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Last updated April 24, 2018

Approved by: Maulik P. Purohit MD, MPH

Cataract is defined as opacification (to become opaque) or clouding of the natural clear lens that results in visual problems, including blindness.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Age-Related Cataract
  • Lens Opacity 

What is Cataract? (Definition/Background Information)

  • The lens is a part of the eye that helps in focusing light or an image on the retina, located at the back of the eye. The retina is the eye's light-sensitive layer that sends visual signals to the brain
  • In a normal eye, light passes through the lens and gets focused on the retina. But, in order to help produce a sharp image, the lens must remain clear
  • Cataract is defined as opacification (to become opaque) or clouding of the natural clear lens that results in visual problems, including blindness
  • The word cataract means ‘waterfall’. Patients with early cataract see everything, as if they are seeing through a ‘misty’ glass window
  • A surgery is the most common, preferred, and effective treatment for Cataract. The prognosis is excellent with early diagnosis and surgery 

There are various types of Cataract and these include:

  • Age-Related Cataract
  • Congenital Cataract
  • Secondary Cataract
  • Traumatic Cataract
  • Radiation Cataract 

Who gets Cataract? (Age and Sex Distribution)

  • Cataracts are generally associated with the ageing process. All individuals, above the age of 45 years are susceptible to Cataract, though the condition becomes more apparent, generally after the age of 60 years
  • Congenital Cataract is a rare condition that affects very young children (including babies) 

What are the Risk Factors for Cataract? (Predisposing Factors)

The risk factors which increase the occurrence of Cataract include:

  • Advancing age
  • Individuals with diabetes
  • Smoking
  • Excessive consumption of ‘illegal’ drugs and alcohol
  • Continuous and too much exposure to sunlight
  • Being exposed to ionizing radiation, like that used in x-rays and cancer therapy
  • Family history of Cataracts
  • High blood pressure
  • Obesity or over weight conditions
  • Inflammation or eye injury, occurred previously
  • Use of corticosteroids for a long time
  • Any trauma affecting the eye (eye injury, surgery) 

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider. 

What are the Causes of Cataract? (Etiology)

  • The lens of the eye is made up of water and protein. The proteins in the lens are arranged in a particular manner, which helps keep the lens clear
  • This allows light to pass through the lens, making a clear vision possible
  • But due to ageing process, the proteins join together and form a shadow over the lens, affecting the clarity of the vision. This condition is termed as Cataract 

What are the Signs and Symptoms of Cataract?

  The signs and symptoms manifested by Cataract are:

  • Blurred  or unclear vision
  • Appearance of small dots, red spots, or small patches in the eye
  • Vision ability decreases in dim light
  • Vision becomes bad, while facing a bright light
  • Problems in clarity, while identifying color
  • Reading is possible only partially, or sometimes entirely not possible
  • Needing to change glasses regularly; after a while wearing glasses also becomes ineffective
  • ‘Second sight’ - some individuals may observe an improving near vision, with progression of Cataract. But, they eventually become visually compromised
  • Chances of developing double vision
  • In some cases, the individual can become transiently blind, when exposed to bright lights. Example: Like while driving at night, the vehicles heading towards you, shines bright headlights
  • Increased eye strain, while doing any activities
  • When the Cataract is fully mature it may give indications like:
    • Inflammation
    • Headache
    • Pain 

How is Cataract Diagnosed?

Any individual with vision problems should immediately visit an ophthalmologist and an optometrist. The following tests and exams may be used by a healthcare provider to diagnose a Cataract:

  • Visual acuity tests:
    • The sharpness of the vision is tested through this test
    • The patient is required to read a chart, called Snellen eye chart, with different letter sizes, to detect the acuteness of vision
    • The patient is required to read the chart, both with and without bright lights, to measure glare sensitivity
  • Slit lamp examination:
    • This is a special type of microscope, which allows the specialist to see the eye structure in small sections, so that even minute defects of the eye can be early identified
  • Retinal examination:
    • Eye drops are applied to dilute the pupils
    • When the pupils are diluted, it enables the specialist to check, if the eye is affected by Cataract. If so, the density of the Cataract and the presence of any other defects or eye disease, may also be observed
    • Driving should be avoided for a period of about 6-8 hours, after dilated fundus examination
  • Measuring protein related to Cataract formation:
    • A technique called dynamic light scattering, based on laser lights, are used to measure proteins related to Cataract formation 

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis. 

What are the possible Complications of Cataract?

Following are the possible complications of Cataracts:

  • Blindness: When left untreated, Cataracts can lead to loss of vision and blindness
  • Hypermature Cataract: Cataract that has reached an advanced level may reach into other parts of the eye, resulting in glaucoma and eye inflammation 

How is Cataract Treated?

Surgery is the curative treatment for Cataract. However, certain measures may be followed to control and manage the disease during the initial stages:

  • Use of suitable glasses that are to be based on accurate prescription, as far as possible
  • While reading, the use of a magnifying glass can help
  • Making the house or office spaces brighter using suitable lamps (such as halogen lamps) can be very helpful
  • Wearing sunglasses on sunny days will reduce glare
  • Driving in the night should be avoided, as far as possible.
  • Early surgery is recommended for individuals, even during the early stages of Cataract, if it interferes with their day-to-day activities, or if it interferes with their job/profession


  • Phacoemulsification or extracapsular extraction surgery is performed, wherein the cloudy lens is replaced by an artificial intraocular lens
  • This surgical procedure is generally performed under local anesthesia (through injection around eye, or topical instillation) and usually lasts only a short time period
  • Before the surgery, patients on medications, like alpha-blockers for frequent urination (such as benign prostatic hyperplasia), should inform both their nephrologist and eye surgeon, since an intake of alpha-blockers (or such medications) may lead to complications, during surgery for Cataract extraction

Other procedures may include:

  • Manual extra capsular extraction: A slightly bigger cut is made on the eye and the lens is removed in one piece, without the use of ultrasound
  • Intracapsular extraction: Under this method, both the lens and its capsule are removed and the artificial lens is sewn into the eye. However, this technique is rare, obsolete and performed, only in certain special situations 

How can Cataract be Prevented?

The following measures may be considered to prevent the development of Cataracts:

  • Regular eye examination: As an individual becomes older, this is the first step to preventing Cataract
  • Avoiding smoking helps prevent Cataract and other eye diseases
  • Nutrition: Having a diet filled with lot of fruits, vegetables, grains, carbohydrates, fats, and proteins
  • Wearing good quality sunglasses (which can block UV rays) and protecting one’s eye from bright sunlight will help in reducing the risk
  • Having 7 hours of sleep each day will reduce the strain on one’s eyes
  • Obesity is a main risk factor for developing Cataract. Hence, reducing the body weight will help in reducing the chances of Cataract formation
  • Diabetes: All individuals who are diabetic, must follow a treatment plan to properly and effectively manage diabetes
  • Exercise: Certain exercises, like jogging and running, have proved to be beneficial in reducing the occurrence of Cataract 

What is the Prognosis of Cataract? (Outcomes/Resolutions)

  • An early diagnosis with effective and immediate treatment of Cataract yields a good prognosis
  • However, in certain individuals, who are operated on for Cataract, a near perfect vision may not be restored, if the patient suffers from other underlying eye diseases, like macular degeneration 

Additional and Relevant Useful Information for Cataract:

  • Cataract extraction is a surgical procedure involving the removal or extraction of a cataract 

The following article link will help you understand cataract extraction surgical procedure.

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Sept. 11, 2014
Last updated: April 24, 2018