Week 1- Approach to Diseases of the lens Flashcards
What does a cataract lead to?
Blindness
What is the effect of nuclear sclerosis?
Doesn’t effect the vision
What is senile nuclear sclerosis a result of?
is a result of increasing density of the
secondary fibers
What is the function of retroillumination?
helps to distinguish cataract from nuclear
sclerosis- the full tapetal reflection is seen
What does a cataract refer to?
refers to a loss of transparency of the lens and leads to vision loss.
How are cataracts formed potentially?
Nutrition and waste removal is heavily reliant on aqueous humor due to a lack of a blood
supply to the lens
* Intraocular diseases that affect aqueous humor dynamics have potential to cause cataract
* Disruption of the lens fibres, increase in hydration and deposition of the lens protein
result in a loss of transparency
What does a cataract frequently lead to?
Frequently leads to blindness
What might a cataract be secondary to?
PRA(progressive retinal atrophy), anterior
uveitis, glaucoma, trauma, metabolic causes (e.g.
diabetes) dietary, toxic.
What are the 5 degrees of opacity for a cataract?
- Incipient
- Immature
- Mature
- Hypermature
- Morganian
How does a diabetic cataract occur?
Diabetes mellitus is a common cause of
a rapidly developing cataract
* Hyperglycemia altera metabolism of the
lens
* Due to osmotic forces the water from
the aqueous enters the lens
* Oedema of the lens fibers and vacuole
formation ensues
* The level of hyperglycemia does not
correspond with the progression of the
cataract
* Early surgery is generally indicated
What is lens induced uveitis?
Lens induced or phacoclastic uveitis
* Inflammatory reaction against lens proteins released from
diseased lens
* Often severe and difficult to control medically
* Can be assumed in all patients with mature and hypermature
cataract
* Must be recognized and treated before surgery
* Must be treated to prevent glaucoma and other secondary
complications
* Topical NSAIDs or corticosteroids, often long-term, is needed
to control uveitis
* Systemic NSAID may be required in severe cases
* Care must be taken with application of topical glucocorticoids,
especially if diabetes is present
What is the only available treatment currently available for cataracts?
- Surgery
- Short term therapy aimed at improving vision can be
considered in early-stage nuclear cataracts - Atropine 1% , 1 drop every 2-3 days, to effect (improves
peripheral vision as the pupil is dilated) - Medical management is aimed at treatment of cataract
complications (anterior uveitis)
What are the complications associated with cataracts surgery?
- uveitis
- lens fibre regrowth
- post-op spikes in IOP
- Intraocular haemorrhage
- Infection
- leakage from surgical site
What are the two types of lens luxation?
- Primary
- Secondary
What is posterior lens luxation?
luxation and glaucoma
* The major complication of any lens luxation is
glaucoma
