Having trouble viewing pupil response to light in patients with brown eyes? In dark room conditions, the lack of contrast between a dark iris and the pupil can make it difficult to appreciate changes in pupil size.

Try this technique (this takes two hands): use the rheostat on your ophthalmoscope to dim its light. In your other hand, hold a much brighter light source (another scope, flashlight, smart phone, etc). You will first focus the dimmer light on or near the pupil; adjust the brightness so you can easily see the pupil but so it is dim enough to induce minimal pupillary response.

Swing the bright light onto the pupil. You’ll be able to see even subtle changes. Practice on yourself in the mirror or on volunteers (family or friends). You should be able to easily find the right combination of brightness setting and positioning. — ROBERT KOORSE, MD, Hartford, Conn. (199-3)

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