A portable, contact animal fundus imaging system based on Rol's GRIN lenses.

Objective: To demonstrate a cost-effective, portable, and simple-to-use fundus imaging system for laboratory animals.

Animals Studied: Albino rats, pigmented mice, albino guinea pigs, and New Zealand white rabbits.

Procedure: A contact fundus imaging system was designed and constructed using standard optical and mechanical components: a digital camera, an otoscope, a fiber optic light source, and standard optical lenses and mounts. Digital fundus video and photography of two albino rats, two pigmented mice, two New Zealand white rabbits, and two albino guinea pigs were obtained. For all animals examined, pupils were dilated and local anesthetic was administered.

Results: Digital images of the fundus were obtained in all animals. Contrast of retinal vasculature and overall image quality varied from one species to another, as the axial length, ocular optics, and retinal reflectance varied significantly across species. Light intensity and focus were optimized via the light source and lens focusing mount to produce high-quality images for each animal.

Conclusions: The portable, cost-effective contact fundus imaging system was easy to use for fundus examination of laboratory animals.