Opthalmology Flashcards
(143 cards)
Opthalmoscopy: what must you do first.
- what kind of agent
- warning
- C.I.
Dilate the pupil with parasympathomimetic (Tropicamide - lasts for 20 min - 12h)
Warn about driving as affects ciliary muscles inhibiting accommodation for near vision
Head injury (require pupil reflex)
Risk of closed angle glaucoma
4 C of normal Optic disc
Colour - yellow/orange
Contour - well defined, flat
Cup - small depression in centre of optic disc. less than 0.5 of disc diameter. No vessels or nerve fibres
Circulation - not tortuous, not attenuated (reduced)
What is red reflex
reflection from orange retina
Sign of cataract or central tumour
Pale disc?
optic atrophy - prev damage to nerve
Elevated/swollen disc
papilloedema
Large cup
If over 50% of dis diameter -> chronic glaucoma
Attenuated (reduced vessels)
Central retinal artery occlusion
What is the optic disc?
The blind spot.
This is point of entry of BV and Optic nerve
What is Macula and Fovea
Area where visual acuity is the highest. Just temporal to Optic disc. No vessels.
Centre is Fovea - Just Cone (colour and acuity) receptors
Retina
- What
- abnormal signs
Layer at the back of eyeball with photoreceptors
Haemorrhages, Exudates, Drusen (lipid deposits), Scarring, Retinitis Pigmentosa (loss of photoreceptors - black deposits)
Signs of vascular disease in Retina
Flame haemorrhages: superficial (Retinal vein occlusion)
Blot haemorrhages: deeper (Diabetic)
Dot haemorrhage: micro aneurysms (Diabetic)
Preretinal (boat shaped) haemorrhages (Diabetic, SAH)
Hard Vs Soft exudate
Hard (true exudate) = leakage of fluid into retina
Soft = micro infarcts & cotton wool spots (fluffy/white)
What are drusen
Lipid deposits - Pale, Round, Grey spots seen at the macula
Seen in elderly, age related macula degeneration
What is retinitis Pigmentosa?
What is seen
Inherited retinal degeneration, spidery black pigmentation in peripheral retina
Tunnel vision and night blindness
Scotoma (relative & absolute)
Quadra/Hemianopia
Scotoma = blind spot
- Relative = decrease
- Absolute = total
Quarter loss /
Half loss
What is meant my congruity?
How well formed the shape of the defect is. gets better closer to visual cortex
Bitemporal hemianopia
- Cause
- diagnosis
compression of the optic chiasm
upper more than lower = pituitary tumour
lower more than upper = craniopharyngioma
Remember this as UP London City
Homonymous quadrantanopia
superior homonymous quadrantanopia = lesion in temporal lobe
inferior homonymous quadrantanopia = lesion in the parietal lobe
PITS - parietal inferior temporal superior
incongruous = optic tract
congruous = the optic radiation/cortex
Homonymous hemianopia (ssam e.g. left field in both eyes)
Brain lesion (Bleed or tumour) on Contralateral side to lesion
Central scotoma
Lesion in Optic nerve -> Optic neuritis
e.g demyelination in MS, toxins like methyl-alcohol
What is slit lamp for
Visualising Anterior segment of eye (vitreous body/lens)
Slit lamp signs
Flare = inflammation
Cells in vitreous (tobacco dust) = retinal tear
Outer layer of eye
Cornea over lens, sclera over rest
Anterior segment
- where
- what humor
Anterior to lens
Contains aqueous humor