Variability of Doppler ophthalmic pressure index with occlusive carotid artery disease.

To evaluate day-to-day variability of Doppler ophthalmic pressure index by means of the ophthalmomanometry-Doppler technique, bilateral ophthalmic artery pressure and indirect systemic blood pressure determinations were repeated within 1 month in 40 patients with clinically stable occlusive carotid disease. No difference in Doppler ophthalmic pressure and calculated pressure index between both days could be demonstrated. The standard deviation of differences in ophthalmic pressure index between first and second day measurements was 0.04. Correlation between bilateral ophthalmic pressure index measurements on both days was high (r = 0.93, n = 80). It is concluded that individual Doppler ophthalmic pressure index must change at least 0.08 before it can be considered significant. In 37 patients with occlusive carotid artery disease (greater than 60% diameter reduction) undergoing 38 endarterectomies, Doppler ophthalmic pressure index was evaluated before and after surgery. Mean +/- SD ipsilateral Doppler ophthalmic pressure index increased from 0.59 +/- 0.07 to 0.71 +/- 0.05 (p less than 0.001) after endarterectomy. In 12 patients with significant bilateral occlusive carotid disease, mean +/- SD contralateral Doppler ophthalmic pressure index increased from 0.54 +/- 0.05 to 0.61 +/- 0.06 (p less than 0.02), whereas contralateral pressure index in patients with unilateral disease showed no change (0.71 vs 0.71) after ipsilateral endarterectomy. These results indicate that carotid endarterectomy not only normalizes ipsilateral Doppler ophthalmic pressure index but also improves contralateral Doppler ophthalmic pressure index provided significant bilateral occlusive carotid disease is present.