Showing papers on "Aerial image published in 1970"

Method and apparatus for measuring retinal depressions and elevations

Abstract: Retinal depression and elevation measurements are obtained with an apparatus which includes a relay lens which is placed in front of a subject''s eye to form an aerial image of the area of the retina of the eye to be measured. A marker having a needle point is placed on the opposite side of the lens from the eye. The aerial image is then viewed through a stereoscopic indirect ophthalmoscope, focusing first on a reference plane, the marker needle is moved into focus in the aerial image and then the ophthalmoscope refocuses onto a secondary plane in the image. By moving the marker needle into focus in the secondary plane, the distance of movement of the marker needle determines the relative depression or elevation of the secondary plane.