Fluorescein angiography of the canine posterior segment using a dSLR camera adaptor

To describe the use of a digital single lens reflex (dSLR) camera adaptor for conducting posterior segment fluorescein angiography in canines.

Ten beagle dogs free of ocular and systemic disease were used. All dogs received maropitant citrate (1.0 mg/kg SQ), diphenhydramine (2.0 mg/kg SQ), and topical 1% tropicamide 20 min prior to sedation using butorphanol (0.2 mg/kg IV). Standard color and red-free fundus images were obtained prior to the 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 60 mm macro), and a 60D indirect ophthalmic lens, in addition to an accessory flash (Canon 580EXII). Two combinations of excitation and barrier filters were assessed (absorptive vs. interference). Imaging occurred at a rate of 1/s immediately following the fluorescein bolus for a total of 30 s and then at 1, 2, 3, 4, and 5 min.

Quality high resolution fluorescein angiographic images of the canine posterior segment were obtainable. All angiographic phases were identified and time sequences were recorded. Use of interference filters improved image contrast and transmission properties as compared to absorptive filters. No adverse events were noted.

The described dSLR camera adaptor provides an alternative to existing posterior segment imaging systems capable of performing fluorescein angiography. High resolution image acquisition occurred at a fraction of the cost of established imaging systems.