Ophthalmology Flashcards
4 types of change in appearance of the eyelid
Ptosis
Swelling
Entropion (turning in)
Ectropion (turning out)
Which muscles are innervated by CN3?
Medial rectus
Superior rectus
Inferior rectus
Inferior oblique
What is the appearance of the eye due to 3rd nerve palsy?
Down and out
Ptosis
Fixed dilated pupil
What is strabismus
Misalignment of the eyes (squint)
What vasculitis is important to exclude in transient loss of vision?
Giant cell arteritis
What is the management of giant cell arteritis?
Steroids
Temporal artery biopsy
Very high inflammatory markers
What common eye condition causes loss of peripheral vision?
Glaucoma
5 causes of gradual vision loss?
Glaucoma Cataracts Macular degeneration Diabetic retinopathy Increased intracranial pressure
What is phacoemulsification?
Fragmentation of lens fibres using ultrasound.
What is the most common type of glaucoma?
Chronic open angle glaucoma
What does the ‘angle’ refer to in glaucoma?
The angle between the posterior surface of the cornea and the anterior surface of the iris (iridocorneal angle)
What produces the aqueous in the eye?
Ciliary body
Where does aqueous leave the eye?
- Trabecular meshwork in the angle
- Enters the episcleral veins
What is normal intraocular pressure?
<21mmHg
What is chronic open angle glaucoma?
Optic neuropathy where by there is an increase in IOP >21 mmHg, enlargement of the optic disc cup (loss of neurones) and progressive loss of visual field
What sort of vision is characteristic of open-angle glaucoma?
Tunnel vision (peripheral visual loss)
Which visual fields do arcuate scotomas begin in?
Superior or inferior
What is the 1st line treatment of glaucoma?
Topical ophthalmic prostaglandins eg lantanoprost
What classes of medications are used to treat glaucoma other than prostaglandins?
Beta-blockers eg timolol
Carbonic anhydrase inhibitors eg dorzolamide
Alpha-2 adrenergic agonists eg brimonidine
What surgical treatment is there for glaucoma?
Laser trabeculoplasty
At what part of the retina is visual acuity highest?
Macula
Where is the macula located?
3mm temporal to the optic disc
What are the 2 types of photoreceptors? Where are they located? What are they responsible for?
Rods - Peripheral vision, vision at low light levels (scotopic), not present in fovea centralis of macula
Cones - Central vision, high spatial acuity, vision at higher light levels (photopic vision). Found in the fovea centralis of macula
What 3 things does good visual acuity depend upon?
- Functioning photoreceptors
- Healthy retinal pigment epithelium
- Perfusion of the capillary layer of the choroid (the choriocapillaris)
What are drusen?
Yellow fatty lipid deposits (waste material from photoreceptors) which accumulates below the retinal pigment epithelium
What is the most common type of age related macular degeneration?
Dry AMD
What is the visual loss seen in dry AMD?
Central scotoma with good peripheral vision
What is the pathology of dry AMD?
Atrophy of the retinal pigment epithelium, choroid and photoreceptors in retina
What can be seen with opthalmoscope in patient with dry AMD?
Drusen and retinal pigment clumping /atrophy
What can be seen with opthalmoscope in a patient with wet AMD?
Macular drusen
Choroidal neovascular membrane - loads of vessels
Subrential or intraretinal haemorrhage
What percentage of AMD cases are wet AMD?
10%
What is the pathology of wet AMD?
New vessels in choroid are formed (choroidal neovascularisation)
New vessels leak fluids, lipids and blood into layers behind retina
Localised retinal detachment
Retinal scarring
Visual loss in wet AMD?
Blurred vision
Metamorphopsia - straight lines appear wavy
Poor night vision
Central visual loss
What does myopia mean? What type of lens is required to correct it?
Short sighted
Concave
What does hyperopia mean? What type of lens is required to correct it?
Long sighted
Convex
3 features of glaucoma
loss of visual fields
cupping of optic disc
intra ocular hypertension
Side effect of carbonic anhydrase?
Fatigue, dyspepsia
Pins and needles
What can make the intraocular pressure appear higher than it is?
Thick central cornea - some people are born with this
Treatment options for wet AMD?
Laser photocoagulation
Intravitreal anti-VEGF
What is the treatment of early dry AMD?
Nutritional therapy - high in antioxidants, carotenoids and omega 3 fatty acids.
What can be seen with opthalmoscope in a patient with diabetic retinopathy?
Microaneurysms cause weak cap walls which leak (hard exudates) and bleed (haemorrhages) causing ichaemic infarcts (Cotton wool spots) and neovascularisation
Differential diagnoses for causes of microaneurysms?
Diabetes
Retinal vein occlusion
Ocular ischaemia
What are the classifications of diabetic retinopathy in the UK?
Background
Background/preproliferative
Preproliferative
Proliferative
What is the management of background diabetic retinopathy?
No treatment as not currently sight threatening
Annual review
Investigation of other organs that are affected by diabetes.
What area does the macular cover?
A circle whose radius is the distance from the foveola to the temporal edge of the optic disc.
What is diabetic maculopathy and are the causes of visual loss of diabetic maculopathy?
Leaky or blocked vessels in macula
Macular oedema
Foveal ischaemia
Foveal haemorrhage