Cataract

Everyone is born with a natural lens inside their eye, which helps to focus light on the retina. This is known as a crystalline lens. For most people, the lens will be clear from birth and easy to see through. However, over time, proteins inside the lens can clump together, thereby limiting the amount of light that reaches the retina. A thickened lens is called a cataract. The cataract can change your vision in different ways depending upon the size and location of the cataract. 

There may be no symptoms in the early stages other than a gradual decline in vision - cataracts do not cause abnormal tear production and are not a cause of discomfort or itching. However, if cataracts are not treated, then over time, they will get worse and eventually can cause blindness.

The older you get, the more likely you are to develop cataracts, with most people developing them anywhere from about the age of 50 onwards. In some cases, younger people may also develop cataracts for various reasons, but this is very rare.

It is common for both eyes to develop a cataract at the same time, although this is not always the case.

 

Types of Cataracts

Cataract can be categorized into the following four types. Some people will have more than one type of cataract present at the same time.

Nuclear Cataract

This type of cataract is the most common and affects the center of the lens. Initially, nuclear sclerosis of the lens may make you more nearsighted or improve your reading vision temporarily. The lenses gradually become more densely yellow and further cloud your vision as time passes. Eventually, the lens will turn brown. Browning or yellowing of the lens causes difficulty discerning different shades of color.

Cortical Cataract

This type of cataract affects the cortex of the lens. During the early stages of a cortical cataract, there are whitish streaks or opacities on the outer edge of the lens cortex. With time, the streaks spread towards the center of the lens and interfere with the passage of light. This is especially noticeable at night, manifesting as glare from headlights while driving in the dark.

Posterior Subcapsular Cataract

Cataracts that develop behind the lens are called posterior subcapsular cataracts. Subcapsular posterior cataracts begin as a small, opaque area located along the back of the lens, directly in the path of light. Cataracts in the posterior subcapsular lens can cause difficulty reading, reduce your vision in bright light, and create halos around lights at night. They also progress more quickly than other types of cataracts.

Congenital Cataract

Congenital cataracts are a cataract that you may be born with, which is a rare occurrence. They can also develop during childhood. An intrauterine infection or trauma can cause these cataracts, or they may be genetic.

Certain conditions could also cause cataracts. For example, myotonic dystrophy, galactosemia, neurofibromatosis type 2, or rubella may cause cataracts. Although congenital cataracts don't always impair vision, if they do, they're usually removed as soon as the condition is diagnosed.

 

Causes of Cataract

Aging is the primary cause of cataracts. In most cases, cataracts develop without any discernible cause. Here are some possible contributing factors:

  • A poor diet

  • Smoking

  • Affected by diabetes

  • Taking steroid medications

  • Family members have a history of cataracts, i.e., genetics

  • The sun's ultraviolet rays

  • Hypertension (high blood pressure)

  • Being overweight

  • Medications that lower cholesterol

  • Having previously injured or inflamed eyes

  • Past surgical treatment of the eyes

  • Drinking a lot of alcohol

  • Long-term use of hormone replacement therapy (HRT)

  • Significant nearsightedness (high myopia)

 

Symptoms of Cataract

Cataracts usually develop slowly over time and do not cause pain or redness until they have reached an advanced stage. Patients may experience a variety of symptoms and visual changes because of cataracts. These symptoms may include: 

  • Fuzzy, foggy, cloudy, or filmy vision 

  • A cloudy appearance to the pupil 

  • Light sensitivity or glare sensitivity

  • Poor distance vision, but good near vision 

  • Double vision (diplopia) or halo effects surrounding lights 

  • Constant changes in eye prescriptions 

  • Colors appear faded or yellowed

  • Having trouble seeing at night

  • Reading and other close-up activities require brighter lights

Diagnosis of Cataract

The presence of a cataract can be diagnosed by an ophthalmologist after a thorough eye exam. This should include a thorough medical eye examination. These tests include: 

Visual Acuity test 

This test determines the acuity and sharpness of your vision. Both eyes will be assessed individually for their ability to see small letters placed at a distance. Cataracts is often a cause for reduced visual acuity.

Slit-lamp exam

The cornea, iris, lens, retina, and other eye parts are examined under a microscope known as a slit-lamp. Usually, this test will be performed with your pupils widened after receiving dilating eye drops.

 

Treatment of Cataract

New prescription glasses and stronger lighting may help to alleviate early cataract symptoms. When cataracts make it difficult for you to carry out your daily tasks, such as reading or driving, surgery is recommended.

Surgery

Surgery is the only effective treatment once cataracts have progressed to the point that it interferes with daily activities and reduces your quality of life. In some cases, cataract surgery is necessary when other eye conditions cannot be treated effectively. This procedure is always performed in a hospital, usually under a light sedation.

The Procedure

The most common procedure used to perform cataract surgery is known as phacoemulsification. This involves making a small incision in the cornea (the clear, dome-shaped surface covering the front of the eye). The doctor then inserts a tiny probe through the eye. Using ultrasonic, this device softens and breaks up the lens, allowing it to be suctioned out. An implant lens is then inserted into the eye. The strength/power of this lens will be determined by preoperative measurements. The eye will then typically take around three weeks to heal, with recommendations given against strenuous activity during that period, including no bending, stretching or heavy lifting.

Prevention of Cataract

As of now, there is no scientific evidence that shows how to prevent cataracts or slow their progression. However, a few strategies may help:

  • Use sunglasses to avoid UV rays

  • Schedule routine eye exams

  • Quit smoking

  • Eat a healthy diet

  • Manage diabetes carefully and other medical problems