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OCULAR BLOOD FLOW VELOCITIES IN PATIENTS WITH PROLIFERATIVE DIABETIC RETINOPATHY AFTER SCATTER PHOTOCOAGULATION: Two Years of Follow-Up

Purpose: Color Doppler imaging allows for simultaneous two-dimensional anatomic 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 after, 1 year after, and 2 years after panretinal photocoagulation with a matched control group of 30 healthy volunteers (55 eyes). Methods: The ophthalmic artery, short posterior ciliary artery, central retinal vessels, and vortex veins of all patients were examined, and the systolic, end diastolic, and mean arterial velocities were measured. Panretinal photocoagulation was performed with these parameters: 800-1000 spots, 0.1 second, 500-μm argon laser. Results: Student's f test revealed that the perfusion velocity was significantly lower in diabetic patients than in healthy controls (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; 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 patient age and blood velocities in diabetics and healthy volunteers. Conclusions: Eyes with proliferative diabetic retinopathy showed lower ocular perfusion velocities than controls. Photocoagulation resulted in a reduction in ocular blood flow velocities; these values did not change during 2 years of follow-up.