Gradual visual loss Flashcards
What is a cataract?
Vision impairing disease characterised by gradual, progressive loss of transparency of the lens
What are the 4 stages of development of a cataracts?
1) Immature cataracts
2) Mature cataract
3) Hypermature cataract
4) Morgangnian cataract
What is an immature cataract
Lens partially opaque
What is a mature cataract
Anterior cortical changes sufficiently dense to obsccure the view of post lens
What is a hypermature cataract
Lens shrunken, lens capsule = wrinkled b/c leakage H2O
What is Morgagnian cataract?
Hypermature - total liquefaction of cortex
Nucleus sinks inferiorly
Clinical features of cataracts (5)
Decreased visual acuity Glare Myopic shift Monocular diplopia 'Blurry/misty vision'
Which type of cataracts are the majority?
Age-related cataracts
By 75, what % have lens opacities?
75%
By 100, what % have lens opacities?
100%
Factors causing cataracts (7)
Allergy HoTN HTN Mental retardation UV light IR radiation DM
What % congenital cataracts is inherited?
33%
When does juvenile cataracts develop?
During first 12 years of life
Appearance of juvenile cataarcts?
Snow-flake opacities in ant + post subcapsular location
Appearance of blunt trauma cataracts
Rosette-shaped appearance + PSC
Appearance of penetrating trauma cataracts
Whole lens may become cataractous if large
If small - localised @ site penetration
Causes of traumatic cataracts (3)
Glass blowers
Electric shock
IR
What is a true diabetic cataract?
Osmotic overhydration of lens –> post/ant lens opacities
Appearance of galactosaemia cataract
Oil droplet appearance
Appearance of galactokinase deficiency cataract
Lamellar opacities
Which drugs can cause PSC?
Corticosteroids
What can chlorpromazine cause?
Yellow deposits
Causes of high myopia
Glacuomfleken
Post-surgical
Appearance of atopic dermatitis cataracts
Fibrotic anterior subcapsular cataract
Appearance of myotonic dystrophy cataracts
Christmas tree appaerance
Apperance of Marfans cataracts
Ectopia lentis - lens displacement
Where is a PSC?
In front of posterior capsule
Appearance PSC?
Vacuolated/plaque like appearance
What is PSC associated with?
Steroid use
DM
What do people with PSC have issues with?
Bright sunlight/oncoming headlights
In PSC, is reading or distance vision better
distance vision
Where is a nuclear sclerotic cataract?
In lens nucleus
Nuclear sclerotic cataract appearance
Yellwish hue (early) --> brownish discoloration
What is Nuclear sclerotic cataract associated with?
Smoking
Calcitonin
Low milk intake
In NSC is reading or distance vision better?
Near vision
Appearance cortical cataracts
Starts as clefts/vacuoles in cortex between lens + fibres
–> opacification –> radial spoke like opacities
What are cortical cataracts associated with?
Enviro stressers; UV, DM, Dx ingestion, old age
When should you Tx a congenital cataracts if <2y/o?
Immediately
When should you Tx a congenital cataracts if 2-7y/o
within 1 week
Types of partial congenital cataracts (3)
Either planar, zonular or membranaceous
Types of zonular congenital cataracts (4)
Lamellar, stellate, sutural or nuclear
If vision is obstructed in congenital cataracts, what must be done and why?
Extraction within days/weeks
Prevent irreversible amblyopia
Differential diagnosis cataracts (3)
Macular degeneration
Presbyopia
Retinal disease
2 investigations required for diagnosis cataracts
Hx
Slit lamp exam for corneal intergrity/endothelial layer
When would you use a B-scan USS in cataracts
When fundus = obscured by dense cataract to rule out posterior segment disease
What can be used to predict post-op morbidities in cataracts
Pachymetry + specular microscopy
What factors should be considered before cataract surgery?
Degree disability Pt opinion Best correct visual acuity General health Coexisting ocular pathology Age
What is ICCE?
Intracapsular cataract extraction
When is ICCE used?
When zonular integrity = severely impaired
What is ECCE?
Removal lens nucleus through ant ccapsule opening
Post capsule integrity retained
What is PE?
Phacoemulsification
Extraction of lens nucleus through ant capsule opening
Irrigation + aspiration cortical material
IOL into post capsular bag
What is beneneficial about PE?
Smaller incisions means more rapid wound healing + better control IOP
Intraoperative complications cataracts
Capsular tear
Haemorrhage
Complications - when does retinal detachment usually occur?
Within 6 months
Complications - when does acute endophthalmitis usually occur?
Within 2-5 days
Features acute endophthalmitis?
Marked visual loss Pain Poor red reflex Educate Hypopyon
Tx acute endophthalmitis?
ABx
Within 3 years of cataracts surgery, what % –? post-capsular opacification?
10-50%
Tx post-capsular opacification?
Nd/YAG laser
