Cataracts Flashcards
What is the structure of the lens?
The capsule: elastic and composed of collagen
The epithelium: anterior portion of lens between capsule and fibres, it is constantly laying down new fibres
The fibres: long, thin transparent cells stacked in layers
How does the lens remain transparent? How do cataracts develop? Causes of acquired?
It depends on the way the fibres (the transparent cells) are stacked and aligned in the lens
Cataracts arise from deposition of aggregated (clusters of) proteins, they’re not properly aligned, so there is clouding, light scattering and obstruction of vision.
There is also accumulation of yellow-brown pigment in the lens
Presentation of cataracts?
Gradual painless loss of vision
Difficulty reading, recognising faces
Diplopia in one eye
Haloes around lights
Picked up at opticians
Become more myopic (short sighted)
What causes cataracts in children?
What about adults?
Congenital: genetic, in-utero infection (TORCH)
Acquired: age, diabetes, trauma, post-radiotherapy
What are the TORCH infections?
Toxoplasmosis Other (herpes zoster, measles, EBV) Rubella Cytomegalovirus Herpes simplex
What are the signs on examination of cataracts?
Defect in red reflex, appears white (leukocoria)
Lens may appear yellow-brown (brunescent)
Poor visual acuity
Impaired view of retina
Management of cataracts?
When would you intervene?
Surgery: Phacoemulsification
Remove the lens and replace with artificial glass lens
Intervene if poor functioning, needed to perform other eye surgeries, if congenital, if caused by trauma
What are the results of congenital cataracts?
Weak ocular muscles causing poor visual acuity
Post-op complications of phacoemulsification?
Glaucoma
Retinal detachement
There are 3 types of cataract, what are they and what are the main causes of each?
Cortical: ageing, diabetes
Nuclear sclerosis: ageing
Posterior subcapsular: everything else
