A clouding of the natural lens of the eye is called a cataract. There are three types of age-related cataracts---nuclear, cortical and posterior subcapsular---that can develop as people get older, according to The Eye Digest. Each type of cataract develops in a specific portion of the lens. Cortical cataracts develop in the shell layer over the nucleus of the lens. The different types of cataracts have different symptoms; cortical cataracts cause symptoms such as decrease in vision, glare and double vision.
Vision Loss
The shell layer of the lens is called the cortex. The changes in cortical cataracts start as changes that look like spokes of a wheel at the edges of the lenses, according to the Mayo Clinic. When these changes are still mainly involving the edges, the visual acuity is not affected. However, when the number of lens changes start to increase, the visual acuity can start to decrease. The visual acuity typically does not decrease as much in cortical cataracts as with other types of cataracts; the cataract changes in the lens cortex cause other types of significant visual problems.
Glare
Opacities anywhere on the cortex of the lens can interfere with the light rays that are entering the eye, as noted on the Mayo Clinic website. This reflection of light can cause problems with glare for the person with the cortical cataract. These glare problems can also affect the person's ability to drive at night. This symptom may be significant enough to interfere with a patient's ability to function and may direct the person to have an eye examination.
Double Vision
Some people with cortical cataracts develop problems with double vision involving one eye, which is called monocular diplopia, as noted in the Digital Reference of Ophthalmology. When the opacities in the cortex of the lens are located in the visual axis---which is the center of the lens---the reflection of light that can result in glare can cause the person to see two images in one eye. This symptom may become disruptive and the patient may follow up with an eye doctor.
