OBJECTIVE To evaluate the effect of ageing on the retinal vascular responsiveness to flicker light in glaucoma and ocular hypertension (OHT). METHODS Retinal vascular response to flicker was measured with the retinal vessel analyser in 56 healthy subjects (59 ± 9 years), 50 primary open-angle glaucoma (POAG) (60 ± 10 years) and 46 OHT patients (62 ± 9 years). In the glaucoma group, the less damaged eye; in the OHT group, the eye with the higher intraocular pressure; and in healthy controls, one randomly selected eye was considered. Parametric and non-parametric linear regression analysis, as well as a model of covariance analysis (ANCOVA) was used to evaluate the effect of age on the vascular response. RESULTS In all three groups (N=152) absolute (Pearson R: -0.19, p<0.019; Spearman R: -0.22, p<0.006) and relative change (Pearson R: -0.18, p<0.027; Spearman R: -0.21, p<0.010) were statistically associated with age. The ANCOVA showed no difference between the three groups in this regard (absolute change: p=0.43; relative change: p=0.51). CONCLUSIONS Vascular responsiveness to flicker light decreases with age in healthy individuals, in glaucoma patients and in OHT patients. This effect seems to be comparable between the tested groups, and age-related change in vascular responsiveness to flicker light seems an unlikely risk factor for glaucoma.