Cataract: Causes, Symptoms, and Treatment

Overview

Cataract is a condition characterized by the clouding of the eye's natural lens, resulting in blurred or foggy vision. It commonly affects the elderly but can also arise from other factors such as trauma, inflammation, or diabetes.

Relevant Medical Field

Cataracts fall under the specialty of Ophthalmology, which focuses on eye health.

Affected Organ

Cataracts impact the eye's lens, an essential part of the visual system.

Related Conditions

Some key contributors to cataract development include diabetes, aging, eye injuries, and inflammatory conditions.

Definition

The lens, located behind the iris and pupil, functions to refract light that enters the eye, focusing it onto the retina. Cataracts develop when the lens becomes cloudy, hindering the light from passing through properly. This causes vision to appear as though seen through a mist or fog.
Cataracts can be classified based on the area of the lens affected, including posterior subcapsular cataract, nuclear cataract, and cortical cataract.

Types of Cataracts

Cataracts are categorized into several types depending on the region and nature of the clouding:

• Posterior Subcapsular Cataract: Occurs at the back of the lens and is more common in people taking steroids or those with diabetes.
• Nuclear Cataract: Forms deep in the central part of the lens, often progressing with age.
• Cortical Cataract: Appears on the outer edges of the lens, resembling spokes of a wheel.

Causes

Cataracts can be congenital (present at birth) or acquired later in life. While many congenital cataracts have unknown causes, they may stem from genetic conditions or fetal infections. The most common form is age-related cataract, which occurs as part of the normal aging process. Other triggers include trauma, long-term use of medications like steroids, or conditions like diabetes and eye inflammation.

Symptoms

The severity of vision loss from cataracts depends on the location, size, and progression of the cloudiness in the lens. Some people may experience double vision in one eye, while others might notice near vision improvement despite prior farsightedness due to hardening of the lens (known as nuclear sclerosis). For example, an older person who had trouble reading may suddenly find close objects easier to see — a sign that cataracts could be developing.

Diagnosis

Cataracts are diagnosed through a slit-lamp examination after dilating the pupil. This allows the doctor to examine the lens and determine the type and extent of the cloudiness.
Based on the location of the cataract, it may be classified as:

• Anterior Subcapsular Cataract: Clouding at the front of the lens.
• Nuclear Sclerosis Cataract: Hardening and clouding of the central part of the lens.
• Posterior Subcapsular Cataract: Affects the back part of the lens, often seen in steroid users or those who have undergone eye surgery.

Treatment

Unfortunately, no medication can reverse cataract formation. While some eyedrops claim to slow progression, their effectiveness is not yet well-established. If cataracts significantly impair daily activities, surgery becomes the recommended solution. During cataract surgery, the cloudy lens is removed and replaced with a permanent artificial lens. This procedure is highly successful and rarely requires lens removal again unless complications arise.

Prognosis and Complications

Cataracts progress slowly, so surgery is generally advised only when daily tasks become challenging. If left untreated for too long, the lens can harden, complicating the surgical removal process. In extreme cases, known as mature cataracts, delayed treatment can lead to longer recovery times and suboptimal visual outcomes. Untreated congenital cataracts can result in amblyopia (lazy eye), leading to permanent vision impairment even after cataract removal.

Prevention

While congenital cataracts cannot be prevented, early detection is crucial for minimizing their impact. Age-related cataracts, although part of the natural aging process, may be delayed by protecting the eyes from ultraviolet (UV) light exposure. Wearing sunglasses outdoors can help reduce this risk. Additionally, those taking medications like steroids should undergo regular eye exams to monitor for cataract development.

Lifestyle and Dietary Guidance

Upon receiving an early cataract diagnosis, regular eye exams are necessary to monitor its progression. Timely surgery should be considered when vision impairment affects everyday activities.

Related Conditions

Cataracts can be linked to conditions such as diabetes, aging, eye injuries, and chronic inflammation.