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A cataract is the cloudiness or opacification of the natural lens in your eyes. The lens within your eye usually is clear as it allows light to travel through it and form images on the retina present in the back of your eyes. A cataract makes it cloudy or foggy, which disrupts light transfer. This can lead to partial or complete loss of vision in severe cases. It is a multifactorial disease that usually develops with growing age. It can be treated with surgery, but it can lead to complete blindness in a person if left untreated.


The most common cause of cataracts is growing age. Individuals over 40 years of age have a higher tendency to develop cataracts than children and young adults. This occurs because the natural proteins in your lens denature with growing age. The presence of physiological factors such as diabetes, hypertension, nutritional deficiency, etc., and environmental factors such as smoking, alcohol, radiation, etc., can increase its progression. Genetic factors are also linked with the development of cataracts. A few examples of genetic diseases that can cause cataracts include Down’s syndrome, Turner’s syndrome, rubella syndrome, etc. Traumatic injuries are another important cause. Direct or indirect traumatic injuries can cause thickening of the external eye tissues and lens, which can cause blurred vision. Other causative factors of cataracts include medications such as corticosteroids, post-surgical cataracts, skin diseases, systemic diseases, and pathogenic infections such as leprosy, varicella, etc. One factor or multiple factors may be linked at once in cataract development.

Risk Factors And Epidemiology

The primary risk factor for cataract development is age. Other risk factors are physiological, metabolic, genetic, and environmental causes. If you work in an open space directly under the sun (UV radiation) or somewhere with high ionizing radiation, there’s an increased risk of developing cataracts. Smoking and airborne irritants can directly affect the tissues of your eyes and lens. Alcohol intake, vitamin C deficiency, and other nutritional deficiencies are risk factors for cataracts. Diabetes, hypertension, and other metabolic diseases increase the risk of development or progression of already present cataracts. The use of topical or inhalational corticosteroids has also been noticed as a risk factor.
Approximately half of the cases of blindness around the world are associated with cataracts. The majority of those individuals are elders, usually over 55 or 60 years. It can affect both males and females. A cataract is more prevalent in countries with a low socio-economic status and radiation exposure.

Signs And Symptoms

Signs and symptoms associated with cataracts depend on the severity of the condition. Frequent complaints include blurred or foggy vision, reduced color intensity, double vision, reduced vision especially at night, seeing halos around bright objects, and increased sensitivity to glares of light. It has been often noticed that people with cataracts have more difficulty reading and recognizing objects from far than near ones. Even in broad daylight, reduced vision can impede several daily routine works. Therefore, many cataract patients have also been observed to develop depression and frequent irritability.


The cataract diagnosis requires a complete history and detailed clinical examination of the eye. It is important to consult an ophthalmologist (eye doctor) for this condition. Your doctor will ask for relative symptoms, habits, profession, and medical history to diagnose the possible cause of a cataract. Multiple tests may be performed to determine the severity of the cataract. A basic test is the visual acuity test which determines the ability of a person to read a series of letters from a certain distance. A slit-lamp examination may be performed to view the abnormalities associated with your vision in a magnified perspective. In some cases, a retinal exam is also suggested to view the retina by a slit lamp or ophthalmoscope. If another genetic or systemic disease is suspected, which may cause a cataract, your doctor will recommend appropriate tests and imaging techniques to identify the primary cause.

Differential Diagnosis

Cataracts should be differentiated from other conditions that might present with similar conditions. These conditions include glaucoma, retinoblastoma, diabetic retinopathy, sclerosis of the cornea, macular degeneration.


The conventional method for treating cataracts is a surgery in which the affected lens is replaced with an artificial intraocular lens. Two methods of cataract surgery are commonly used: phacoemulsification surgery and extracapsular cataract surgery. An eye specialist or ophthalmologist performs the surgery. It can be done under local anesthesia and does not require general anesthesia in most cases. Replacement of a natural lens with an implanted lens significantly improves the person’s vision suffering from cataracts. Thousands of people, especially elders, opt for cataract surgery to improve their vision. Post-op instructions are to be followed as advised by your doctor. Active or passive smoking, going in high radiation zones, and lifting heavy things may be prohibited or lessened to reduce the risk of any complications.


Surgery and supportive care is the primary mode of treatment for cataract. There are no effective medications available to treat this condition.


The prognosis of surgically treated cataracts is excellent. Over 90% of the affected patients regain improved vision after surgery. However,  if the cataract is left untreated for a long time, it can lead to partial or complete vision loss. Untreated cataract has been recorded as one of the leading causes of blindness globally.


Prevention of cataracts involves understanding its causative agents and risk factors. Since cataract is more prevalent among the elderly population, people over the age of 50 should manage their health well and have the proper nutrition to avoid any deficiency (especially of vitamin C). If they have secondary diseases such as diabetes, hypertension, etc., they should be managed with regular exercise, dietary restrictions, and medications to reduce the risk of cataracts. Going into the sunlight for long hours or high radiation areas should be avoided. Wearing UV-protection glasses or hats is recommended for older adults when going out for traveling or other purposes. Smoking and alcohol consumption should also be reduced.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 14, 2023. 


Cataracts | National Eye Institute (,to%20get%20rid%20of%20cataracts.

Cataract and systemic disease: A review - Ang - 2021 - Clinical & Experimental Ophthalmology - Wiley Online Library

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