Ophthalmology Flashcards
What is the axial length of the eye?
23mm
What are the two main refracting surfaces of the eye?
Cornea
Lens
What is the centre of the retina?
Macula
Where does image focus in myopia?
Before the retina
‘Short-sight’
Where does image focus in hypermetropia?
After the retina
‘Long-sight’
How many bones comprise the eye orbit?
7
What causes double vision?
Misalignment of visual axis
What is in-sinking of the eye called?
Enopthalmos
When does facial development occur in uterto?
4-8 weeks
When does the optic vesicle develop?
4 weeks from forebrain
What is coloboma?
Disruption to eye development
Can occur to iris or retina
What are the main features of newborn eyesight?
Can not focus 20-30cm ways
High contrast
Cannot move between two images
What are the main features of eyesight at 5-8 months?
Good colour vision by 5 months
Can crawl and reach for objects at
What are the main features of eyesight at 9-12 months?
Can spot small (2-3mm) object nearby
Watched faces and can imitate expressions
Searches for hidden objects after observing hiding
What are the main features of eyesight at 24 months?
Complete myelinisation of the optic nerve - acuity is normal
What are the main features of eyesight at 2-5 years?
Brain functions nearly adult
Analysis of complex visual scenes
What are the main features of eyesight at 3 years?
Retinal tissue is mature
Child can do puzzles, draw a crude circle and but 2.5cm pegs into holes
Define blindness
So blind that they cannot do any work for which eyesight is essential
What are the most common forms of visual impairment
Cataract
Uncorrected refractive issues
What are the consequences of visual impairment?
3x more likely to be unemployed involved in a motor accident suffer from mental illness more likely to have a fall whilst walking
Where do 60% of the world’s blind live?
subsaharan africa, china and india
How does trachoma lead to blindness?
Active trachoma Repeated infections lead to scarring of the eyelid Trichiasis Corneal opacity Blindness
How can avoidable causes of blindness be eliminated?
SAFE
Surgery
Antibiotics
Face Washing
Education and Environmental
What us the most common cause of visual impairment in the UK?
Age related macular degeneration
Can be dry or wet
Visual loss accelerated in wet AMD
How to avoid wet AMD?
Avoid cigarettes
Good nutrition and cardiovascular health
Anti-VEGF injection
How do we diagnose diabetic retinopathy?
Screening programme
How can diabetic retinopathy be partially controlled?
Good control - HbA1c
What is first line treatment for diabetic retinopathy?
Laser photocoagulation
BUT it is destructive
May stabilise but cannot restore vision
What is diabetic maculopathy?
Leakage and bleeding at the macula
Treated by anti-VEGF injection
What is glaucoma?
A progressive optic neuropathy characterised by typical optic disc changes and commensurate visual field defects
Why is glaucoma actively screened for?
50% undiagnosed
What is a cause of glaucoma?
Raised intra-ocular pressure
What is cataract?
Clouding of the lens
How are cataracts treated?
Intraocular lenses
What is Thyroid Eye Disease?
Most common in Graves hypothyroidism
What causes Thyroid eye disease?
Antibodies targeting antigens in the thyroid and orbit
- Insulin like growth factor 1 receptor Ab
- Thyroid stimulating hormone receptro TSHR Ab
What can cause a life and sight threatening emergency?
Temporal Arteritis
Oculomotor nerve palsy
What are the diagnosis criteria for temporal arteritis?
Age> 50
New headache
ESR > 50mm/h
Positive temporal artery biopsy
