Cataract
Overview of cataract
Development of Cataract
Types of Cataract
Risk Factors for cataract
Symptoms of cataract
Diagnosis and Tests of cataract
Treatment for cataract
Prevention of Cataract
Overview of cataract
As people grow older the natural eye lens become opaque leading to blurred vision. It is called cataract.
It is one of the leading causes of visual disability and preventable blindness.1 As the world’s population ages, cataract-induced visual dysfunction and blindness is on the rise. Genetic as well as environmental factors contribute to its development.2,3 It can occur in one or both eyes. It gradually develops over a long period of time and the loss of vision is gradual and painless, hence people do not realize till late that they have a cataract. Therefore, it is important to have regular eye check-ups especially after the age of 60 years.
The burden of cataract blindness is a major challenge for all developing countries.4 The blindness control efforts have been successful in arresting the increasing prevalence of blindness in India and there is hope that the goals of the ‘Vision 2020--right to sight’ initiative can be achieved if there is strong political will and prioritized action.5
During 1981–1982 India performed around 0.5 million cataract surgeries, and this increased to 4.8 million in 2006 with 90% intraocular lens acceptance.
Occurence of Cataract in Different Groups (epidemiology)
In India a nationwide survey was undertaken in 1999–2001 to document the magnitude and causes of blindness. The highest risk was among those aged 70 years and above and the illiterates. Cataract was responsible for 62.4% of bilateral blindness. Prevalence of cataract blindness was 5.3% (95% CI: 4.97–5.62). Reduction in blindness prevalence among people aged 50 years and above was observed compared to earlier studies.5
The biggest problem todeveloping countries in terms of human morbidity, economic loss,and social burden is due to pediatric cataract blindness.6A review of pediatric cataract cases operated between January 2003 and March 2005 in some parts of central India it showed congenital cataracts were in 88 (17.5%) eyes. Traumatic cataracts were noted in 170 (33.9%) eyes. The proportion of cataract was higher in males than in females.2
Development of Cataract
The lens is a clear part of the eye, which is made mostly of water and protein. It consists of three layers: the outer layer (capsule), the middle layer (cortex) and the inner layer (nucleus). It lies behind the iris and the pupil and focuses the light on the retina. In the older people the protein molecule on the lens clumps together and the lens become cloudy. It is usually start as a small, opaque spot and slowly grow larger. This cloudiness blocks the light reaching the retina, causing vision problems, which is called cataract. Vision is not usually affected until a large area of the lens becomes cloudy. Besides age related, there are less common types of cataract where lens become cloddy even in children and young people.
Types of Cataract
Types of cataract
Cataract is classified into three different types, depending upon the part of the lens affected.
Risk Factors for Cataract
The biggest risk factor for cataracts is aging. Other risk factors are
- Family history of cataracts
Additionally, some cataracts are congenital, meaning they are present since birth.
Symptoms of cataract
Cataracts are generally painless gradually developing condition. The most common symptoms are:
- Yellowing or fading of color vision
- Frequent change in spectacle prescriptions
Diagnosis and Tests of Cataract
Torch light examination can diagnose cataract. Iris shadow on the lens is seen as a milky white opacity.
Ophthalmoscopy: The lens media appears hazy.
General examination: To find out the conditions like diabetes or hypertension.
Detailed dilated eye examination including direct and indirect ophthalmoscopy can be done to confirm the condition.
A-scan ultrasonography: To determine the axial length of the eye and intraocular lens (IOL) power.
Complete blood investigation including bleeding time and clotting time.
Treatment of cataract
Treatment for cataract
Cataract is a progressive disease and treatment is essentially removal of lens followed by IOL or spectacles. Till date nowhere in the world an anti-cataract drug is approved for cataract.
Prevention of Cataract
Cataract is a natural age-related process and cannot be prevented. There are certain measures, which can reduce the risk of its development or can slow down its progression:
- By reducing exposure to UVB radiation wearing sunglasses and a hat with a brim and avoiding direct UV exposure.
A good nutritious diet including green leafy vegetables, fruits and other foods with antioxidants can help reduce the risk of age-related cataract.
The National Eye Institute suggests that if one with the age of ³60 years you should have an eye exam at least every 2 years.8 Widespread surgical services capable of delivering good vision rehabilitation accessible to all in need can help reducing disability and blindness.3Appropriate treatment at appropriate time can save the eye sight.
Written by: Healthplus24 team
Date last updated: April 28, 2012