Schirmer's test

Schirmer's test helps to diagnose symptoms of dry eye syndrome. It determines whether the eye produces enough tears to keep it moist. How it works:

1. anesthetic eye drops are applied to anaesthetize the eye surface so the tested subject feels no irritation in the eye
2. a strip of filter paper is placed in both lower eyelid pouches
3. the filter paper absorbs tears produced during a 5-minutes test period

The eyes of young, healthy people normally moistens 15 mm of each paper strip. If less than 15 mm of the paper is moistened, it can be due to aging or dehydration, corneal ulcers, eye infections, or vitamin A deficiency.