One of the most important finding during the course of a comprehensive vision examination is the visual field. This is where we measure the patient’s peripheral vision, one eye at a time. The information from the visual fields could indicate eye disease such as glaucoma or even detached retina. More importantly, it could give us information regarding possible tumors or aneurysms within the brain. I actually had a patient who complained of headaches and blurred vision when she came in. Her visual fields showed a defect in each eye. The patient happened to have an aneurysm in the brain. It actually ruptured during the operation. The surgeon was able to save her life even though the patient lost vision in one of her eyes. If the finding of the visual field defect went undetected and the surgery didn’t occur when it did, the patient would have very likely died.