It is often the source of much chagrin to both patient and operator when, following the removal of a cataract from an eye which had apparently projected light perfectly, a great defect is discovered in the macular region. The patient has had his hope of useful vision abruptly shattered, and the operator feels cheated out of the rewards of a trying and hazardous venture. Unfortunately, a history of previous visual acuity from the patient is not always reliable, and the projection test as ordinarily practiced does not reveal central retinal changes. The means of producing a very feeble illumination for testing macular perception are not always available.
While experimenting with entoptic phenomena, it occurred to me that the subjective visualization of one's own retina might be employed in detecting central lesions or central amblyopia. The method is well known. One removes the head from the electric ophthalmoscope and places