Dr. Gary Morgan goes beyond normal testing. Did you know that 20/20 vision is not the same for all people? Contrast Sensitivity is a measure of one’s ability to see a target against its background. This can also be referred to as ‘faintness appreciation.’ Imagine driving directly into the sun at dusk when a child steps into the road. Now, the child is much larger than a 20/20 letter on an eye chart, but individuals will vary greatly in their ability to see the child (the target) against the glaring sun (the background). One’s Contrast Sensitivity in this case could be the difference in avoidance versus tragedy.
Related to Contrast Sensitivity is one’s ability to tolerate Glare. Glare occurs when an individual is exposed to a light source, either direct or indirect, that is in excess of their adaptive state. Such light exposure can cause discomfort, disability, or both. Discomfort Glare diminishes visual performance, we can still see, just not as well. The discomfort is made worse by short wavelength / high energy light, also known as blue light. Sunlight is predominantly blue, which is why the sky is blue. So, sunlight exposure, especially when the sun is low on the horizon as at dusk or dawn will increase our discomfort. Newer high-intensity automobile headlights that appear blue can also cause Discomfort Glare.
Disability Glare occurs from reduction of contrast; one can no longer tell a visual target from its background. It can occur directly as when driving into the sun or oncoming headlights. Disability Glare can also occur indirectly, as in when our eyes are exposed to a sudden bright light or flash. This bleaches the photopigment in our retina, causing photostress, and wiping out our contrast.
All patients receiving a vision exam at Triton Eye Care will have their Contrast Sensitivity and Glare tested. For those that don’t test up to par, specific recommendations will be made to improve their Contrast Sensitivity and Glare tolerance. For those interested in complying with recommendations, periodic follow-up testing will be performed to track improvements.
