• An exam is the best way to catch an eye problem.eye image by Pali A from Fotolia.com
  
  The human eye is part of a complex system that uses light to see an image, then transfers the image to the brain, where it is processed. Your eyes take microseconds to allow you to see automatically and clearly throughout your lifetime. Sometimes an injury or disease, like glaucoma or cataracts, may cause vision loss or even blindness if undetected. Routine eye exams are the best way to spot problems early to help preserve your vision.
  
  

General

• The most common eye exam is a general one that determines the eyes' health and how well you can see. The doctor will use a series of vision charts to check how the pupils react to light, and to determine perception of distance, color and depth. A refraction test checks for farsightedness, nearsightedness or astigmatism through a series of lenses the doctor puts in front of your eyes, then asks you to choose which view is better. The results help the doctor determine whether you need to wear glasses or contacts to correct a problem. The tests are painless, and it will not be necessary to dilate the pupils.
  
  

Glaucoma

• According to the Glaucoma Research Foundation, the at-risk groups for glaucoma include African-Americans, who are six to eight times more likely than Caucasians to contract it; and people 60 years of age and older, who are six times more likely. Glaucoma is a build-up of fluid that does not drain normally away from the eye, which clogs the optic nerve, creating pressure. An intraocular pressure test blows a puff of air against the eye to measure its reaction. The doctor uses drops to dilate the pupils, then examines the optic nerve with an ophthalmoscope for fluid build-up. A vision field test evaluates your peripheral or side-to-side vision. Diabetics are in the high-risk category for glaucoma.
  
  

Cataract

• A cataract consists of groups of protein particles that come together, affecting the eye's lens. These groups eventually cause cloudiness that creates blurred vision. It is more common in older people. The National Eye Institute states that 50 percent of 80-year-old Americans have had a cataract or cataract surgery. People most at risk are diabetics, smokers, drinkers, and sun-worshipers. During the test, the doctor dilates the pupils to examine the retina, optic nerve and inner eye. A slit lamp projects a slim, bright light beam that gives the doctor a magnified 3-D look at your eye for protein groups. Warning signs of a cataract may include blurry vision, faded colors, bad night vision or a halo effect around headlights or lamps.