Decreased choroidal blood flow associated with retinitis pigmentosa.

The intraocular pressure pulse has been measured and used to evaluate the ophthalmic arterial pressure and the ocular pulsatile blood flow in 13 retinitis pigmentosa patients and ten similar aged healthy volunteers. The light sensitivity thresholds of the central fields of all persons were recorded using the Heijl-Krakau automated perimeter. The mean pulse amplitudes of 1.2 +/- 0.2 (26) and 2.3 +/- 0.25 (20) mmHg in the affected and in the control groups respectively differed significantly (p less than 0.001). The corresponding pulsatile blood flows were 310 +/- 24 (26) and 628 +/- 40 (20) microliters min-1. The mean ophthalmic arterial pressures in the two groups were equal. The light sensitivities in pairs of eyes of four of the patients differed substantially and in all cases the eye with the better visual performance had the higher ocular pulsatile blood flow. It is concluded that relative choroidal ischaemia is closely associated with visual loss and pigment cell degeneration in patients with retinitis pigmentosa.