Penedones A, et al. - Via performing a systematic review and meta-analysis, researchers sought to determine the risk of nonarteritic anterior ischaemic optic neuropathy linked with phosphodiesterase type 5 inhibitors exposure. Exploring MEDLINE, EMBASE, Toxline, and VigiBase, they identified four observational studies, 50 case reports, and 608 spontaneous reports. Evaluation of males treated for erectile dysfunction was performed in all observational studies. No increased risk of definitive nonarteritic anterior ischaemic optic neuropathy was reported in correlation with treatment with phosphodiesterase type 5 inhibitors. Three studies were reported to be of good methodological quality. Risk factors to develop nonarteritic anterior ischaemic optic neuropathy were not evident in 12 (23%) patients among case reports.