There are three cataract types, each defined by their location on the lens.
- Nuclear cataracts are found in the center, or nucleus of the lens.
- Cortical cataracts begin at the outer rim of the lens, which is known as the cortex, and work toward the center.
- Subcapsular cataracts affect the back of the lens in the capsule, or the membrane that envelops the lens.
Because each of these cataract types affects vision in a distinct manner, it is possible for a patient to have more than one type of cataract at the same time. While age is the most common risk factor for cataracts, some cataract types may also be attributed to:
- Eye trauma
- Certain prescription drugs or steroids
An experienced ophthalmologist can diagnose each of the different cataract types and discuss treatment options. In the majority of cases, patients choose to undergo cataract surgery in order to reduce symptoms such as cloudy vision.
Nuclear cataracts, which form in the lens' nucleus, are the most common type of cataracts. Because opacity develops in the center of the lens, known as the central nucleus, nuclear cataracts interfere with a person's ability to see objects in the distance. Usually the result of advancing age, nuclear cataracts can take years to develop and often give the nucleus a yellow tint.
Cortical cataracts begin at the outer rim of the lens and gradually work toward the central core of the lens. This type of cataract resembles spokes of a wheel that extend from the outside of the lens to the center. Patients with cortical cataracts often notice problems with glare, or a "halo" effect around lights, and experience a disruption of both near and distance vision.
Of all cataract types, subcapsular cataracts progress the most rapidly. While nuclear cataracts take years to develop, subcapsular cataracts reach an advanced stage of progression within a matter of months. Posterior subcapsular cataracts affect the back of the lens, causing glare and blurriness. This type of cataract is usually seen in patients who suffer from diabetes, extreme nearsightedness or retinitus pigmentosa, or who take steroid medication.
Congenital cataracts refer to cataracts that are present from birth, or are developed in early childhood, and may include nuclear, cortical or subcapsular cataracts.Congenital cataracts may be linked to an infection contracted by the mother during pregnancy, or to a genetic condition such as Fabry's disease, Alport syndrome, or galactosemia. Because clear vision is essential to the development of the child's eyes and brain, it is important to diagnose congenital cataracts as early as possible.
Find a Cataract Surgeon in Your Area
In their earliest stages, cataracts are often treated with stronger eyeglasses or contact lenses. Patients may also be encouraged to reduce the amount of glare to which they expose their eyes, or to use pupil-dilating eye drops that regulate the amount of light allowed into their eyes. When any of the cataract types begin to affect patients' daily activities, surgery is the recommended treatment. If you have been diagnosed with nuclear, subcapsular, or cortical cataracts and would like to learn more about treatment options, use our directory to contact a cataract surgeon in your area.