What is a severe headache behind the left eye? A severe headache behind the left eye may result from serious conditions, such as a brain aneurysm, that require emergency medical care. Other ...

It is a progressive disease affecting the optic nerve behind the eye. Glaucoma causes intense eye pain and a gradual loss of peripheral (side) vision. If left untreated, it can cause blindness.

Table 1. Causes of Headache and Third-Order Horner's Syndrome Dr. Jurkunas is affiliated with the department of cornea and external disease, Massachusetts Eye and Ear Infirmary, Boston ...