Ophthalmology Flashcards
What are the 3 layers of the eyeball?
1) Outer fibrous (cornea + sclera)
2) Vascular (uvea): iris + pupil + ciliary body + choroid
3) Inner neural layer (retina: rods + cones)
What is the blind spot?
Site where optic nerve exits back of eyeball. There are no photoreceptors here, hence it is a ‘blind’ spot
Define amblyopia
Impaired vision despite a structurally normal eye, due to abnormal visual development. Also known as a ‘lazy eye’
Myopia is (near/far)-sightedness and occurs due to a (short/long) eyeball axial length. It requires a (positive/ negative) and (convex/ concave) lens to correct the refractive error.
Near-sightedness
Long eyeball
Negative (concave) lens
Hyperopia is (near/far)-sightedness and occurs due to a (short/long) eyeball. It requires a (positive/ negative) and (convex/ concave) lens to correct the refractive error.
Far-sightedness
Short eyeball
Positive (convex) lens
OD stands for ______ and indicates the (right/ left) eye whilst OS stands for _______ and indicates the (right/ left) eye
Oculus dexter = right eye
Oculus sinister = left eye
The gold standard of measuring intraocular pressure (IOP) is ________
Goldmann tomometry
The gold standard of angle measurement is ________
Gonioscopy
True or false: cataracts will cause a RAPD
False
Cocaine will cause pupil (constriction/ dilatation) and opioids will cause pupil (constriction/ dilatation)
Cocaine - dilatation
Opioids - constriction
In an abducted position, which muscle is responsible for controlling upwards movement?
Superior rectus
Which 2-3 eye drops are used to dilate the pupil? How does each act?
1) Local anaesthetic (Proparacaine i.e. Alcaine)
2) Tropicamide (Mydriacyl) - anticholinergic, causes relaxation of circular sphincter muscle
3) ± phenylephrine (Minims) - sympathomimetic, causes contraction of radial dilator muscle
A pale optic disc may be a sign of ______ or _____
Optic neuritis or ischaemia
Cotton wool spots may be a sign of _____ or ______
Diabetics retinopathy or hypertensive retinopathy
A cherry red spot is a sign of _____
Central retinal artery occlusion
AV nipping and silver wiring are signs of _______. What is the mechanism?
Hypertensive retinopathy
AV nipping due to small arteriole crossing small venule & causing compression due to high pressures
Silver wiring due to vessel wall hyperplasia & thickening
(Myopia/ hyperopia) is a risk factor for retinal detachment?
Myopia (esp the high type)
The risk is 5-6X greater with high myopia comparedto low mypopia. High myopic eyes are elongated, which means the retina is more stretched and therefore prone to peripheral tears.
Gas bubbles inserted into the vitreous cavity will be slowly absorbed over _____ weeks
2-6 weeks
True or false: an epiretinal membrane will usually cause metamorphopsia
True
___% of epiretinal membranes are progressive
20%
Homocystinuria & Marfan’s syndromes are associated with what ocular complications (2)?
Lens subluxation and retinal degeneration
Ankylosing spondylitis is most commonly associated with which eye disease?
Acute iritis
What is keratoconjunctivitis sicca more commonly known as?
Dry eyes
List 6 complications of cataract surgery
Posterior capsular opacification (10%) Endophthalmitis Corneal decompensation Dropped nucleus Retinal detachment Macular oedema
What is the cause of a chalazion and stye, respectively?
Chalazion = blocked meibomian gland forming a cyst. PAINLESS firm nodule
Stye = blocked eyelash hair follicle (sebaceous gland). PAINFUL small red nodule
Both have similar appearances
The central retinal artery comes off what vessel?
Ophthalmic artery (1st branch of internal carotid artery)
Conjugate eye movements are controlled by _____________
The medial longitudinal fasciculus (MFL)
The dilator pupillae is _____ (structure) smooth muscle and supplied by the SNS/PNS.
The sphincter pupillae is _____ (structure) smooth muscle supplied by the SNS/PNS
Dilator - radial SM, supplied by SNS
Sphincter - circular SM, supplied by PNS
How many layers does the retina have?
10
Aqueous humor from the anterior cavity of the eye drains out through the Canal of _______
Schlemm
What is the most common primary orbital malignancy in children?
Rhabdomyosarcoma
What is dacryocystitis? How is it treated (in adults and children)
Infection or inflammation of the nasolacrimal sac usually secondary to nasolacrimal duct blockage.
In children it usually spontaneously resolves, in adults it usually requires surgery
What are 2 causes of leukocoria in an infant?
Congenital cataract
Retinoblastoma
**MUST NOT MISS CONDITION
A 3rd cranial nerve palsy can be associated with what vascular lesion?
Posterior communicating artery aneurysm
What is the most common intraocular malignancy in adults?
Choroidal melanoma
Retinitis pigmentosa is an inherited retinal condition characterised by _____
Painless, progressive vision loss beginning with night blindness (rods affected first) and loss of peripheral vision. Usually bilateral
Retinitis pigmentosa mostly (and initially) affects which photoreceptors?
Rods
A stye is also known as a ____
Hordeolum
Allergic conjunctivitis is typically (uni/ bilateral) and characterised by _____
Bilateral
Cobblestone appearance d/t conjunctival papillae
What eye conditions are associated with albinism? (4)
1) Poor vision
2) Nystagmus
3) Strabismus
4) Hypoplastic/ under-developed maculae, fovea blunting
Also optic disc atrophy , photophobia
What are 3 causes of proptosis?
1) Graves’ thyroid disease
2) Tumours (rhabdomyosarcoma, optic nerve glioma, neurofibroma, neuroblastoma, lymphoma)
3) Papilloedema
Herpes zoster ophthalmicus will show up as a _____ corneal ulcer with fluorescein stain
Pseudodendritiform (no terminal end bulbs)
What virus typically causes viral conjunctivitis?
Adenovirus
True or false: conjunctivitis usually impairs vision
False - usually normal vision with clear cornea unless severe
In neonates, (Chlamydial or gonorrhoeal) infection produces a more severe conjunctivitis?
Gonorrhoea (risk of perforation of cornea)
_____ is characterised by severe eye pain and deep violaceous injections. 50% of cases are associated with systemic disease
Scleritis
What are the most common causes of endophthalmitis? (2)
Intraocular surgery (esp cataracts) Penetrating trauma
Topical steroids can be given for Herpes (simplex or zoster)?
Zoster
DO NOT GIVE STEROIDS TO HERPES SIMPLEX WITH DENDRITIC ULCER
Which type of keratitis is associated with a ‘ring ulcer’
Acanthamoeba (protozoan)
What organisms typically cause dacryocystitis in a) children and b) adults
a) Staph aureus, ß-haemolytic strep
b) S. epidermidis, S. aureus
What eye complication is associated with toxoplasmosis?
Chorioretinitis
Hyperopia predisposes to ____
Acute angle closure glaucoma
____ (type of refractive state) is normal in neonates
Hyperopia (small eyeball)
What is the normal optic cup to disc ratio
0.3
List some risk factors for cataracts
Acquired
- Older age
- Smoking
- EtOH
- Excessive sunlight
- Prolonged corticosteroids
- Diabetes
- Trauma
- Infection
Congenital
- Classic galactosaemia
- Galactokinase deficiency
- Trisomy 13, 18, 21
- ToRCHS infections
- Marfan syndrome
- Alport syndrome
- NF2
- Myotonic dystrophy
With regard to CNIII damage:
Motor output has fibres (centrally/ peripherally) is primarily affected by _______
Parasympathetic output has fibres (centrally/ peripherally) that are first affected by _____
Motor output - central fibres, affected by vascular disease (e.g. diabetes, HTN) d/t poor diffusion of O2 and nutrients
PNS - peripheral fibres, affected by compression (e.g. PComm aneurysm, uncal herniation, tumour)
In glaucoma, intraocular pressure is >___ mmHg
> 21
What is the pharmacological management for glaucoma?
1) Increase aqueous fluid outflow with pilocarpine (muscarinic agonist) or PG analogues
2) Decrease aqueous humor production with ß-blockers or CAi (acetazolammide aka Diamox)
3) Combined: alpha-AR agonists
In dry ARMD (soft/ hard) drusen have a higher risk
Soft
What visual field defect is classically present in glaucoma?
Superior actuate defect
Myasthenia gravis can cause what eyelid condition
Ptosis
Horner’s syndrome - What underlying cause do you need to rule out in children and adults respectively?
Children - neuroblastoma
Adults - carotid artery dissection
The ‘morning glory optic disc’ is associated with _______
Basal encephalocele
