Contrast Sensitivity and Macular Degeneration
Guardion Health Sciences
Contrast sensitivity is a measure of visual function that distinguishes how an object is different from its background.
Good contrast sensitivity is important for your safety and well-being. It helps you drive at night by allowing you to see things like pedestrians on poorly lit streets. It also helps reduce your risk of tripping and falling when going down stairs or stepping off a curb. If you cannot distinguish the curb from the pavement or one step from another, you put yourself at risk of injury.
Macular Degeneration Causes Reduced Contrast Sensitivity
The deterioration of the macula (macular degeneration) leads to vision loss as well as a few other key visual changes. One such change is a reduction in contrast sensitivity. Often, a reduction in contrast sensitivity is the first sign of AMD-related vision loss.
The macula has the highest concentration of photoreceptors, or light-sensitive cells, in the retina. Some of these photoreceptors are classified as cones; located in the fovea (the central part of the macula), they are responsible for helping us see and distinguish colors.
As macular degeneration progresses and cone cells deteriorate and die, colors begin to look faded and not as brilliant as they used to be. The loss of the ability to see bright, vibrant colors is accompanied by the loss of contrast sensitivity. For example, objects that are navy blue and black may begin to look very similar; or it may be hard to see a white object like a car against the snow or find an object in a dark garage.
Consequently, testing the ability to see colors and distinguish contrast can be an important part of diagnosing macular degeneration. In fact, contrast sensitivity can play a part in detecting diseases like macular degeneration before other tests. It is also a way to measure visual improvements after starting treatment.
How Is Contrast Sensitivity Tested?
Testing contrast sensitivity takes place in an eye doctor’s office. Normally it isn’t included in a standard eye exam. Rather, it is recommended based on a specific visual complaint or based on the doctor’s suspicions that you might have a condition that affects your contrast sensitivity.
Testing contrast sensitivity involves the use of a VectorVision test, which is the only fully standardized test for contrast sensitivity. The test presents a series of bar patterns of different contrast levels to the patient. The doctor or testing technician identifies the lowest contrast level bar patterns detected by the patient to determine the patient’s contrast sensitivity. The VectorVision test can also be used in conjunction with glare testing. This test is widely used in FDA clinical trials and has standardized published population norms for different age groups. After you take the test, ask your doctor how well you did compared to other people in your same age group.
VectorVision CSV-1000 with Glare Test
Research Indicates Carotenoids Improve Contrast Sensitivity
We know that many patients with macular degeneration have a reduced macular pigment and reduced contrast sensitivity. Consequently, restoring and replenishing the macular pigment can help increase contrast sensitivity. Consuming enough carotenoids is an important part of building and maintaining a resilient macular pigment, but most people don’t get enough carotenoids in their daily diet.
Lumega-Z is the only medical food containing the three carotenoids that make up the macular pigment: lutein, zeaxanthin and meso-zeaxanthin. In studies, patients taking Lumega-Z showed improvements in contrast sensitivity in as little as two to three months.
Below is a typical contrast sensitivity curve for a patient, before and after nutritional therapy with Lumega-Z. Note that before treatment, the patients’ curves are below the gray shaded area, which means the patient’s contrast sensitivity is below the normal range and the patient cannot see the lower contrast levels patterns. Six months after treatment starts, the contrast sensitivity curves have improved upwards, so that now the patient has normal contrast sensitivity and can see much better at low contrast levels. Being able to see lower contrast level images is very important in everyday environments, like driving at night, walking over a dimly lit step or golfing in early morning haze.
Learn More about Lumega-Z
For more information about Lumega-Z’s unique formulation or to place an order using your doctor’s authorization code, please contact Guardion Health Sciences today.