Topical Insulin for Glaucoma

Inclusion Criteria: * Capable to provide informed consent * Diagnosis of optic neuropathy either glaucoma or NAION or optic disc drusen. * Only one eye per patient will be selected as the study eye - if both eyes meet the inclusion criteria, the eye with the worse acuity and /or visual field will be selected. The contralateral eye will be left untouched. Exclusion Criteria: * Pregnant or breastfeeding woman * Presence of any ocular pathologies other than glaucoma that contributes to the severe vision loss (retinopathy / maculopathy, severe uveitis, keratopathy, etc.) * Diagnosis of glucose intolerance, type 1 or 2 diabetes mellitus * Inability to perform reliable visual field * Unable to provide informed consent * Unable to complete the tests and follow-ups required by the study