Cataracts form in the crystalline lens of the eye or in ts envelope developing a clouding which can vary from slight to complete opacity. This clouding obstructs the passage of light into the eye. Approximately 48% of the world’s blindness is caused by age-related cataracts or around 18 million people worldwide.
Early in the forming of an age-related cataract myopia (near-sightedness) may develop and gradual yellowing and increasing opacity may reduce the patients perception of blue colours. Cataracts progress slowly causing vision loss and can be potentially blinding if untreated.
The cataract usually affects both eyes but one eye is always affected earlier. There are two types of cataract occurring in aged patients the first being senile cataracts. This is usually characterised by initial lens opacity, swelling of the leans which leads to shrinkage and complete loss of transparency.
In time the Cataracts cortex liquefies to form a Morgagnian cataract (milky white fluid) which will cause severe inflammation if the lens ruptures or leaks. If untreated cataracts can cause phacomorphic glaucoma
Signs and symptoms of cataracts
- Loss of visual acuity
- Contrast sensitivity is lost (contours, shadows, colour less vivid)
- Veiling glare
- Halo observed around street lights at night
Cataract high risk groups
- Commercial airline pilots (3x more likely)
- Those taking corticosteroids and seroquel
Causes of Cataracts
Cataracts may also be produced by physical trauma or eye injuries
When they are sufficiently developed they can be removed by surgery with the most common and effective treatment involves capsulotomy. The type types of eye surgery that is used to remove cataracts is intra-capsular (ICCE) and extra-capsular (ECCE). The first rare procedure ICCE involves removing the entire lens of the eye which includes the lens capsule. The second ECCE leaves a majority of the lens capsule intact but removes the lens. Phacoemulsification is sometimes used to break up the lens using high frequency sound waves before extraction. The benefit of cataract operations is that because they use local anaesthietic the patient is allowed to go home the same day. Some patients may choose to pay extra for a mulitfocal lenses.