Research of wide-area retinal imaging technique

In view of the traditional fundus camera which can not check the defects of retinal edge, a non-mydriatic wide-area retinal imaging system based on Volk contact lens is proposed.In sufficient lighting conditions, Volk lens can reach more than 130° field of view(FOV).The illumination way is improved based on traditional fundus camera, and by the way of using external annular fiber illumination, the retinal wide-area illumination is realized. The incident angle is increased to eliminate the influence of ghost image, and the dark spot phenomenon in center region can be avoided which is caused by annular lighting meanwhile.The objective lens group eliminates the stray light caused by the corneal reflex and uses the manual focusing method to make a clear image on the complementary metal-oxide semiconductor (CMOS) camera.The fundus images are collected by the colorized CMOS camera with (2/3)′ image acquisition board and then uploaded to the PC terminal in real-time for analyzing, processing, archiving and other operations.Images after post-processing can provide clear, objective bases for the diagnosis and screening of varied kinds of eye diseases.