The New York University Langone Medical Center, on the other hand, reports no marked increase in blood sugar levels in diabetics. As a precaution, however, you should discuss fish oil supplements with your health care provider, if you have diabetes. If you're already taking fish oil supplements, keep a close watch on how your blood sugar levels vary.
Another condition that can cause headache above left eye is glaucoma. This condition is due to the build-up of pressure within the left eye that causes damage to the optic nerve, destroying peripheral vision and leading to blindness. Any infections or tumor in the left eye or brain can cause pain around the eye.
The potential causes of vision changes with eye pain and/or head pain are numerous. Certain headache disorders such as migraine can cause vision changes followed by headache. If you are older than the age of 55, one potential cause of headache with vision changes is called giant cell arteritis or temporal arteritis.