The association between corneal neovascularization and visual acuity: a systematic review

. Purpose: Corneal neovascularization (CNV) is thought to negatively influence visual acuity. New therapeutic options that offer a differentiated influence on the ingrowths or regression of either corneal blood or lymphatic vessels force us to re-evaluate the association between CNV and visual acuity. Methods: A systematic review was conducted. Electronic databases were searched up to August 2009. Given the heterogeneity in study populations, interventions and measures of association, we were unable to undertake meta-analysis. The association between CNV and visual acuity was reported descriptively for each study. Results: Eleven studies using either vascular endothelial growth factor inhibitor treatments (i.e. bevacizumab, Avastin (R); HoffmannLa Roche AG, Basel, Switzerland) or an antiangiogenic treatment based on IRS-1 modulation [Gene-Signal (GS) 101, Aganirsen (R); GeneSignal, Evry (Paris), France] in a total of 131 patients (142 eyes) with corneal neovascularization were included. Ten of the eleven studies reported evidence of a statistically significant reduction in neovascularization following treatment. However, only four studies reported a statistically significant improvement in visual acuity following therapy. We found no studies that assessed the patient-level association between the change in neovascularization and visual acuity. Conclusion: This systematic review found that there is currently weak evidence to support the hypothesis that in patients with pathological neovascularization, a treatment-related reduction in neovascularization is associated with an increase in visual acuity. There is a need for future appropriately designed studies.