Ophthalmology: Gradual loss of vision Flashcards
what is open angle glaucoma?
In open angle glaucoma, there is a gradual increase in resistance through the trabecular meshwork. This makes it more difficult for aqueous humour to flow through the meshwork and exit the eye. Therefore the pressure slowly builds within the eye and this gives a slow and chronic onset of glaucoma.
nb: increased pressure causes cupping of the optic disc - An optic cup greater than 0.5 the size of the optic disc is abnormal.
what are the risk factors for a open angle glaucoma?
- Increasing age
- Family history
- Black ethnic origin
- Nearsightedness (myopia)
how does open angle glaucoma present?
- asymptomatic for a long period of time
- Glaucoma affects the peripheral vision first. Gradually the peripheral vision closes in until they experience tunnel vision.
what is meant by cataracts?
Cataracts are where the lens in the eye becomes cloudy and opaque. This reduces visual acuity by reducing the light that enters the eye.
what are some risk factors for cataracts?
Increasing age Smoking Alcohol Diabetes Steroids Hypocalcaemia
how does cataracts present?
Symptoms are usually asymmetrical as both eyes are affected separately. It presents with:
- Very slow reduction in vision
- Progressive blurring of vision
- Change of colour of vision with colours becoming more brown or yellow
A key sign for cataracts is the loss of the red reflex. The lens can appear grey or white when testing the red reflex. This might show up on photographs taken with a flash.
with reference to the eye:
The loss of the red reflex may appear grey or white when testing the red reflex. This might show up on photographs taken with a flash. What is this characteristic of?
cataracts
what is the management of cataracts?
if you can manage symptoms then no intervention necessary
cataract surgery: drilling and breaking the lens into pieces, removing the pieces and then implanting an artificial lens into the eye.
- day case
- local anaesthetic
what is the most common cause for blindness in the uk?
Age related macular degeneration
two types:
- wet (10%) - worst prognosis
- dry (90%)
the macular of the eye is made up of what 4 layers?
- choroid layer (blood vessels)
- Bruch’s membrane
- retinal pigment epithelium
- photoreceptors
with reference to the eye:
what is Drusen and what can it be a sign of?
Drusen are yellow deposits of proteins and lipids that appear between the retinal pigment epithelium and Bruch’s membrane of the macular
Larger and greater numbers of drusen can be an early sign of macular degeneration.
what are some risk factors of age-related macular degeneration?
Age Smoking White or Chinese ethnic origin Family history Cardiovascular disease
how does age-related macular degeneration present?
Gradual worsening central visual field loss
Reduced visual acuity
Crooked or wavy appearance to straight lines
