71–0.89) and the mean difference between predicted and observed change was, by definition, 0 μm. When the same 5 parameters were fit to the validation group, the model performed very highly (R2 = 0.89; 95% CI, 0.84–0.94). When the coefficient estimates from the derivation model were used to predict the change in CCT in the validation group, the predictive power was also high (R2 = 0.78; 95% CI, 0.68–0.88), and the mean difference was 4 μm (predicted minus observed).

Conclusions

Scheimpflug tomography maps of corneas with FECD can predict the improvement in CCT after DMEK, independent of preoperative corneal thickness measurement. The model could be applied in clinical practice or for clinical research of FECD.

SUBMITTER: Patel S

PROVIDER: S-EPMC9560526 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature

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Project description:ImportancePredicting the extent of corneal edema resolution after Descemet membrane endothelial keratoplasty (DMEK) may help in preoperative decision-making by identifying patients who may benefit from restoring endothelial function.ObjectiveTo develop and validate a predictive model for edema resolution after DMEK using Scheimpflug tomographic imaging.Design, setting, and participantsTwo prospective studies recruited participants with advanced Fuchs dystrophy at a university-based tertiary referral center between July 1, 2017, and August 31, 2019. Analyses were designed in November 2019 and completed on June 30, 2020. Development of a predictive model using linear least absolute shrinkage and selection operator regression was conducted in a derivation cohort (100 eyes). Overall performance, discrimination, and calibration were tested in the separate validation cohort (32 eyes).ExposuresPreoperative Scheimpflug parameters and patient-reported visual disability were considered as potential predictors of edema resolution: (1) tomographic features (irregularity of lines of equal corneal thickness, displacement of the thinnest point of corneal thickness from the inferior-temporal quadrant, and absolute amount of focal posterior corneal depression), (2) standardized anterior and posterior corneal backscatter, (3) preoperative central corneal thickness, and (4) Fuchs dystrophy-specific visual disability.Main outcomes and measuresDecrease in central corneal thickness after DMEK indicative of edema resolution.ResultsOf the 88 patients included in the analysis, 54 were women (61%); median age was 68 years (interquartile range [IQR], 59-76 years). A median of 13 months after DMEK (IQR, 9-16 months), median corneal thickness was 77 μm lower (IQR, 51-94 μm) in the derivation cohort and 75 μm lower in the validation cohort (IQR, 54-96 μm) than before surgery. Per 10-μm edema resolution, eyes gained 0.66 Early Treatment Diabetic Retinopathy Study letters (95% CI, 0.09-1.23) in best-corrected visual acuity. Three tomographic features were present in 68 of 100 eyes (68%) in the derivation cohort and in 18 of 32 eyes (56%) in the validation cohort before DMEK and in only 1 of 132 eyes (1%) after DMEK. To predict edema resolution after DMEK based on preoperative assessment, 5 variables were selected by the statistical learning algorithm: nonparallel isopachs, focal posterior depression, anterior and posterior corneal backscatter, and central corneal thickness. In the separate validation cohort, the model showed high overall performance, discrimination, and calibration.Conclusions and relevanceThese post hoc analyses of prospective cohorts support a model for use in the prediction of edema resolution after DMEK using Scheimpflug measurement to identify patients benefitting most from DMEK.

Project description:BackgroundIn patients with Fuchs endothelial corneal dystrophy (FECD), the most beneficial stage to perform Descemet membrane endothelial keratoplasty (DMEK) remains uncertain. The goal of this study was to compare the surgical outcomes after DMEK in FECD patients with subclinical corneal edema and clinical corneal edema to test the hypothesis of whether performing surgery in subclinical corneal edema stages achieves better surgical outcomes.MethodsIn this prospective, observational, single-institution cohort study, 106 pseudophakic eyes of 85 patients with FECD were divided into two groups depending on the presence of preoperative subclinical and clinical corneal edema. Subclinical corneal edema was diagnosed if more than one of the following criteria was present in Scheimpflug tomography: loss of regular isopachs, displacement of the thinnest point of the cornea, and focal posterior corneal surface depression. Clinical corneal edema was diagnosed with slit-lamp biomicroscopy. The primary outcome was the corrected distance visual acuity (CDVA) 4 months after DMEK. Secondary outcomes were central corneal thickness (CCT), thinnest corneal thickness (TCT), and total corneal density (TCD) in Scheimpflug tomography, as well as endothelial cell loss (ECL) and the re-bubbling rate. The differences between both groups were analyzed using clustered Wilcoxon rank-sum tests or a Chi-squared test.ResultsPostoperative CDVA was significantly better in the group with subclinical edema (0.18 ± 0.12 logMAR) compared to the group with clinical edema (0.24 ± 0.19 logMAR; P = 0.026). Four months after DMEK, TCD was higher in the group with preoperative clinical edema [31.7 ± 8.3 gray scale units (GSU)] compared to the group with subclinical edema (27.8 ± 6.1 GSU; P = 0.005). The postoperative CCT, TCT, ECL, and re-bubbling rates did not differ significantly between both groups (all P > 0.05).ConclusionsDMEK for FECD yielded better visual acuity after 4 months when performed in the early stage of FECD compared to a later stage with clinical edema. This may be attributable to persistent corneal fibrosis after DMEK in eyes with preoperative clinically evident corneal edema, as suggested by higher postoperative corneal density in eyes with clinical edema. Consequently, the findings advocate for the consideration of earlier DMEK in FECD patients to achieve better surgical recovery.

Project description:IntroductionIt remains uncertain whether Descemet membrane endothelial keratoplasty (DMEK) or Descemet stripping only (DSO) yields better outcomes in patients with symptomatic Fuchs endothelial corneal dystrophy (FECD). This paper presents the protocol for the Descemet Endothelial Thickness Comparison Trial II (DETECT II), a multicentre, outcome-masked, randomised, placebo-controlled, clinical trial comparing DMEK to DSO with ripasudil (DSO-R) for this patient population.Methods and analysisA total of 60 patients with endothelial dysfunction due to symptomatic FECD will be enrolled from seven participating sites in the USA. The patients will be randomly assigned in a 1:1 ratio to one of the following treatment groups: group 1-DMEK plus topical placebo and group 2-DSO plus topical ripasudil 0.4%. The enrolment period is 24 months. The primary outcome is best spectacle-corrected visual acuity at 12 months. Secondary outcomes include peripheral and central endothelial cell density, visual acuity, vision-related quality of life and Pentacam Scheimpflug tomography. Study outcomes will be analysed using mixed effects linear regression. Adverse events, including rebubble procedures, endothelial failure and graft rejection, will be documented and analysed using appropriate statistical methods. DETECT II aims to provide evidence on the comparative effectiveness of DMEK and DSO-R. The results of this trial will contribute to optimising the treatment of FECD, while also exploring the cost-effectiveness of these interventions. Dissemination of findings through peer-reviewed publications and national/international meetings will facilitate knowledge translation and guide clinical practice in the field of corneal transplantation.Ethics and disseminationA data and safety monitoring committee has been empanelled by the National Eye Institute. All study protocols will be subject to review and approval by WCG IRB as the single IRB of record. This study will comply with the National Institute of Health (NIH) Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. Data from the trial will be made available on reasonable request.Trial registration numberNCT05275972.