Uncovering Contrast Loss With Your History
Thomas I. Porter, OD
Contrast sensitivity loss is common in most eye pathologies and congenital eye problems. Loss of contrast sensitivity is almost always accompanied by an increase in glare sensitivity. There are many good clinical tests that may be used to document the amount of contrast loss but a few simple questions in your history can streamline your approach to solving these contrast problems.
What follows is a series of questions and a short discussion that I have found very helpful in my clinical practice. Begin by asking your patient, “Does glare outside or inside bother you?” “Outdoors do you find cupping your hands around your eyes helps control the glare?” “When you wear sunglasses do they seem too dark at times?” “Do you find yourself putting them on and taking them off in various lighting conditions?”
From the answers I begin a short counseling and education discussion that paves the way to including glare and contrast enhancement in my treatment plan. I first describe contrast loss as in inability to visually separate the object one is looking at from the background. Next I educate my patient’s that in most eye problems contrast loss is very common and that is often accompanied by increased glare sensitivity. Patients are usually surprised to learn that standard gray and green sunglasses further reduce contrast sensitivity. This helps explain why these lens colors will often seem too dark or the patient reports constantly putting on and removing sunglasses. This is also the reason many patients have many pairs of sunglasses but none seem to be the “right shade”.
I point out that by using a lens in the yellow, orange, or dark amber range we can reduce the discomfort of glare like their current sunglasses while increasing contrast appreciation. This in turn will improve comfort and mobility. I have found that the most common reason patients reject contrast enhancing lenses is due to the initial shift in color perception. However if the patient is warned prior to putting on the filters most accept and adjust to these tints quite well.
By incorporating these history questions into your exam routine you will improve your prescribing success rate with this valuable category of low vision aid.