Evaluation of the peripapillary circulation in healthy and glaucoma eyes

In order to study peripapillary perfusion, one randomly selected eye of 34 healthy volunteers and 40 glaucoma patients (27 suffering from primary open-angle glaucoma (POAG) 10 from normal pressure glaucoma (NPG) and three from other types of glaucoma) was studied with a Heidelberg Retina Flowmeter. Temporal flow adjacent to the disc edge was significantly higher than the nasal flow (p < 0.01). It was reduced significantly in myopia both in controls (p < 0.05) and in glaucoma patients (p < 0.001). However, there was no difference between either controls and glaucoma patients or between POAG and NPG patients. It was independent of treatment type in glaucoma. Within the temporal peripapillary area extremely high flow values (values higher than the mean + 2 SD of the corresponding individual retinal flow) seemed to represent deep peripapillary vascular rings. They were significantly more frequent in glaucoma (72%) than in healthy volunteers (44%, p < 0.05). Their frequency was 83% in myopic and 23% in non-myopic eyes in the control group (p < 0.001). However, in glaucoma patients they were common both in myopic eyes (71%) and in non-myopic ones (75%). The results suggest that capillary perfusion adjacent to the temporal edge of the disc is significantly reduced in myopia. Deep peripapillary vascular structures can be measured on images focused on the surface of the retina, especially if the retina is thinner than normal (healthy myopic eyes and glaucomatous eyes independently of the refraction). This may mask a deficient function of the retinal capillary bed.