Cataracts Flashcards
What are some of the major factors contributing to cataract development?
Congenital - maternal nutrition, Rubella, placental haemorrhage resulting in o2 deficiency
Age-related - senile cataract
Trauma - perforating trauma, blunt trauma (flower-shaped opacity), electric shock (snowflake-like opacity), UV, ionising radiation, chemical (naphthalene, thallium, lactose, galactose)
Systemic diseases - myotonic dystrophy, atopic dermatitis, neurofibromatosis type 2
Endocrine - DM, hypoparathyroidism
Ocular - chronic anterior uveitis, acute congestive angle closure, high myopia, hereditary funds dystrophies eg RP
Drugs - corticosteroids, ACh inhibitors
Poor nutrition, alcohol, smoking
What are the two main parts that make up lens matter?
Cortex - superficial part, contains younger fibres
Nucleus - deeper part, contains older fibres
What are the main types / stages of cataract?
Congenital (disturbances occur at any level of lens growth)
Subcapsular (fibrous metaplasia of lens epithelium occurs)
Cortical (cortical hydration between lens fibres occurs)
Nuclear (results from deposition of certain pigments eg urochrome)
What are the common symptoms of cataracts?
Decreased / blurred vision - gradual, painless
Diplopia - due to multiple refractions through clear areas between opacities
Coloured haloes - collection of water between layers of lens fibres refract light
Glare
Disturbance in colour vision - yellowing or fading of objects
What is the medical treatment for cataracts?
If VA is 6/24 or better –> pupillary dilatation with 2.5% phenylephrine or refractive glasses
Cyclopentolate and atropine may also be used
NB medical treatment is ineffective once the cataract has matured
How does atropine work?
Antimuscarinic
Acts as a mydriatic and cycloplegic
(Similar to cyclopentolate)
What are mydriatics and cycloplegics?
Mydriatic = dilates pupils Cycloplegic = paralyses ciliary muscles causing loss of accommodation
What are the indications for surgical treatment?
If VA is worse then 6/24
Medical indication causing cataract to adversely affect the health of the eye eg phacolytic / phacomorphic glaucoma or retinal detachment
What are some complications of congenital cataracts?
Corneal ulcer, corneal perforation, blindness
From surgery - uveitis, posterior capsular thickening, aphakia, retinal detachment, glaucoma
What are some complications of acquired cataracts?
Acute congestive glaucoma, iritis, subluxation of the lens, blindness
From surgery - hyphaema, corneal burn, iris prolapse, endophthalmitis / panophthalmitis
