HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Arnarsson, A. Articles by Stefánsson, E. Search for Related Content PubMed PubMed Citation Articles by Arnarsson, A. Articles by Stefánsson, E.

Laser Treatment and the Mechanism of Edema Reduction in Branch Retinal Vein Occlusion

¹ From the Department of Ophthalmology, University of Iceland, Reykjavik, Iceland.

PURPOSE. To test a hypothesis on the physiological mechanism of the disappearance of macular edema after laser treatment. The hypothesis is based on the effect grid laser treatment has on retinal oxygenation and hemodynamics. It predicts that laser-induced reduction of macular edema is associated with shortening and narrowing of retinal vessels in patients with branch retinal vein occlusion (BRVO).

METHODS. The study included 12 subjects, treated with argon laser photocoagulation for BRVO and macular edema. Fundus photographs taken at the time of diagnosis and again after laser treatment, were digitized, and diameter and segment length of retinal vessels was measured using NIH-Image program.

RESULTS. Macular edema disappeared or was dramatically reduced in all cases after laser treatment. The diameter of occluded venules constricted to 0.81 ± 0.02 (mean ± SD, P = 0.019) of the prelaser diameter and adjacent arterioles constricted to 0.78 ± 0.01 (P = 0.008). The laser treatment also led to shortening of the affected vessels. The final segment length of the occluded venules was 0.95 ± 0.17 (P = 0.005) of the length before treatment. The corresponding value for the adjacent arterioles is 0.95 ± 0.14 (P = 0.008). Control arterioles and venules in the same fundus did not change in either length or width.

CONCLUSIONS. These results do not reject the authors’ hypothesis that the disappearance of macular edema in BRVO can be explained by the effect the laser photocoagulation has on retinal oxygenation. Increased oxygenation causes vessel constriction and shortening and lower intravascular pressure, which reduces edema formation according to Starling’s law.

This article has been cited by other articles:

				M. Ota, A. Tsujikawa, T. Murakami, M. Kita, K. Miyamoto, A. Sakamoto, N. Yamaike, and N. Yoshimura Association between integrity of foveal photoreceptor layer and visual acuity in branch retinal vein occlusion Br. J. Ophthalmol., December 1, 2007; 91(12): 1644 - 1649. [Abstract] [Full Text] [PDF]

				A. Polito, G. Polini, R. G. Chiodini, M. Isola, F. Soldano, and F. Bandello Effect of Posture on the Diurnal Variation in Clinically Significant Diabetic Macular Edema Invest. Ophthalmol. Vis. Sci., July 1, 2007; 48(7): 3318 - 3323. [Abstract] [Full Text] [PDF]

				Writing Committee for the Diabetic Retinopathy Cli Comparison of the Modified Early Treatment Diabetic Retinopathy Study and Mild Macular Grid Laser Photocoagulation Strategies for Diabetic Macular Edema Arch Ophthalmol, April 1, 2007; 125(4): 469 - 480. [Abstract] [Full Text] [PDF]

				D.-Y. Yu, S. J. Cringle, E. Su, P. K. Yu, M. S. Humayun, and G. Dorin Laser-Induced Changes in Intraretinal Oxygen Distribution in Pigmented Rabbits Invest. Ophthalmol. Vis. Sci., March 1, 2005; 46(3): 988 - 999. [Abstract] [Full Text] [PDF]

				N. Maar, A. Luksch, A. Graebe, E. Ergun, B. Wimpissinger, M. Tittl, P. Vecsei, M. Stur, and L. Schmetterer Effect of Laser Photocoagulation on the Retinal Vessel Diameter in Branch and Macular Vein Occlusion Arch Ophthalmol, July 1, 2004; 122(7): 987 - 991. [Abstract] [Full Text] [PDF]