Week 1 - Crystalline Lens Flashcards
Nuclear sclerosis
Nuclear sclerosis
- haze in nucleus
- colour change ( white -yellow -brown)
- Glare and light loss
- Myopic shift
Cortical cataract
Cortical cataract
- wedges / Spokes in cortex
- starts peripherally with minor effect on VA
- glare
Can expand and coalescing of spokes
Posterior sub capsular ( PSC) cataract
Posterior sub capsular (PSC) cataract
- symptomatic with glare and reduced VA ( at near vision )
- progress very quickly
- difficult fundus examination
Christmas tree cataract
- not common
- polychromatic deposits in Cortex and nucleus
Mature cataract
- whole lens opaque
- surgery becomes difficult
Mature cataract - hypermature
- morgagnian cataract
- cortex becomes liquid
- nuclear sinks inferiorly
Congenital Cataract
- sight threatening / deprivation amblyopia
- babies have red reflex before discharge
- idiopathic
-hereditary
- maternal infection , drug use , malnutrition, metabolic errors , chromosomal abnormalities, prematurity
Axial or suture cataract
- chalky white cluster on or near the sutures
- doesn’t reduce vision
Blue dot cataract
- small blue dots in outer nucleus / cortex
- doesn’t impact vision as much
Secondary cataract ^ glaukomflecken
- result of another ocular disease ( anterior uveitis) ( primary angle closure glaucoma = glaukomflecken)
Secondary cataract - anterior uveitis
Toxic / induced cataract
Cataractogenic - induce cataract development
E.g - corticosteroid - PSC
- Antipsychotics - Chlorpromazine
Traumatic cataracts
- penetrating / blunt injury
- radiation cataract - ionising radiation used for tumour
- complicated surgery
- zonular dialysis - damage to zonular so less stable
Pseudo- exfoliation ( not a type of cataract )
- deposits of protein based material at pupil margin and anterior lens capsule
- important cause of secondary glaucoma ( pseudoexfoliative )
- increase risk of intra operative complication in cataract surgery
Epicapsular stars
- Iris pigment on the anterior lens capsule
Mittendorf dot
- Hyaloid remnant
•Mittendorf dot on posterior lens capsule
Iris Coloboma
- Congenital
•Caused by incomplete closure of the embryonic fissure
•Always inferior (nasal)
•Can be associated with choroid, retinal & optic nerve which may lead to reduced vision
Chorio-retinal coloboma
Disorder of lens shape and position
Lenticonus
•Anterior or posterior coning of lens surface
•Irregular lenticular astigmatism
•Can cause reduced vision
Ectopia lentis
•Subluxation or dislocation of the lens due to zonular rupture
•Can cause glaucoma & uveitis
•Causes of a dislocated lens
•Secondary to other pathology (e.g., Marfan’s, homocystinuria, familial, trauma, anterior uveal tumours, etc.)
Lens induced disorders
Glaucoma
•Phakomorphic (caused by lens shape/size)
•Phakolytic (capsular leakage)
•Lens displacement
•Uveitis
•Phakoanaphylactic (Auto Immune sensitivity to lens protein)
•Phakotoxic (toxic reaction to lens protein)
