Gradual Visual Loss Flashcards
What are cataracts
opacification of the lens causing decreased visual acuity
what is the leading cause of blindness in the UK
cataracts
by 100 years old, how many people get cataracts
basically 100%
How are cataracts characterised
by the anatomical location
what are the anatomical classifications of cataracts
posterior subcapsular cataracts
cortical cataracts
nuclear
what are some risk factors of posterior subcapsular cataracts
Diabetes
Steroids
What do posterior subcapsular cataracts do to vision
reduce acuity
reading distance affected the most
cause issues with direct bright light (as it gets refracted in the cloudy lens)
what are some risk factors of cortical cataracts
UV exposure
Diabetes
Drugs - corticosteroids, aspirin, K+ sparing diuretics
what do nuclear cataracts look like
yellowing nuclear sclerosis in the center of the lens
what are some risk factors for nuclear catarcts
milk intake
calcitonin
smoking
What is the aetiology of cataracts
Age-related Congenital Traumatic Metabolic Toxic (drugs) primary eye conditions systemic disease connective tissue disease CNS issues (sjorens, neurofibromatosis) Trisomy 21
what are risk factors for age related cataracts (apart from age)
allergy hyper/hypoension low IQ UV light infrared radiation Diabetes
how much of a genetic component do congenital cataracts have
about 1/3 are inherited
what are the types+ subtypes of congenital cataracts
total
partial - partial may be polar (ant or post), zonular (lamellar, stellate ,sutural, nuclear) or membranous
what causes traumatic cataracts
iris gets torn away from normal insertion causing damage
how do different types of trauma cause different types of traumatic cataracts
blunt trauma - rosette shape/posterior subcapsular
penetrating trauma whole lens opaque is large, is small usually a small area as it is self-sealing
What metabolic derangements cause cataracts
Diabetes Galactosaemia (GUPT deficiency) Galactokinase deficiency Wilsons Fabry's Lowes Decreased calcium menosidosis (genetic lysosomal disorder)
what kinds of cataracts do diabetes cause
snowflake opacities (only if true diabetic cataracts - otherwise may be age related)
what kind of cataracts are caused by galactokinase deficiency
lamellar opacity (wheel spoke)
what are causes of toxic cataracts
corticosteroids
chlorpromazine (anterior capsule)
chemo (buslphan)
what primary eye conditions cause cataracts
Uveitis
Hereditary retinal degenerations
High Myopia
Post Surgical
what systemic disease causes cataracts
cutaneous disease (atopic dermatitis)
congenital ectodermal dysplasia
werners/rothmond/thomson syndrome
what are immature, mature and hyper-mature cataracts
immature = not opaque fully yet mature = opaque hyper-mature = small wrinkled lens leading to fluid leakage
what are clinical features of cataracts
Decreased visual acuity
Glare (difficulty focusing in light)
Myopic shift (increase in refractive power causing slight-moderate myopia)
Mono-ocular Diplopia - double vision in one eye due to nuclear changes concentrating in inner refractive area in center of lens
