Depth position of spontaneous venous pulsations in ocular hypertensives and control-group discs.

Spontaneous venous pulsation can be observed at the site of entry of retinal veins into the physiological cup of the optic disc. Although it has been speculated that spontaneous vessel pulsation is related to primary open-angle glaucoma, no evaluation has been done on the depth position of such a pulsation inside the cup and its relationship to the intraocular pressure. Using laser scanning tomography, we measured the depth position of the maximal spontaneous vessel pulsation inside the optic cup in 24 discs of 24 patients, including 15 ocular hypertensives and 9 controls. The two groups did not differ significantly in age or refraction. The depth position of the maximal venous collapse, however, showed a significant difference between the two groups (p < 0.005), the mean value being 301 +/- 95 microns beyond the first retinal vessel reflection in the control-group eyes and 507 +/- 193 microns in the ocular hypertensive discs. The location of the depth position of the maximal venous collapse within the excavation could be a parameter that indicates the individual pressure tolerance of the ocular tissues.