Cortical cataracts occur when fibers in the outer edges of a person’s lens start to break down and clump together. This makes the lens appear cloudy and can cause a person’s vision to become hazy, blurry, or less colorful.

Cataracts typically start forming after age 40 years, and most Americans over 80 years have cataracts or have had surgery to remove their cataracts.

This article explores cortical cataracts, including the condition’s progression, symptoms, causes, and more.

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The lens in the eye is a fibrous structure that sits right behind the pupil. Its job is to direct light to the back of the eye and change shape to help a person focus on things at different distances.

The lens has two parts: the outer layer, which experts call the cortex, and the inner layer, which they call the nucleus.

Cortical cataracts occur when proteins in the outer cortex layer of the lens start to break down and clump together. Over time, these groupings can grow thicker and make it harder for a person to see.

Without medical intervention, cortical cataracts can progressively spread inward and cover the entire lens surface.

The rate at which cataracts develop for each person varies, and doctors cannot predict how quickly a person’s cataracts will progress.

Cortical cataracts can cause several vision problems. These symptoms typically progress over several years and include:

  • Blurry vision: Clouding of the lens can cause things to appear blurry or hazy.
  • Decreased color perception: Cortical cataracts can change how a person perceives colors, making things appear faded or yellowed and making it harder to distinguish between color hues.
  • Glare sensitivity: Individuals with cortical cataracts may experience increased sensitivity to bright lights or the perception of halos around lights. This can make it more difficult to see or drive at night.
  • Double vision: Some people with cortical cataracts see double or distorted images.

The most common cause of cortical cataracts is the natural aging process, leading to changes in the structure of the lens. After the age of 40 years, the proteins in the lens start to break down.

While very rare, a genetic abnormality can cause a child to have cataracts. Only 1–15 children out of 10,000 experience congenital cataracts.

Experts are still studying the exact cause of cataracts. They have found several risk factors that may increase a person’s risk of developing cataracts. These include:

  • diabetes
  • severe eye trauma
  • a family history of cataracts
  • eye surgery for glaucoma or another eye condition
  • steroid medications
  • radiation treatment for cancer
  • smoking
  • overconsumption of alcohol
  • spending lots of time in the sun without eye protection

To diagnose cortical cataracts, a person needs a comprehensive evaluation by an ophthalmologist or eye doctor. This includes a thorough medical and vision history and eye examination.

For the medical history, the doctor will ask questions about a person’s medical conditions, vision symptoms, and previous eye exams.

The eye examination may include several tests to check the structure and function of the eye. At some time during the testing, the doctor may use eye drops to dilate the pupil to see the inside of the eye. The tests the doctor may use include:

  • Visual acuity test: This includes standing at a distance from a Snellen chart to determine how well a person can see.
  • Slit-lamp exam: This test involves using a slit-lamp microscope to examine the structures of the eye, including the cornea, iris, and lens.
  • Retinal exam: When the doctor dilates the eye, they will use a slit lamp or ophthalmoscope to look for conditions such as cataracts, glaucoma, or abnormalities on the retina or optic nerve.

Treatment for cortical cataracts depends on the severity of the condition and the underlying cause.

People experiencing mild symptoms of cortical cataracts may only require prescription glasses to improve their symptoms.

However, if their cortical cataracts are developing due to an underlying condition such as diabetes, it is important to manage the underlying condition effectively.

For individuals with more severe symptoms of cortical cataracts and whose vision is more impaired, the only way to remove the cataracts is through surgery.

During cataract surgery, the doctor removes the cloudy lens and replaces it with an artificial intraocular lens (IOL).

Over time, a person who had cataract surgery may experience cloudy or hazy vision again when the capsule — the part of the eye that holds the lens in place — becomes cloudy. The doctor can restore clear vision by performing a capsulotomy to remove the cloudy areas.

A person may not be able to prevent all risk factors for cataracts, but making some lifestyle changes may lower the risk of developing cortical cataracts:

  • UV protection: Wearing sunglasses that block ultraviolet (UV) rays can help protect a person’s eyes from the harmful effects of prolonged sun exposure.
  • Smoking cessation: Quitting smoking, if applicable, will benefit an individual’s overall health and may reduce their risk of developing cortical cataracts.
  • Managing diabetes: People with diabetes can reduce their risk of cortical cataracts by learning to manage their condition and maintain their blood sugar in a healthy range.
  • Limit alcohol consumption: Limiting how much alcohol a person consumes may help decrease their risk of developing cortical cataracts.
  • Regular eye exams: Getting regular eye exams after the age of 60 years — or sooner, if a person is at high risk of cataracts — can help detect the condition early and allow for timely intervention.

Once cortical cataracts start to form, they may gradually worsen and cover more of the lens. This causes a person’s vision to become more cloudy and blurred.

At first, glasses may help them see better, but if they do not seek treatment for cortical cataracts, the condition may lead to blindness.

However, surgical treatment typically restores a person’s vision. The person must follow their doctor’s recommendations after surgery and keep up with all follow-up visits.

Cortical cataracts are an age-related visual impairment that affects the lens of the eye. Cortical cataracts develop when fibers in the lens break down and form clumps in the outer edges of the eye. Over time, cortical cataracts can progress toward the center of the lens.

Typical symptoms include changes in vision, such as blurry or hazy images, and decreased color perception. Some people also notice halos around lights, feel more sensitive to glare, and have trouble seeing at night.

Treatment typically involves surgically removing the affected lens and implanting an artificial lens. In most cases, this procedure restores a person’s vision. Regular eye exams are key to maintaining optimal eye health as a person ages.