Retinal entoptic phenomena have been used for many years in studies of retinal physiology. Many of these phenomena can be of diagnostic value, particularly in cases where adequate ophthalmoscopic examination is difficult due to medial opacities. This paper will review some of the retinal entoptic phenomena and consider some of the diagnostic uses to which they have been put. The phenomena to be considered are as follows:
Maxwell's spot
Loewe's ring
Weekers' sign
Perimacular capillary circulation
Purkinje vascular figure
Haidinger's brushes
After-images
Phosphenes
Blue arcs of the retina
Moore's lightning streaks
Nebel's phosphene of quick eye movement
Self light of the eye
Macular shagreen
Maxwell's Spot is seen as a tiny dark centeral area, surrounded by a lighter ring which is in turn surrounded by a dark halo. The spot may be produced by looking first through a neutral or yellow filter at a white light and then looking through