An ophthalmoscopy is the examination of the internal eye. A dilated retinal exam allows for an even more thorough evaluation of the internal eye. Examination of the inner eye is necessary to evaluate the optic nerve head.

Glaucoma affects the optic nerve head causing cupping and nerve cell fibers are destroyed. This destruction of healthy nerve fiber cells at the optic nerve causes loss of the peripheral visual field. This cupping is the hallmark sign of glaucoma. The amount of cupping should remain stable throughout life. If the cupping is gradually getting larger over time, glaucoma could be developing, thus a yearly dilated retinal examination to monitor cupping of the optic nerve head is important in the early detection of glaucoma.

The optic nerve head is evaluated by many techniques. Two common methods are (1) with a retinal slit lamp and (2) with a binocular indirect ophthalmoscope. Both of these procedures allow the doctor to view your magnified optic nerve as it reaches the back of the eye from your brain. This allows an accurate cup-to-disc ratio to be made.

A cup-to-disc ratio is critical when evaluating glaucoma. The cup-to-disc ratio is the amount of the entire nerve head that has been cupped out or where glaucoma has caused damage. Readings range from 0 meaning no cupping at all to 1.0 where the entire optic nerve is cupped out. Many people have some cupping--which is normal. Changes in size of the cup-to-disc ratios or a difference between the two eyes lead the eye care specialist to suspect glaucoma. The cupping of the optic nerve head is directly related to the loss of one's peripheral visual field.

The IU School of Optometry Ocular Disease Service strives to maintain the latest technology for diagnosing and managing glaucoma. The facility is equipped with two retinal cameras to provide accurate photographic documentation of the appearance of patients' optic nerve heads. Our stereo disc camera allows us to take three dimensional pictures of the nerve head for comparison at later appointment dates.

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	URL: http://www.opt.indiana.edu/clinics/pteduc/glaucoma/ophthal.htm Revised: August 2, 2002
	IU Optometry home page: http://www.opt.indiana.edu/ Comments: Web Administrator Page design and coding: Terri Greene Copyright © 2002, The Trustees of Indiana University