It is a cloudy area in the lens which causes blurrod or impaired vision. They mostly appear in old age, as advancing years bring a deterioration in the blood supply to the lens.
Causes
Congenital (present at birth), which may be due to:
- Maternal malnutrition
- Maternal infection especially virus of German measles or rubella
- Deficient oxygenation of placental haemorrhage
- Drugs in first trimester (e.g. Corticosteroids)
- Acquired (Damage to lens fibres already formed)
- Senile
- Traumatic
- Radiation
- Diabetes mellitus
- Hypothyroidism (Cretinism)
- Drugs e.g. corticosteroids
Complicated i.e. after inflammatory conditions of eye which can damage the lens.
Symptoms
- Gradual impairment of vision
- Objects appear multiple
- Rainbow haloes around light
- Lens opacity can be seen consistent with the symptoms
- Problems with visual activity in bright light or night driving