Cataracts are a widespread eye condition where the natural lens inside the eye becomes cloudy, often associated with aging. Cortical cataracts are a specific type affecting a distinct part of the eye’s lens. This article explains what cortical cataracts are, how they develop, their visual impact, and available treatments.
Defining Cortical Cataracts
A cortical cataract is cloudiness forming in the cortex, the outer layer of the eye’s natural lens. It often begins as white, wedge-shaped opacities or streaks at the lens edge. These opacities gradually extend inward, sometimes resembling wheel spokes.
This clouding occurs when protein fibers within the lens cortex break down and clump. This disrupts the normal transparency of the lens, affecting how light passes to the retina. Unlike nuclear cataracts, which primarily affect the lens center and can cause a yellowish or brownish tint, cortical cataracts are distinguished by their peripheral location and spoke-like appearance.
How Cortical Cataracts Form
Cortical cataracts primarily arise from age-related changes in the eye’s lens. As people age, lens proteins and fibers alter, leading to gradual clouding. Age is the most common factor in their development.
Other factors increase the likelihood of cortical cataracts. Medical conditions like diabetes and hypertension are associated with higher risk. Diabetes, in particular, can lead to the accumulation of sorbitol in the lens, causing lens fibers to swell and become cloudy. Lifestyle choices such as smoking and prolonged exposure to ultraviolet (UV) radiation, especially UV-B rays, are also contributing factors. Eye injury, certain medications like corticosteroids, and even family history can also play a role.
Visual Impact of Cortical Cataracts
Cortical cataracts cause specific visual disturbances that often progress gradually. A common symptom is increased sensitivity to glare, especially from bright light sources like car headlights or reflected sunlight. This occurs because wedge-shaped opacities scatter light entering the eye, rather than allowing it to pass clearly.
Individuals may also experience blurred or hazy vision, which worsens in brightly lit environments. Increased brightness amplifies the light-scattering effect, reducing visual detail. Other symptoms include halos or rings around lights, difficulty discerning colors, making them appear faded or yellowish, and problems with depth perception. Double vision in one eye, known as monocular diplopia, can also occur.
Addressing Cortical Cataracts
Diagnosing cortical cataracts involves a thorough eye examination by an ophthalmologist or optometrist. The diagnostic process typically includes a visual acuity test, measuring how well a person sees at various distances. A slit-lamp examination uses a high-intensity light and microscope to view the lens and identify characteristic wedge-shaped opacities. Pupil dilation and a retinal examination may also be part of the assessment.
Non-surgical options like updated prescription glasses or anti-glare sunglasses offer temporary relief in early stages but do not stop progression. When cortical cataracts significantly impair vision and interfere with daily activities, surgery is the most effective treatment. The most common procedure is phacoemulsification, where an ultrasonic device breaks the cloudy lens into tiny pieces for suction removal. After natural lens removal, a clear artificial lens (intraocular lens or IOL) is implanted to restore vision. This outpatient procedure is generally quick, often lasting 10 to 20 minutes, and typically results in significant visual improvement.