What is Low Vision?
Defining Low Vision Optometrists define low vision as a decrease in functional eyesight that makes completing everyday tasks difficult for those affected. Factors that cause low vision include genetic inheritance, aging, trauma, and exposure to harmful environmental conditions or lifestyle elements. Those with low vision experience varied levels of difficulty accomplishing activities such as reading, writing, driving, and recognizing shapes and objects.
What Causes Low Vision?
Vision loss occurs from a variety of causes. Some conditions are medical. Examples are macular degeneration, diabetic retinopathy, cataracts, and glaucoma. Some conditions are genetic. Examples include Stargardt’s Disease, Retinitis Pigmentosa, and albinism. Other causes can be congenital or traumatic.
Low Vision Doctors are more concerned with the amount of remaining vision, not the cause of the loss itself.
How is a Low Vision Exam Different?
A low vision examination is quite different from a regular eye examination. It is a longer examination usually lasting one hour or more. It is a “vision and function” examination; therefore medical tests such as dilation are usually omitted. The first part of the low vision examination is conversing with the patient to find out how the reduced vision is affecting their life. The “wish list” is created so the doctor understands what the patients’ goals are. The second part is extensive vision testing. Careful refraction is performed to find out if a new “regular” eyeglass prescription will help. Part three works with magnification, illumination and other optical and non-optical low vision devices. The doctor must determine the best form and level of magnification needed for the person to perform the desired tasks. Telescopes, microscopes, and prisms, with varying levels of magnification and strength as well as other magnification devices are presented to the patient. Illumination levels must be determined as lighting plays a major role in vision. Part four is another conversation with the patient to determine the best form and level of magnification for that particular person’s task requirements.