Quantitative assessment of the optic nerve head with the laser tomographic scanner

Abstract

We describe the use of a laser tomographic scanner to objectively measure optic nerve head topography. A laser beam is focused on the optic disc using confocal imaging. Reflected light is detected only if it originates from a small region around the focal place of the special optics. Optic disc parameters are calculated from the measured values of confocal reflected light. In five glaucomatous eyes, maximum cup depth was between 0.33 mm and 0.58 mm. Cup volume was between 0.10 mm3 and 0.65 mm3; it correlated well with ophthalmoscopy. Compared with conventional imaging systems, the laser tomographic scanner has certain advantages: 1) images can be obtained with miotic pupils; 2) clarity of media is not important; 3) low light intensity is employed; and 4) a real time image is obtained.