Cataracts Flashcards
What are cataracts?
Opacification or clouding of crystalline lens of eye
This reduces light entering the eye and leads to lower visual acuity
Most common cause of reversible blindness
The role of the lens
Focuses light on the retina
Composed of modified epithelial cells
Held in place by suspensory ligaments attached to the ciliary body
Degradation and coagulation of lens proteins leads to opacity
Causes of cataracts
Old age (most common)
Endocrine - diabetes, hypoparathyroidism, hypocalcaemia, Wilson’s disease
Systemic diseases - atopic dermatitis, myotonic dystrophy, HIV
Ocular diseases - retinitis pigmentosa chronic anterior uveitis, high myopia
Medications - glucocorticoids, ACE inhibitors
Substances - alcohol, smoking
Trauma - blunt, penetrating, eye surgery, UV/ionising radiation
Congenital - toxoplasmosis etc
Cortical cataracts
Affects cortex of lens
Have radial spokes
Often due to diabetes and ageing
Nuclear sclerosis cataracts
Affects nucleus/centre of lens
Yellow or brown colour
Often due to ageing
Posterior subcapsular cataracts
Affect posterior portion of lens
Grainy appearance
Can be due to ageing, diabetes, trauma, steroid use
Cataract signs and symptoms
Vision loss (painless, progressive, gradual)
Distance affected more than near vision
Issues with glare - starburst, halos
Colour perception changes
Second sight phenomenon - increased myopia (don’t need reading glasses any more)
Loss of red reflex on exam
Diagnosing cataracts
Either overt or on slit lamp (ophthalmoscopy is not ideal)
Cataract treatment
No medical treatment
Surgical removal of lens
Replacement with artificial lens
Possible complication - endophthalmitis (inflammation of inner eye contents)
