[Color Doppler echography study of ocular blood flow velocity in patients with proliferative diabetic retinopathy after performance of retinal pan-photocoagulation: 2 years' follow-up].

Purpose: Color Doppler imaging allows for simultaneous two-dimensional anatomical imaging and Doppler measurement of blood flow velocity. Because hemodynamic changes have been seen in diabetic patients after photocoagulation by other techniques, the authors compared 25 eyes with proliferative diabetic retinopathy before, 6 months, 1 year, and 2 years after panretinal photocoagulation with a matched control group of 30 healthy volunteers.

Methods: The ophthalmic artery, short posterior ciliary artery, central retinal vessels and vortex veins of all patients were examined, and the systolic, diastolic and mean arterial velocities were measured. Panretinal photocoagulation was performed with these parameters: 800-1000 spots, 0.1s, 500 micron argon laser.

Results: Student's t test revealed that the perfusion velocity was significantly lower in diabetic patients than in normals (Vsystolic in the ophthalmic artery: 31.7 (6.7) cm/s vs 36.6 (7.0) cm/s, respectively, P = 0.03). After treatment, blood flow velocities were significantly lower than before photocoagulation (Vsystolic in the ophthalmic artery: 6 months after treatment 26.9 (7.2) cm/s, P = 0.018 and 1 year after photocoagulation 25.5 (7.0) cm/s, P = 0.009; and 2 years after photocoagulation, 25.7 (6.8) cm/s, P = 0.01). No statistically significant differences were found between 6 months, 1 year, and 2 years after panretinal photocoagulation. No significant correlations were found between age and blood velocities in diabetics and healthy volunteers.

Conclusions: Eyes with proliferative diabetic retinopathy showed lower ocular perfusion velocities than normals. Photocoagulation resulted in a reduction in ocular blood flow velocities; these values did not change during 2 years of follow-up.