Anterior segment fluorescein angiography of the normal canine eye using a dSLR camera adaptor

To describe anterior segment fluorescein angiography (ASFA) of the normal canine eye using two different sedation/anesthetic protocols and a digital single lens-reflex (dSLR) camera adaptor.

Dogs free of ocular and systemic disease were used for this study. Dogs received maropitant citrate (1.0 mg/kg SQ) and diphenhydramine (2.0mg/kg SQ) 20min prior to butorphanol [n = 6] (0.2 mg/kg IV) or propofol [n=6] (4 mg/kg IV bolus, 0.2 mg/kg/min CRI). Standard color and red-free images were obtained prior to administration of 10% sodium fluorescein (20 mg/kg IV). Image acquisition was performed using a dSLR camera (Canon 7D), dSLR camera adaptor, camera lens (Canon EF-S 60 mm f/2.8 macro), and an accessory flash (Canon 580EXII). Imaging occurred at a rate of 1/s immediately following bolus for a total of 30 s, then at 1, 2, 3, 4, 5, and 10 min.

Twelve dogs with a combined mean age of 5.1 years and various iris colors were imaged. Arterial, capillary, and venous phases were identified and time sequences recorded. Visibility of the vascular pattern was inversely related to iris pigmentation. Complete masking of blood flow was noted with heavily pigmented irises. Vessel leakage was noted in some eyes. Proper patient positioning and restricted ocular movements were critical in acquiring quality images. No adverse events were noted.

This study demonstrated that quality high resolution ASFA images were obtainable using a novel dSLR camera adaptor. ASFA of the normal canine eye is limited to irises, which are moderately to poorly pigmented. Use of general anesthesia produced higher quality images and is recommended for ASFA in the dog.