CONJUNCTIVITIS is most of the time innocent, IRITIS not.[needs an opthalmologist]
For the first time, I read about this test and maybe most doctors know about it, I did not. We learned other ways to distinguish between conjunctivitis and Iritis, but this seems a very simple elegant test. As the right diagnosis can save the eye I found it important to send this mail and I realize that patients can even perform this test at home on the instruction of the doctor in case of doubt.
When in doubt about the distinction between iritis and conjunctivitis, proceed to the Au–Henkind test (Au and Henkind, 1981).
Ask the patient to close the eye to be tested, leaving the other eye open. Shine a penlight into the open eye and ask the patient whether he has experienced a sensation [pain] in the closed eye.
Pain in the closed eye is a positive test for iritis. This test presumes that a normal consensual pupillary response response to light is present. The test is 100% sensitive and highly specific.
Orient, Jane M.. Sapira’s Art and Science of Bedside Diagnosis . Lippincot (Wolters Kluwer Health). Kindle Edition.