Opthalmology Flashcards
1
Q
Define cataracts
A
- Most common cause of curable blindness in the world
- The opacification of the crystalline lens that results from the normal ageing process, trauma, metabolic disorders (hereditary or acquired), medications, or congenital problems.
2
Q
Describe epiemiology of cataracts
A
- 51% of preventable blindness world wide
- 20 million people
- Cataract surgery is the most frequent surgery in the NHS
- 400000 surgeries per year in England
3
Q
List risk factors for cataract
A
- Age over 65
- Smoking
- UV exposure
- Diabetes mellitus
- Eye trauma
- Long term corticosteroid use
- Family history
- Uveitis
- Metabolic/hereditary conditions
4
Q
List symptoms of cataract
A
- Decrease in vision
- Blurred or cloudy vision
- Glare
- Washed out colour vision
5
Q
List signs of cataracts
A
- Disruption in ADL
- Reduced visual acuity
- Defects in the red reflex
6
Q
Describe investigations of cataracts
A
- Dilated fundus examination (normal)
- Measure intraocular pressure (normal)
- Glare vision test
- Slit lamp examination of the anterior chamber (visible cataract)
- Assessment of best visual potential
7
Q
Define closed angle glaucoma
A
- A group of diseases in which there is reversible (appositional) or adhesional (synechial) closure of the anterior-chamber angle resulting in elevation of the intra-ocular pressure (IOP).
- The angle closure may occur in an acute or chronic form.
- In the acute form, the IOP rises rapidly as a result of relatively sudden blockage of the trabecular meshwork by the iris, via the pupillary block mechanism
- The chronic form may develop after acute angle closure where synechial closure of the angle persists. It may also develop over time, as the angle closes from prolonged or repeated contact between the peripheral iris and the trabecular meshwork, which often leads to peripheral anterior synechiae (PAS) and functional damage to the angle.
8
Q
Define open angle glaucoma
A
- A neurodegenerative condition primarily due to dysfunction in outflow of the nutrient-rich fluid, aqueous humour that constantly flows through the eye.
- Aqueous humour, created in the ciliary body, passes through the pupil into the small area between the iris and the cornea, called the anterior chamber.
- The fluid then flows into the periphery of the chamber known as the anterior chamber angle.
- This angle is where the fluid travels through the trabecular meshwork and into blood vessels.
- Open-angle glaucoma is characterised by an anatomically open angle but with an obstructed and slowed drainage system outflow.
9
Q
Describe epidemiology of glaucoma
A
- 2nd leading cause of blindness in the world
- Primary open angle accounts for 70% of cases
- Higher prevalence of open angle in African populations
- 1/3 primary closed angle claucoma
- Highest rate of closed angle in asian populations
- Women are 2-4 times more likely to have ACG, and it is most common age 55-65
10
Q
Describe aetiology of closed angle glaucoma
A
- Thick cataractous lens, ectopic lens and neovascularisation secondary to diabetic retinopathy and tumors can cause glaucoma
- Sulfa containing drugs can cause supraciliary body effusion
11
Q
Describe aetiology of open angle glaucoma
A
- Retinal ganglion cells slowly degenerate. It has been linked to hereditary factors.
- A gene at the GLC1A locus is associated with adult- and juvenile-onset open-angle glaucoma.
- Myocilin mutations have been described in people with primary open-angle glaucoma.
12
Q
List risk factors of open angle glaucoma
A
- Intra ocular pressure (over 23mmHg)
- Age over 50
- Family history of glaucoma
- Black ethnicity
- Myopia (long eyeball)
- Diabetes mellitus
- Hypertension
- Hypothyroidism
13
Q
List risk factors of closed angle glaucoma
A
- Female
- Hyperopia (small eyeball)
- Shallow peripheral anterior chamber
- Second eye angle closure
- Inuit and Asian ethnicity
- Older age (55-65)
- Family history
- Medications
14
Q
List symptoms and signs of closed angle glaucoma
A
- Halos around eyes
- Aching eye or brow pain
- Headache, nausea, vomiting
- Reduced visual acuity
- Eye redness
- Elevated IOP
- Corneal oedema
- Fixed dilated pupil
- Incidental eye findings
- Blurred vision
- Change in vision
- Eye feels hard
- Corneal haze
15
Q
List symptoms and signs of open angle glaucoma
A
- Cup to disc ration over 0.4
- Notching of optic nerve cup
- Peripheral vision less (painless)
- Increased intra-ocular pressure
- Scotomas
- Loss of nerve fibre layer
- Retinal haemorrhage
16
Q
List investigations for closed angle glaucoma
A
- High Intra-ocular pressure
- Corneal oedema
- Vascular congestion
- Fixed, dilated pupil
- Gonioscopy: shallow chamber & closed angle
- Slit-lamp/fundoscopy: Large optic cup, nerve fibre loss.
17
Q
List investigations for open angle glaucoma
A
- Tonometry (raised intraocular pressure)
- Direct opthalmoscopy (Cup to disc ratio increased, flame haemorrhages)
- Indirect opthalmoscopy (3d view of disc cupping)
- Slit lamp biomicroscopy (open drainage angle)
- Visual field testing
CONSIDER
- Gonioscopy
- Photographs of the optic nerve head
- Pachymetry
- Nerve fibre layer analysis
- Optical coherence tomography scanning
18
Q
Compre acute, sub-acute and chronic closed angle glaucoma
A
Acute = sudden episode of pain, nausea, blurred vision
- Corneal oedema
- Fixed,dilated pupil
- Very elevated IOP
- Gonioscopy: Anterior chamber angle closed
Sub-acute = sudden symptoms but self-limiting, recur
Chronic = no symptoms, found incidentally
- Elevated IOP
- Normal optic head
- Gonioscopy: Anterior chamber angle closed
19
Q
Define hollenhorst plaque
A
An embolus formed from cholesterol deposition, typically originates from the ipsilateral carotid arteries
- Appear as refractile crystal like emboli, usually lodged in arteriole bifurcations
20
Q
Define trachoma
A
- Worlds leading cause of blindness
- Caused by Chlamydia trachomatis
- 1.8 mill people have visual impairment because of it
- Conjunctivitis in the early stages (with discharge from the eyes), progresses to cause scaring and eyelashes turning inward (trichiasis), which leads to corneal ulcers
21
Q
Describe retinal detachment
A
- Sudden flash of light, floaters and a loss of peripheral vision
- Dark curtain moving across vision
- Needs urgent treatment
