What is a cortical cataract?
A cortical cataract is an opacity in the outer layer, or cortex, of the natural lens. It is more common in people with diabetes and hypertension. Symptoms of cortical cataracts include glare, blurred vision and a decreased ability to perceive color, contrast and depth.
According to the Beaver Dam Eye Study, the incidence of cortical cataracts is around 1 in 10 for people between 43-86 years old. It is a widespread age-related condition and becomes more common as we get older.
What causes cortical cataracts?
A cortical cataract is caused by the buildup of protein fibers in the outer layer (cortex) of the lens. These clusters of clumped proteins disrupt the transparency of the lens fibers, resulting in opacities in the lens.
Opacities that form in the lens cortex develop a (wheel) spoke-like appearance. These opacities are very effective at scattering light as it passes through the lens to the retina. This is why glare and light sensitivity are common early symptoms of cortical cataracts.
As the cataract progresses, the spokes grow into the center of the lens. As this happens, blur increases, color vision becomes altered and depth perception worsens.
Conflicting research has associated cortical cataract with high myopia as well as hyperopia. The most common cause of cortical cataracts, however, is increasing age.
Additional factors that can increase your risk of cortical cataracts include:
Medical conditions such as diabetes and hypertension
Smoking and tobacco use
Excessive exposure to UV radiation, especially UV-B
Poor diet, especially one lacking in carotenoids (nutrients found in richly colored fruits and vegetables such as tomatoes, carrots, peppers and spinach)
