| Movement to popularize contrast sensitivity tests | | | | letter chart with solid black letters on an empty |
| happening now | | | | white background. Threshold contrast levels, such |
| A routine eye exam generally includes a screening | | | | as those measured with the Pelli-Robson chart, |
| for glaucoma, macular degeneration and a | | | | are also not very common. |
| standard visual acuity test on a high-contrast | | | | Dr. Colenbrander supports more studies and |
| letter-reading chart. While these eye health tests | | | | believes better - and quicker - low contrast |
| are clearly important to assess possible causes of | | | | sensitivity tests can be done using low-contrast |
| eye problems, they don't capture the "big picture", | | | | eye charts and mixed-contrast eye charts. These |
| which includes the functional consequences of eye | | | | cards present contrast levels that are more |
| problems; contrast sensitivity tests should be | | | | common in everyday tasks. The mixed-contrast |
| included to detect problems that affect functional | | | | eye charts, which he pioneered, have high- and |
| vision. | | | | low-contrast words, letters and objects side by |
| As the population ages, various age-related | | | | side. Dr. Colenbrander's reasons for developing the |
| disorders may decrease contrast sensitivity. This | | | | mixed-contrast format were two-fold: time and |
| will affect how people can use their vision in | | | | convenience. It is considered the fastest and |
| Activities of Daily Living. Detecting obstacles in | | | | most demonstrative way to explain low contrast |
| night driving, detecting the height of a curb (and | | | | sensitivity to patients and their families. |
| avoiding a fall and possibly a broken hip), detecting | | | | The doctor adds that once low contrast |
| milk in a Styrofoam cup, are all activities that | | | | sensitivity loss is diagnosed, clinicians can help |
| require adequate contrast vision. | | | | patients function better by offering them a |
| Clinicians are generally most interested in knowing | | | | tangible solution, such as a reading lamp or a |
| what causes a condition versus knowing the | | | | magnifier with increased illumination using LED |
| consequences of a condition for functional vision. | | | | lights. Dr. Colenbrander also warns patients with |
| This is why low contrast tests aren't normally | | | | low contrast sensitivity not to drive at night. For |
| included in a routine exam. If a patient cannot see | | | | example, if a pedestrian crosses the road in front |
| well enough, an ophthalmologist's first reaction is | | | | of a patient driving with low contrast sensitivity, |
| to find out what causes the condition. While this is | | | | the driver probably won't see the pedestrian since |
| necessary for effective treatment, it is often not | | | | it's a dark-against-dark scene with very little |
| enough to help alleviate the consequences for | | | | contrast. |
| functional vision. | | | | In the gadget-oriented society in which we live, |
| According to August Colenbrander, M.D., an | | | | consumers often think that we need a gadget to |
| affiliate senior scientist at the San Francisco-based | | | | alleviate the consequences of a problem. In many |
| Smith-Kettlewell Eye Research Institute, low | | | | situations, the awareness of the problem is just |
| contrast vision screening needs to be promoted, | | | | as good as any gadget. If an elderly patient does |
| since high contrast visual acuity tests are only a | | | | not understand her contrast problem, she may |
| partial predictor of how well people's vision will | | | | stumble over a low-contrast curb and break a hip. |
| serve them in Activities of Daily Living (ADL). | | | | If we can warn her, she will be more careful; so |
| Most such activities provide less contrast than a | | | | that this does not need to happen. |