Digital fundusphotography in equine ophthalmology

Fundusphotography for documentation of single cases of fundusabnormalities has become routine in equine ophthalmology though only conventional cameras has been used. In this study digital photography in the equine fundus was applied for the first time. This paper concentrated primarily on the clinical use, the abilities and limits of the system also compared to the conventional cameras up to now. Normal anatomy and variations, as well as some specific diseases of the fundus, could be presented. This study was comprised of 59 horses of various age, sex and breed and two donkey-mares. All of these equids were treated in the in the Equine Clinic of the Ludwig- Maximilians- University of Munich, Germany, from the 22. 4. 2004 to the 22. 11. 2004. The device for this application was the Scanning Digital Ophtholmoskop (R) of the Wild Medtech Company. The examination of nine horses was performed on standing animals. Fourtythree horses and one donkey were examined under general anesthesia, and seven horses and one donkey were examined post mortem. During the procedure the examiner was holding contact to the horse's head with one hand to prevent sudden movements or to react to them. Or he used the hand to hold the eyelids open. In the other hand he held the camera at the grip in a distance of several millimetres to the cornea. The photographs were taken as single pictures or snap shots out of a video. This way of imaging was very useful in the standing horse. Though it was a non-invasive method sedation was needed in all standing horses because of nervous behaviour. No adverse reactions resulting from the examination were observed throughout the course of this study. Due to its compactness and the easy handling the application of the camera is practical and suitable in equine ophthalmology. By changing the objectives the SDO is also able to take pictures of the anterior segment of the eye. In addition there is a sensitive black and white camera and a special filtersystem to perform a fluorescein angiography. There is the choice between real time video modus or single shots. Concerning sharpness and resolution digital fundus photography provides the examiner with images from healthy as well as pathological changed fundi of slightly less quality than conventional photography. Though after scanning the conventional photographs are loosing much of their resolution compared to the digital ones. However so for there is nothing equally good with regard to the naturalness and range of colours of conventional fundus photographs. Yet, in the age of multi media, the camera used in this study proves an appropriate application to document a pathologic finding in equine ophthalmology because of its easy handling and satisfying results.