Abstract
Purpose: :
To demonstrate a cost effective, portable, and user-friendly fundus imaging system for use with small animals.
Methods: :
A compact, contact GRIN lens (Rol et al, Optical Engineering, 1995) fundus imaging system (Paques et al, IOVS, 2007) was designed and constructed using standard optical and mechanical components; a digital camera, an otoscope, a fiber-optic light source, standard optical lenses, and mounts. Digital fundus video and photography of 2 albino rats, 2 pigmented mice, 2 albino Guinea Pigs, and 2 New Zealand white rabbits were obtained at BPEI. For all animals examined, pupils were dilated and local anesthetic (proparacaine hydrochloride 0.5%, Alcon Inc., Fort Worth, TX) and gel (Gonak, Akorn Lake Forest, IL) were administered. The instrument was transferred to the department of infectious diseases in Johns Hopkins and was used in a biological hood to image Guinea pigs with active Tuberculosis.
Results: :
No corneal epithelial damage occurred in any of the animals. Digital images of the fundus were obtained in all animals. Contrast of retinal vasculature and overall image quality varied from one species to another, since the axial length, ocular optics and retinal reflectance varied significantly across species. Light intensity and focus was easily optimized to produce high quality images for each animal. The optical system produces images of similar quality as those obtained with a standard fundus camera but does not produce the strong specular reflex associated with slit-lamp and ophthalmoscope-based instruments and in images produced using an operation microscope and contact lens.
Conclusions: :
The portable, cost-effective contact fundus imaging system is easy to use for examination of the eyes of small animals.Support: NIH P30EY14801 (Center Grant); the Florida Lions Eye Bank; an unrestricted grant from Research to Prevent Blindness and the Henri and Flore Lesieur Foundation (JMP)
Keywords: imaging/image analysis: non-clinical • retina • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)