Effect of Laser Photocoagulation on the Retinal Vessel Diameter inBranch and Macular Vein Occlusion

OBJECTIVE To investigate the response of retinal vessel diameters to photocoagulationtreatment and their role for the success of laser treatment in patients withretinal vein occlusion. METHODS The study included 14 patients with branch vein occlusion or macularvein occlusion. The ophthalmologic examination included best-corrected visualacuity, biomicroscopy, fundus photography, and fluorescein angiography. Retinalvessel diameters were quantified before and after laser photocoagulation usinga retinal vessel analyzer. MAIN OUTCOME MEASURE Retinal vessel diameters. RESULTS In cases manifesting macular vein occlusions, no significant changeof the vessel diameter in any vessel was observed during the follow-up period.In the group with branch vein occlusion, all vessels tended to constrict afterthe laser photocoagulation. The effect of laser treatment on retinal vesseldiameters was significant for superotemporal (P =.045, analysis of variance [ANOVA]) and inferotemporal branch veins (P = .03, ANOVA). Vasoconstriction was more pronounced inthe occluded branch veins (P = .009, ANOVA) comparedwith the nonaffected veins (P = .12; ANOVA). Thechange of visual acuity after 3 months was correlated with the change of vesseldiameter 3 months after laser treatment for occluded venular branches (r = 0.78, P = .02, linear regression).There was no correlation between the number of laser burns and the changeof vessel diameters in the affected veins in this period (r = 0.12, P = .75, linear regression). CONCLUSIONS Our results show that retinal photocoagulation in patients with branchvein occlusion has a vasoconstrictive effect on occluded veins. The correlationbetween the change in visual acuity and the change in vessel diameter indicatesthat branch vein constriction after photocoagulation may be an early indicatorof the success of laser treatment.Arch Ophthalmol. 2004;122:987-991-->