Often, the healthcare provider will put special eye drops into the eyes that cause the pupils to open wider, or dilate. When the pupils are wide open, the provider can get a better view of the inside of the eyes with a special instrument called an ophthalmoscope. The pressure inside the eyeball can be measured to test for glaucoma. After the eyeballs have been examined, the person is then asked to read a standard eye chart to determine how well the person can see or to check the visual acuity. Other tests may also be needed in some cases.
Visual impairment can limit a person's ability to work, go to school, and drive.
Severely affected people may need special devices to help them with everyday activities. Other long-term effects depend on the cause. For example, glaucoma may lead to permanent loss of vision. Cases of nearsightedness or farsightedness often improve with the use of glasses or contacts. A stroke may cause permanent vision problems and other limitations from brain damage.