Do You Have Visual Contrast Sensitivity?

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Acing the normal eye test with a 20/20 score — “perfect vision” — doesn't give you a true or complete assessment of how well you can see in the real world. Identifying those rows of black

letters on the white background lets your eye doctor measure your visual acuity. “It's basically how small are the letters that you can see on the eye chart,” explains John Hovanesian, M.D.,

clinical spokesperson for the American Academy of Ophthalmology (AAO) and professor at UCLA. He adds, “What that type of measurement does not include is shades of gray.” So, even with a

“perfect” visual acuity score, you may find that under specific environmental conditions, you can't accurately distinguish objects from their background.

This inability is called a lack of visual contrast sensitivity, which is usually not measured during your routine eye exam.

It's an extremely common condition associated with aging — about half of people 50 and older have it — and relatively harmless when it's mild. But sometimes vision quality can become poor

enough to result in falls or car accidents. It can also be a sign of an underlying condition, such as glaucoma and diabetes, which can result in blindness. (To check for glaucoma and

diabetes, AAO recommends a complete eye exam at age 40, and an annual eye exam for those 65 and older.)

You probably won't notice any symptoms of reduced contrast sensitivity at first, says Thomas Steinemann, M.D., AAO spokesperson and professor at MetroHealth Medical Center, because it

happens so incrementally. Sometimes, he says, “It is not obvious or apparent until pointed out.”

But you may notice some early signs when you have difficulty with: