Purpose:
To describe a digital single lens reflex (dSLR) camera adaptor for posterior segment photography.
Methods:
The adapter was used to evaluate the fundus of normal canine and feline patients presenting to Tufts Cummings School of Veterinary Medicine. The adaptor mounts between a digital camera body (Canon Rebel xTi) and a macro lens (Canon EF-S 60mm/f2.8). Posterior segment viewing and imaging is performed with the aid of an indirect ophthalmic lens. Coaxial illumination for viewing is provided by a single white light emitting diode within the adaptor, while illumination during exposure is provided by the pop-up flash or an accessory flash. Exposure is controlled by through the lens (TTL) metering. Corneal and/or lens reflections are reduced using a pair of linear polarizers, having their azimuths at right angles to one another.
Results:
This pilot study demonstrated that quality high-resolution, reflection free, digital images of the retina could be readily obtained. Image acquisition occurred at a fraction of the cost of established digital fundus camera systems and required no additional software. A wide range of magnification(s) and/or field of view(s) were easily obtained by altering the indirect lens utilized.
Conclusions:
The described camera adaptor provides an alternative to existing fundic camera systems. Images obtained were of similar quality, however, the adapter proved to be more versatile, portable and of lower cost. Furthermore, it is not limited to one particular brand or model of dSLR. Its compact size and light weight allows for easy handling, in addition to, transportation to remote locations.
Keywords: imaging/image analysis: clinical • retina