Ophthalmology Flashcards
What are the main refractory surfaces of the eye?
Cornea and lens.
What are the visual milestones from birth-3 months?
Do not focus on targets further than 20-30cm away.
Only see high contrast, e.g. chequerboard, not colours.
Cannot move their eyes between the 2 images.
At 3 months, should be able to fix and follow.
*What are the visual milestones from 5-8 months?
Good colour vision by 5 months of age.
8 months old start crawling, reaches for objects.
What are the visual milestones from 9 months-1 year?
Visually spot a small (2-3mm) object nearby.
Watches faces and tries to imitate expressions.
Searches for hidden objects after observing the ‘hiding’.
*What are the visual milestones in the first 7 years?
By 2 years, complete myelinisation of the optic nerve is completed; acuity is normal.
2-5 years: brain functions nearly adult, basic sensory processing abilities; analysing complex visual scenes, specific objects and faces will occur later.
By 3 years: retinal tissue is mature, the child can complete a simple form board correctly (based on visual memory), do simple pushes, draw a crude circle and put 2.5cm pegs into holes.
By 5-7 years: the functional development of brain substrates for perception of complex visual scenes takes still longer.
*What is blindness?
So blind that they cannot do any work for which eyesight is essential.
What is visual impairment or partial sight?
A visual acuity from 3/60 to 6/60 with a full field.
Up to 6/24 with moderate restriction of visual field, opacities in the media or aphakia.
6/18 or better with a gross field defect (e.g. hemianopia) or a marked constriction of the field (e.g. glaucoma or retinitis pigmentosa).
*What are the leading causes of avoidable visual impairment worldwide?
Cataract.
Uncorrected refractive errors.
Glaucoma. Diabetic retinopathy. Childhood blindness. Age-related macular degeneration. Trachoma. Corneal opacities. Other causes.
*What are the leading causes of avoidable blindness worldwide?
Unoperated cataract.
Glaucoma.
Age-related macular degeneration. Corneal opacities. Childhood blindness. Uncorrected refractive error. Trachoma. Diabetic retinopathy. Other causes.
*What are the leading causes of blindness in the UK?
Degeneration macular and posterior pole. Glaucoma. Diabetic retinopathy. Multiple pathology. Optic atrophy. Cerebrovascular disease. Hereditary retinal disorders. Other conditions/ unknown.
What is wet AMD? aetiology, symptoms, findings, investigations, treatment, prevention.
Aetiology: Age related macular degeneration (AMD).
Symptoms: distortion, sudden vision loss.
Findings: blood at macula, scarring
Investigation: fluorescein angiography (FFA), OCT.
Treatment: intra-vitreal anti-VEGF, PDT.
Prevention: avoid cigarettes (active and passive smoking); good nutrition, cardiovascular health.
What is diabetic retinopathy?
Microvascular complication of diabetes.
Vision loss if complications of proliferative disease.
Partial prevention if control good: HbA1c (DCCT); BP, lipids, proteinuria (T-2 WESDR UKPDS).
First line treatment by laser photocoagulation, but laser is destructive- may stabilise but cannot restore vision.
What is glaucoma?
A progressive optic neuropathy characterised by typical optic disc changes and commensurate visual field defects.
Raised intraocular pressure.
Irreversible
What is the epidemiology of glaucoma?
2nd leading cause of blindness UK and globally.
Irreversible.
Blind registration statistics Ireland: glaucoma accounts for 16% of blind.
2% population over 50y/o.
Incidence 0.2% per year.
5-10% go blind.
Overall UK prevalence ~1-2%.
Up to 75 patients per GP list.
Only 50% of glaucoma patients diagnosed.
Screening: glaucoma is more common in certain well defined groups.
What does misalignment of visual axes lead to?
Double vision- adults, or suppression of second image/lazy eye- in children
