Glaucoma specialists take pictures of the optic nerve in order to measure damage to this important cable that connects your eye to your brain. There are several types of pictures, and each one provides different information about the amount of optic nerve tissue lost as well as the rate of nerve fiber thinning or "progression" that occurs when glaucoma is not controlled.
Viewing the optic nerve through lenses and a slit lamp is the best way for your doctor to assess the optic nerve for glaucoma. Your doctor may document this assessment either with drawings or with optic disc photos. A color photograph provides a more accurate baseline for future comparison. Photographs do not get outdated, and the information contained in them can be very useful for demonstrating "no change" years later.