Ophthalmology - Cataracts Flashcards
What are cataracts?
Progressively opaque lens that reduces light entering the eye and visual acuity
What is the role of the lens in the eye?
To focus light on the retina
How is the lens held in place?
Suspensory ligaments attached to the ciliary body
How does the ciliary body affect the shape of the lens?
Contracts to thicken the lens; relaxes to narrow the lens
What nourishes the lens of the eye?
Aqueous humour
Lens has no blood supply, relies on aqueous humour
What are congenital cataracts?
Cataracts that occur before birth
Screened for using red-reflex during NIPE
List some risk factors for developing cataracts
- Increasing age
- Smoking
- Alcohol
- Diabetes
- Steroids
- Hypocalcaemia
How do cataracts present?
- Slow reduction in visual acuity
- Progressive blurring of vision
- Colours appearing faded, brown, or yellow
- Starbursts around lights, especially at night
- Glare and worse vision at night
- Myopic shift
What is myopic shift?
Patient becomes more short sighted due to increased refractive index of cataract
What is a key examination finding in cataracts?
Loss of the red reflex
Lens can appear grey or white when examined with ophthalmoscope
What does cataract surgery involve?
- Drilling and breaking the lens
- Removing lens pieces
- Implanting an artificial lens
What are some potenital complications of cataract surgery?
Retinal detachment
Can lead to vision loss if not treated promptly
Posterior lens capsule opacification
Most common
Occurs after a few weeks
Patient complains of blurry vision as if cataract has come back
White opacity may be visible on observation
Endophalmitis
Very rare
Bacterial infection causing inflammation
What can cataracts prevent from being detected?
Other pathology
- Macular degeneration
- Diabetic retinopathy
Reduced visual acuity may persist even after cataract treatment due to these underlying conditions.
What is endophthalmitis?
Inflammation of the inner contents of the eye, usually caused by infections
Most commonly caused by gram positive organisms
Ophthalmological emergency
How is endophthalmitis treated?
Intravitreal vancomycin
Most common causitive organisms post surgery are gram positive
Culture is taken from vitreous fluid
Why is vancomycin given intravitreously in endophthalmitis?
Poor penetration in ocular tissue
