Ophthalmoscopy

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How is the Test Performed?

Direct ophthalmoscopy: You will be seated in a darkened room. The examiner performs this common examination by projecting a beam of light from an ophthalmoscope, an instrument about the size of a flashlight, through the pupil to view the back of the eyeball.

The magnification obtained by using the direct ophthalmoscope occurs because the eye itself is a simple magnifier. The rotating lenses incorporated in the instrument are used to compensate for the refractive error of the examiner or the patient being examined.

Slit-lamp ophthalmoscopy: You will be seated at the same instrument used in examining the front part of the eye. An additional lens will be held close to the eye to enable the doctor to see the fundus. This has the advantage of a stereoscopic view in addition to the magnification of direct ophthalmoscopy. The view is much wider than that of direct ophthalmoscopy, but not as wide as indirect ophthalmoscopy.

Indirect ophthalmoscopy: You will either lie or sit in a semi-reclining position. The examiner performs this examination by holding the eye open. The examiner wears an instrument on the head resembling a miner's light. While holding the eye open and using a hand-held instrument, the examiner shines a very bright light into the eye. Some pressure may be applied to the eyeball using a small, blunt instrument, and you will be asked to look in various directions.

This examination takes between 5 and 10 minutes. The bright light will be uncomfortable, but the test is not painful. This examination requires more skill and time than the other forms of ophthalmoscopy, but has the advantage of allowing the doctor to see the entire retina.