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Ophthalmology > Gradual loss of vision > Flashcards

Gradual loss of vision Flashcards

1
Q

causes of gradual loss of vision

A

cataract, macular degeneration, glaucoma, diabetic retinopathy, hypertension, optic atrophy, slow retinal detachment

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2
Q

what is the main cause of blindness

A

age related macular degeneration

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3
Q

what part of the vision is lost in age related macular degeneration

A

central vision (peripheral is maintained)

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4
Q

dry age related macular degeneration

A

mainly drusen and degenerative changes at macula. slow progression

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5
Q

wet age related macular degeneration

A

new vessels grow from choroid into retina and leak. deteriorates quickly

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6
Q

features age related macular degeneration

A

progressive gradual loss of central vision- difficulty reading and recognising distant objects. peripheral vision maintained so can navigate. pupil reactions normal

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7
Q

what can wet age related macular degeneration present like

A

vision deteriorates quickly. distorted images- straight lines wavy.

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8
Q

when are drusen usually first deposited

A

after age 45 years, but asymptomatic then

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9
Q

what investigation can be done age related macular degeneration if suspecting choroidal neovascularisation

A

fundus fluorescin angiogram. optical coherence tomography (OCT)

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10
Q

management age related macular degeneration

A

intravitreal VEGF inhibitors- bevacizumab and ranibizumab (wet); laser photocoagulation(wet); intravitrealsteroids; antioxidants and vitamins

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11
Q

pathogenesis open angle glaucoma

A

aqueous humour drains through trabecular meshwork in angle between cornea and iris. over time it undergoes morphological change. rise in IOP transmitted to optic disc where nerve fibre damage occurs

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12
Q

risk factors open angle glaucoma

A

genetic, increasing age, DM, myopia, black race, thin cornea

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13
Q

features open angle glaucoma

A

no symptoms until so advanced that central vision is threatened, no headache, eye pain, loss acuity

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14
Q

signs open angle glaucoma

A

increased IOP, optic disc cupping, peripheral visual field loss

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15
Q

optic disc exam open angle glaucoma

A

rim becomes pale and cup enlarges. cup:disc ratio

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16
Q

what cup:disc ratio suggests glaucoma

A

0.6. also asymmetry between the eyes of 0.2 is significant. (normal 0.4-0.7)

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17
Q

how to examine optic disc

A

stereoscopic viewing through a dilated pupil. OCT optical coherence tomography

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18
Q

visual field defect open angle glaucoma

A

central scotoma

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19
Q

treatment open angle glaucoma

A

prostaglandin analogues- latanoprost, travoprost- incr aqueous outflow through uveoscleral route rather than trabecular meshwork; B blockers to reduce production humour- timolol, betaxolol; alpha adrenergic agonists- brimonidine; carbonic anhydrase inhibitors; miotics- pilocarpine; sympathomimetics

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20
Q

surgery option in open angle glaucoma

A

trabeculectomy

21
Q

which fields are lost first inopen angle glaucoma

A

nasal and superior fields, temporal are lost last

22
Q

what is optic disc cupping

A

loss of disc substance. if >0.9 cup:disc ratio then severe cupping

23
Q

what is a cataract

A

opacity in the lens

24
Q

what happens to the red reflex in cataract

A

still present in an immature cataract, but absent in dense cataract

25
Q

what morphological variants can occur with cataract

A

nuclear sclerosis- common in old age, subcapsular- shallow opacification can be from steroid use; cortical; dot opacities

26
Q

pre senile cataract causes

A

diabetes, corticosteroid therapy, atopy, galactosaemia, hypocalcaemia, dystrophia myotonica

27
Q

causes of congenital cataract

A

1/3- autosomal dominant. 1/3- birth trauma or maternal infection- rubella, toxoplasmosis.

28
Q

presentation cataract

A

blurred vision, unilateral often unnoticed but loss of stereopsis affects distance judgment. bilat causes loss of vision, dazzle, monocular diplopia

29
Q

how may cataract present in children

A

squint, loss of binocular function, white pupil, nystagmus

30
Q

treatment of cataract

A

prior to surgery- ocular biometry. surgery- lens extracted and another lens inserted- Perspex, acrylic, silicon. antibiotic and anti-inflammatory drops post op

31
Q

post op complications after cataract

A

posterior capsule thickening, astigmatism, eye irritation, rare- VH, retinal detachment, glaucoma

32
Q

prevention cataract

A

photoprotection- sunglasses. UV-B. decrease oxidative stress

33
Q

signs in optic atrophy

A

discs are pale. may be from incr IOP or retinal damage (choroiditis, retinitis pigmentosa); or ischaemia

34
Q

causative toxins optic atrophy

A

tobacco, methanol, lead, arsenic, quinine, carbon bisulfide

35
Q

causes optic atrophy

A

toxins, lebers optic atrophy, MS, syphilis, tumours

36
Q

what is visual loss usually due to in diabetic retinopathy

A

vitreous haemorrhage, maculopathy

37
Q

what happens in diabetic retinopathy

A

accelerates formation age related cataract, causes ocular ischaemia-new blood vessels to form on iris leads to glaucoma if prevents drainage of the aqueous fluid

38
Q

classification diabetic retinopathy

A

background, pre proliferative and proliferative

39
Q

what does vascular occlusion lead to diabetic retinopathy

A

ischaemia and new vessels forming in retina, otic disc, iris- proliferative retinopathy

40
Q

features of background retinopathy

A

microaneurysms, dot and blot haemorrhages, exudates

41
Q

features pre proliferative

A

cotton wool spots, venous beading, exudates

42
Q

features proliferative

A

new vessels at the disc, and elsewhere. cotton wool spots, flame shaped haemorrhages- ruptured microaneurysms

43
Q

what do cotton wool spots show

A

ischaemic nerve fibres

44
Q

what is maculopathy

A

leakage from vessels close to the macule cause oedema and threaten vision

45
Q

treatment diabetic retinopathy

A

good control diabetes, keep BP

46
Q

what can you treat diabetic macular oedema with

A

intravitreal triamcinolone and anti VEGF drugs

47
Q

what can be a complication in diabetic retinopathy

A

vitreous haemorrhage

48
Q

what factors can accelerate retinopathy

A

pregnancy, dylipidaemia, icr bp, renal disease, smoking, anaemia

Ophthalmology (6 decks)

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