Abstract
Purpose: :
Imaging eye structures had become an essential step in the diagnostic and follow up of retinal diseases or lesions in humans and animals. For instance, imaging the fundus in vivo in experimental models of retinal diseases is of great interest for screening purposes, for characterization of the natural history of retinal diseases or for monitoring therapeutic effects. We developed a simple and low-cost technique which allowed visualisation of many structures of the eye on many animal species.
Methods: :
Our device uses a human nasal telescope which the view is straight ahead from the tip of the instrument. The examiner can look directly through the telescope. Alternatively, a medical video camera can be attached. The examination may be recorded on a VCR or a digital image archive like a digital camera. For corneal protection and optic improvement, corneal gel was applied between the tip of the endoscope and the animal eye. Eye structures were examined on conscious rats, sedated dogs and cats, or anaesthetized monkeys and sheep. Images of angiography were obtained on rats. Only two persons were needed for the manipulation of the animals and device to generate digital images.
Results: :
The technique allowed quick and easy visualisation of eye fundus, ciliary bodies, iris, irido-corneal angle on a single eye examination without additional optical equipment. The fovea was clearly visible in primates while areas with decreased pigmentation in the retinal pigment epithelium could be detected at the eye fundus. Images of angiofluorography could be obtained with arterio-filling times. The technique allowed archiving of images with high resolution photo cameras or video cameras. The lens did not impair the visualisation of all these structures. No light toxicity was noted. The images qualities were superior at those obtained by the indirect ophthalmoscope, the current gold standard of the animals’ eyes imaging.
Conclusions: :
These results demonstrate the possibility of a simple and low-cost technique for visualisation of many eye structures of different species. In association with standard techniques, our device could become an elective technique for lab studies all at once for toxicity and screening studies. It may also apply to humans especially in underdevelopped countries or when the setting at a biomicroscope is impossible.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • anterior chamber