Ophthalmology Flashcards
What is the circulatory pathway of aqueous humour?
Produced by the ciliary body, circulates within the anterior chamber, and is filtered back into venous system through trabecular meshwork
Where is central vision best?
Fovea, the central most part of the macula, which is the central retina
Where does the optic nerve enter the retina?
Optic disc
Components of an eye exam
History Exam: - general inspection - visual acuity (best corrected) - Slit lamp (anterior segment of eye) - Pupils - Fundoscopy - Other tests (H test, CT scan, orbital x-ray, bloods)
Characteristic signs of iritis
Pain and photophobia
Red eye with CILIARY FLUSH
Slight blurred vision
Pain in contralateral eye on direct light exposure
Irregular pupil with synaechiae
Pupil may not be reactive to light
Characteristic signs of acute angle closure glaucoma
Mid-dilated, very poorly responsive to light
What does fluorescein stain check?
Corneal pathology
Most common causes of chronic vision loss
Refractive error Lens: Cataract Macula: AMD Retinal: Diabetic retinopathy Optic nerve: Glaucoma (open-angle)
Common causes of acute vision loss
Transient - Amaurosis Fugax
Persistent:
- Vaso-occlusive: central retinal artery/vein occlusion
- Optic nerve: Optic neuritis OR giant cell arteritis
- Retinal detachment
Causes of BILATERAL vision loss
Central:
- Pituitary apoplexy
- Stroke
Ocular:
- Quinine or methanol poisoning
Causes of unilateral vision loss if eye is:
- Sore or red
- Not sore or red: flashes or floaters vs. none
Sore or red (pathology in anterior chamber)
- ACUTE IRITIS
- CLOSED ANGLE GLAUCOMA
Not sore/red
Flashes or floaters:
- RETINAL DETACHMENT
- VITREOUS HAEMORRHAGE
No floaters
- CRA occlusion
- CRV occlusion
- Vasospasm
Visual field distortion
- AMD
Swollen optic disk
- Optic neuritis
- Giant cell arteritis
- Anterior ischaemic optic neuropathy
Causes of vasospasm that can cause visual loss
Migraine
SA haemorrhage
Hypertensive crisis
Where is the lesion:
- homonymous hemianopia
- bitemporal hemianopia
Homonymous: behind optic chasm
Bitemporal: at optic chasm (pituitary tumour)
Myopia vs hyperopia: what are they and where are light rays focussed in each case?
Myopia - short sighted; light rays focused anterior to fovea
Hyperopia - far sighted; light rays focussed posterior to fovea
What is presbyopia and what causes it?
Age-related loss of near vision (onset around 40s)
Due to diminished accomodation power
Diseases of refractive error and treatment
Hyperopia
Myopia
Astigmatism
Presbyopia
Correct w glasses/ contact lenses
LASIK - laser surgery alters corneal surface
Cataract - what is it?
- Causes?
- Clinical picture?
- Treatment?
Opacification of lense
Causes: age-related; steroids; diabetes; previous inflammation or scarring (surgery, trauma)
Clinical picture:
Bilateral, asymmetric, slowly progressive
SX: Blurred vision with glare especially at night, difficulty driving
Signs: Impaired VA, clouding of sense on slit lamp exam (decr red light reflex, hard to see optic disk and retina)
TX:
Glasses + surgery
What is a chalazion?
what is it often associated with?
ABSCESS beneath lid resulting from focal noninfectious blockage of meibomian gland -> non-tender lump in eyelid
Assoc w Rosacea
Non-tender swelling of lid
What is a hordeolum ?
Aetiology?
Abscess at corner of eye, can be internal (on conjunctival side of eyelid) or external (=sty)
Painful focal lid erythema often accompanied by blepharitis
Staph aureus infection commonly
What common viral infection can spread to the eye?
how do you investigate for it?
Treatment?
HSV infection of trigeminal nerve can spread to eye, causing keratitis, uveitis, scleritis, retinitis
Fluroscene stain -> classic dendritic ulcer with BULB end
Antivirals - DO NOT give steroids
What is blepharitis and what causes it?
Clogging of meibomian glands within tarsal plate, leading to chronic irritation and inflammation of eyelid
-> dry, watery, itchy eyes
How do you treat corneal abrasions and ulcers?
Abrasion: lubrication and prophylactic erythromycin
Small ulcers: erythromycin
Large ulcers >3mm: MCS (sensitivities) and vancomycin
Different types of conjunctivitis
Viral: watery discharge, swollen pre-auricular nodes
- most common form in adults
- adenovirus and rhinovirus are common causes (HSV is more severe)
- recent flu-like illness
TX: self-limiting; good heigine to limit spread
Bacterial: mucus discharge
- most common form in kids
- follicles and papilla on inner surface of lid
- treat with erythromycin gel
Allergic: itchy, watery, chemosis (swelling of sclera)
+/- dark area underneath eyes
- antihistamines
What is endopthalmitis?
Severe infection WITHIN the eye, often post-surgical procedures
With hypopion (pus forms fluid level at bottom of iris)
Needs aggressive treatment -> vitrectomy to eject pus from eye -> send for MCS -> antibiotics
What infective agents cause conjunctivitis?
Staph aureus, strep in kids
H influenza in adults
Neisseria gonorrhoea in sexually active adults (needs urgent referral because sigh threatening)
What is a hyphaemia?
Blood in anterior chamber of eye, forms fluid level at bottom of iris
Requires urgent ophthalmologist referral
what are the 2 broad categories of causes/risk factors for scleritis?
Autoimmune
- RA, UC, SLE, ankylosing spondylitis, psoriatic arthritis, Wegener’s granulomatosis
Granulomatous disease
- Tb, syphilis, sarcoid, leprosy
Clinical presentation of scleritis
TX?
Red/purple discolouration of sclera and conjunctivae
Ocular pain that is tender to palpation
Photophobia
TX: NSAIDs and systemic corticosteroids
CN3 palsy
- causes
- presentation
Causes
- Vasculitic (HTN, DM) - pupil sparing
- Aneurysm/tumours - pupil dilated
Presentation:
- Eye is down and out
- Ptosis
- If pupil is dilated, suspect aneurysmal cause
CN6 palsy
- causes
- presentation
Causes
- Vasculitic
- Incr ICP/Idiopathic intracranial HTN
Presentation:
- Cross eyed
- Double vision when looking towards affected side
- bilateral papilloedema if Incr ICP
CN4 palsy
- causes
- presentation
Causes:
- Vasculitis
- Trauma
- Congenital
- Tumour
Presentation
- Hypertropia
- Head tilts away from affected side (to offset extortion)
- Double vision when READING or walking down stairs
- eye shoots up when looking towards affected side
Neovascular vs non-neovascular AMD
Wet/ Neovascular/exudative: - Break in the Brux membrane (layer between PRs and choroid) allows choroidal neovascularisation under retina, leading to QUICK and permanent vision loss. Wet because vessels can bleed.
Dry/non-neovacular/non-exudative
- ~90 of AMD
- ‘Drusen’ on ophthalmoscopy are small deposits in the macula
- HTN is RF for progression of dry to wet AMD
Risk factors for AMD
Old age
Family HX
Smoking HTN predicts progression from wet to dry
Clinical picture of AMD
- SX and signs
- Fundoscopy
Blurred central vision
Metamorphopsia: distortion of straight lines centrally (occurs early)
Scotoma (blind spots) with progression
No pain/redness
Peripheral vision intact
Fundoscopy:
- Dry: druse deposits
- Wet: choroidal haemmhorage
Treatment for wet and dry AMD
Dry: antioxidants, zinc, vitamin C and E and carotenoid supplements
HTN control, stop smoking
Wet:
- anti VEGF +/- IV steroids or laser therapy
- laser photocoagulation
Features of Diabetic retinopathy: pre-proliferative and prolferative/end-stage
Pre-proliferative
- cotton wool spots
- hard exudates
- blot haemorrhages
- micro aneurysms
- venous beading
- retinal oedema
Proliferative
- Neovascularisation
- Vitreous haemorrhage
- Angle closure neovascularisation glaucoma
End-stage
- vessel fibrosis and retinal detachment
treatment for Diabetic retinopathy
Diabetic, HTN, hyperlipidaemia control
Grid or pan-retinal laser photocoagulation
Intra-vitreal VEGF antagonist injections
Surgical repair if vitreous haemorrhage or retinal detachment
Primary chronic open angle glaucoma: what is a characteristic feature?
What is the underlying pathophys?
Slowly progressive optic neuropathy
Optic disc cupping
Due to excess glycosaminoglycan deposition in trabecular meshwork, blocking aqueous outflow -> incr IOP damages optic nerve fibres
Acute angle closure glaucoma
What is the underlying pathophys
aqueous cannot get through the space between the pupil and iris from the posterior chamber into anterior chamber, so pressure gradient forms within the posterior chamber, pushing the iris forwards and closing it to block off the entrance to the trabecular meshwork so aqueous cannot drain.
RF for open angle glaucoma
Genetic Incr age Family history Thin cornea African, latino ethnicity
RF for closed angle glaucoma
Asian
Small eyes, hyperopia
big cataracts
Shallow chamber
Clinical features of open angle glaucoma
- Sx and signs
- ophthalmoscopy findings
SX and signs:
Asymptomatic until late stage
Visual field is end-stage
- Initially upper arcuate scotoma
- progresses to full visual field loss with sparing of small central field +/- small temporal field
No eye pain or tenderness
Headache rare except when IOP is v high
Ophthalmoscopy:
- Enlarged cup: disc ratio (>=0.5)
- Elevated IOP
Treatment for chronic open angle glaucoma
Surgical
- Drainage trabeculectomy
- Laser trabeculoplasty
Medical
- PGE analogues
- Topical beta blockers
- Topical carbonic anhydrase inhibitors
- Adrenergic agonists
- Cholinergic agonists (pilocarpine)
Clinical features of acute closed angle glaucoma
Signs and SX
exam findings
Rapid elevation in IOP and ischaemic tissue damage resulting in:
- painful red eye
- photophobia
- haloes
- pain on eye movement
- watering of eye
- rapidly decreasing visual acuity
+/- headache, nausea and vomiting
Exam:
- red eye
- cloudy cornea
- oval, fixed, dilated pupil
Treatment for acute closed angle glaucoma
Medical:
IV Acetazolamide (carbonic anhydrase inhibitor)
+ PO topical pilocarpine (cholinergic agonist)
+ PO beta blockers
Surgical:
Laser iridotomy in BOHT eyes (prophylactic in opposite eye)
Non-painful diffuse red eye conditions
With eyelid involvement
without
With eyelid involvement:
- Blepharitis (Can also be painful)
- Ectropion
- Trichiasis
- Eyelid lesion
Without - conjunctivitis (also painful)
PainLESS LOCALISED red eye conditions
Localised:
- pterygium
- corneal foreign body (can also be painful)
- ocular trauma (can also be painful)
- subconjunctival haemmhorage
What is blepharitis?
Noninfectious lid margin inflammation with chronic redness +/- crusting
(like chalazion but no cyst formation)
+/- bacterial superinfection
What is ectropion?
Lid turns outwards with exposure of conjunctival sacs
What do you call the condition when the eyelashes are turned inwards?
What commonly causes this?
Trichiasis
Caused by trachoma (infectious disease caused by bacterium Chlamydia trachoma’s, common in children with poor sanitation)
What is pterygium?
Flesh grows over the sclera. Benign. May become inflamed and painful.
Needs lubrication and sunglasses w non-urgent referral.
What is the cause of a painless, unilateral, well circumscribed bloody red patch on eyeball
With no other visual abnormalities
Subconjunctival haemorrhage
what is the difference between episcleritis and scleritis?
Episcleritis blanches when injected w 10% phenylephrine ophthalmic drops, but NOT in scleritis
Scleritis generally more red and painful with tenderness to palpation.
Episcleritis generally NOT painful and is self-resolving.
Both red but have no photophobia and normal vision and pupil.
What is episcleritis usually caused by?
Autoimmune conditions
- RA
- SLE
- graves
- ankylosing spondylitis
- IBD
- psoriatic arthritis
Treatment of episcleritis
Self limiting
Hydration
Topical prednisilone if prolonged steroids +/- systemic NSAID/CS
Workup for autoimmune diseases
What usually causes bacterial/acanthamoebal ulcer? (epithelial keratitis)
from unclean contacts
What is the common cause of keratitis that needs urgent opthal referral?
TX?
HSV-1
TX: trifluoridine eye drops with antiviral therapy
AVOID topical steroids! makes it worse!
Signs of hypertensive retinopathy
Grade 1: copper wiring
Grade 2
As grade 1 + Irregularly located, tight constrictions - Known as AV nicking or AV nipping - Salu’s Sign
Grade 3
As grade 2 + cotton wool spots and flame-hemorrhages
Grade 4
As grade 3 + optic disc swelling + macular star
