A comparison of retinal and choroidal hemodynamics in patients with primary open-angle glaucoma and normal-pressure glaucoma.

PURPOSE

To quantify, compare, and assess differences between retinal and choroidal hemodynamics in normal control subjects and patients with ocular hypertension, primary open-angle glaucoma, and normal-pressure glaucoma.

METHODS

Video fluorescein angiograms were made in 20 normal subjects, 11 patients with ocular hypertension, 45 patients with primary open-angle glaucoma, and 43 patients with normal-pressure glaucoma. Choroidal dye build-up curves were analyzed using an exponential model. The model time constant tau reflected the local blood refreshment time, the time needed to replace the blood volume in a tissue volume. Retinal arteriovenous passage time was estimated from the time lapse between retinal arterial and venous dye curves.

RESULTS

The retinal arteriovenous passage time was longer in patients with primary open-angle glaucoma compared with normal subjects and patients with normal-pressure glaucoma; the average arteriovenous passage times (+/-SEM) in normal subjects and in patients with ocular hypertension, primary open-angle glaucoma, and normal-pressure glaucoma were, respectively, 2.44 +/- 0.19, 2.90 +/- 0.37, 3.02 +/- 0.17, and 2.55 +/- 0.15 seconds. Choroidal tau was longest in the normal-pressure glaucoma group but not as long in the primary open-angle glaucoma group; tau values in normal subjects and patients with ocular hypertension, primary open-angle glaucoma, and normal-pressure glaucoma were, respectively, 4.6 +/- 0.29, 5.6 +/- 0.69, 6.2 +/- 0.39, and 7.1 +/- 0.33 seconds.

CONCLUSIONS

Whereas choroidal circulation is especially slower in patients with normal-pressure glaucoma, retinal circulation is delayed in patients with primary open-angle glaucoma. The choroidal and retinal vascular systems behave differently in primary open-angle and normal-pressure glaucoma, which may be important in the management of glaucoma.