CATARACT
Meaning:
Opacity within lens
the patient may have a cataract in one or both eyes at any age for a variety of causes.
Incidence
According to the World Health Organization, cataract is the leading cause of blindness in the world
In India cataract has been reported to be responsible for 50-80% of the bilaterally blind in-the country
From around 1.2 million cataract surgeries per year in the 1980s, the cataract surgical output increased to 3.9 million per year by 2003. Recent data from the WHO shows that there is a 25% decrease in blindness prevalence in India
The 60+ population which stood at 56 million in 1991 will double by 2016. This increase in population means that the population 'at-risk' of blinding cataract will also increase tremendously.
Causes
- Aging:
Loss of lens transparency
Clumping or aggregation of lens protein (which leads to light scattering) Accumulation of a yellow-brown pigment due to the breakdown of lens protein
Decreased oxygen uptake
Increase in sodium and calcium
Decrease in levels of vitamin and antioxidants
- Associated Ocular Conditions / disorders
Retinitis pigmentosa
Myopia
Retinal detachment and retinal surgery
Infection (eg, herpes zoster, uveitis)
Iridocyclitis (iris & ciliary body- inflammation)
Onchocerciasis (skin infection due to infestation with oncocerca)
- Toxic Factors
Corticosteroids, especially at high doses and in long-term use
Alkaline eye burns,poisioning
Cigarette smoking
Calcium, copper, iron, gold, silver and mercury, which tend to deposit in the pupillary area of-the-lens
- Nutritional Factors
↓ antioxidant level
Poor nutrition
Obesity
- Physical Factors
Dehydration associated with chronic diarrhoea, use of purgatives in anorexia nervosa, and use of hyperbaric oxygenation
Blunt trauma, perforation of the lens with a sharp object or foreign body, electric shock
Ultraviolet radiation in sunlight
x-ray
People who live at high altitudes or who work in bright sunlight such as commercial fishermen
Glassblowers & welders who do not wear eye protection
- Systemic Diseases and Syndromes
- Diabetes mellitus
- Down’s syndrome
- Disorders related to lipid metabolism
- Renal disorders
- Musculoskeletal disorders
- Werner's syndrome (acute progeria, premature aging)
- Galactosemia (defect in the body's ability to use the sugar galactose.)
- Congenital factors like maternal rubella
- Infections:
- German measles
- Mumps
- Hepatitis
- Poliomyelitis
- Chicken pox
- Infectious mononucleosis
COMMENTS