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Article
February 1992

Blood-Retinal Barrier Breakdown Caused by Diode vs Argon Laser Endophotocoagulation

Arch Ophthalmol. 1992;110(2):277-281. doi:10.1001/archopht.1992.01080140133040
Abstract

• We compared the effects of argon and diode laser endophotocoagulation on blood-retinal barrier breakdown using real-time magnetic resonance imaging following intravenous gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) injection. Endophotocoagulation was performed on eyes of pigmented rabbits with either the argon or the diode laser to produce ophthalmoscopically similar lesions. Magnetic resonance imaging studies were performed either 2 or 7 days after laser treatment, and coronal T1weighted proton images were obtained in the first 20 minutes following Gd-DTPA injection. The mean signal intensity over a region of interest in the vitreous cavity was analyzed, and an initial rate analysis was performed on each time-course curve. Two days after treatment, argon laser—treated eyes showed significantly greater leakage of Gd-DTPA than diode laser—treated eyes. The leakage in both groups was substantially reduced by posttreatment day 7. Histopathologic examination performed 2 days following photocoagulation showed less damage of the retinal pigment epithelium and more severe occlusion of the choriocapillaris and deep choroidal vessels in diode laser—treated eyes. These changes may serve to explain the observed differences in Gd-DTPA leakage.

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