Narrative review after post-hoc trial analysis of factors that predict corneal endothelial cell loss after phacoemulsification: Tips for improving cataract surgery research.

PURPOSE: Identifying pre/perioperative factors that predict corneal endothelial-cell loss (ECL) after phacoemulsification may reveal ways to reduce ECL. Our literature analysis showed that 37 studies have investigated one or several such factors but all have significant limitations. Therefore, the data of a large randomized controlled trial (PERCEPOLIS) were subjected to post-hoc multivariate analysis determining the ability of nine pre/perioperative variables to predict ECL. METHODS: PERCEPOLIS was conducted in 2015-2016 to compare two phacoemulsification techniques (subluxation and divide-and-conquer) in terms of 3-month ECL. Non-inferiority between the techniques was found. In the present study, post-hoc univariate and multivariate analyses were conducted to determine associations between ECL and age, sex, cataract density, preoperative endothelial-cell density, phacoemulsification technique, effective phaco time (EPT), and 2-hour central-corneal thickness. The data are presented in the context of a narrative review of the literature. RESULTS: Three-month data were available for 275 patients (94% of the randomized cohort; mean age, 74 years; 58% women). Mean LOCSIII cataract grade was 3.2. Mean EPT was 6 seconds. Mean ECL was 13%. Only an older age (beta = 0.2%, p = 0.049) and higher EPT (beta = 1.2%, p = 0.0002) predicted 3-month ECL. Cataract density was significant on univariate (p = 0.04) but not multivariate analysis. The other variables did not associate with ECL. CONCLUSIONS: Older age may amplify ECL due to increased endothelial cell fragility. EPT may promote ECL via cataract density-dependent and -independent mechanisms that should be considered in future phacoemulsification research aiming to reduce ECL. Our literature analysis showed that the average ECL for relatively unselected consecutively-sampled cohorts is 12%.

Prevalence and predictive factors for posterior vitreous attachment in eyes undergoing epiretinal membrane surgery.

BACKGROUND: To report the prevalence of posterior vitreous attachment (PVA) in patients with idiopathic epiretinal membrane (iERM) and to determine associated preoperative predictive factors. METHODS: Retrospective observational case series of 408 eyes who underwent surgery for iERM without vitreomacular traction. The status of the posterior hyaloid was assessed intraoperatively. Predictive factors were analysed using univariate and multivariate logistic regression. We also evaluated the effect of PVA on the anatomical and functional outcomes of surgery. RESULTS: Eighty-two (20.1%) eyes were found to have an undetached posterior hyaloid during vitrectomy. In multivariate analysis, axial length (AL) and lens status were strongly associated with the posterior vitreous status (p = 0.031 and p = 0.048). The odds of having a PVA decreased by a factor 0.81 per mm of AL (95% CI, 0.66-1.00). Phakic eyes had a 2.88-fold increased risk of exhibiting PVA compared to those with previous cataract extraction (95% CI, 1.10-7.52). The presence of PVA did not have any effect on postoperative anatomical and functional outcomes. In contrast, we found that eyes with shorter axial length, low preoperative visual acuity and disruption of the ellipsoid zone exhibited worse visual recovery (p = 0.006, p < 0.001 and p = 0.037). CONCLUSION: PVA was observed in 20.1% of eyes undergoing vitrectomy for iERM. Shorter AL and phakic status were strong predictive factors of PVA in those eyes. However, the morphological features and the surgical prognosis of iERMs with PVA did not differ from those with posterior vitreous detachment.