Ophthalmology Flashcards
What are the chambers of the eye?
Anterior = cornea –> iris
Posterior = iris –> lens
Vitreous = lens –> back of eye
What is acute closed-angle glaucoma?
Angle of anterior chamber narrows acutely, causing sudden rise in IOP –> pupil becomes fixed and diated and axonal death occurs
How is aqueous humour produced and how does it normally drain?
- Produced by ciliary body into the posterior chamber, and flows through pupil into the anterior chamber
- Empties out via the drainage angle through the trabecular meshwork and through the canal of Schlemm into the aqueous veins
Predisposing factors to acute angle closure glaucoma?
- Shallow anterior chamber
- Thick lens
- Thin iris or ciliary bodies (e.g. pupil dilation at night)
- Hypermetropic eye (short axial eye length)
Primary and secondary angle closure?
Primary = occurs in patients with an anatomical predisposition
Secondary = Arises from pathological processes (e.g. traumatic haemorrhage pushing the posterior chamber forwards)
Peak incidence of acute angle closure?
40-60 years, more common in asia
What is open angle glaucoma?
Drainage system gradually becomes blocked –> outer rim atrophy of the optic nerve –> decreased peripheral vision then loss of central vision
Signs and symptoms of acute angle closure?
Symptoms
- Generally unwell; N+V
- Acute uniocular attack with headache and painful red eye,
- Blurred vision or haloes around lights at night
- Onset over hours-days
Signs
- Red eye; feels hard
Management of acute angle glaucoma?
General
- Examine visual fields, fundoscopy (nerve damage - “cupping”)
- Send IMMEDIATELY to eye unit for gonioscopy/tonometry
- Avoid eye patches or dark rooms (pupil dilation will worsen the angle closure)
Medical
- Beta-blockers (timolol) – suppresses aqueous humour production
- Acetazolamide IV (carbonic anhydrase inhibitor) – suppresses aqueous humour production
- Pilocarpine drops (cholinergic) – miosis will open up the drainage angle
- Analgesia/Antiemetics
Surgical
- Peripheral iridectomy (laser or surgery) – once IOP is controlled; a piece of iris is removed to allow aqueous to flow
What are cataracts? RIsk factors?
An opacity in the lens
- Age
- Genetic influence
- Occur early in DM
- Smoking, alcohol excess, sunlight exposure, trauma, radiotherapy, HIV
Symptoms of cataracts?
Blurred Vision
- If unilateral, often unnoticed, but loss of stereopsis affects distance judgement.
- If bilateral, gradual painless loss of vision +/- dazzle +/- monocular diplopia.
- Difficulty driving at night and haloes around street lamps.
How to diagnose a cataract?
Via retro-illumination of cataract using a handheld ophthalmoscope.
Management of cataracts?
Conservative
- Mydriatic drops or sunglasses –> if affecting lifestyle then surgery.
Surgical
- Day case using LA with small-incision surgery and pacoemulsion (breaks up the lens, then sucked out by cannula) + intraocular lens implant.
- Go home immediately, resume normal activities next day.
- Antibiotic + inflammatory drops for 3-6 weeks post-op
Risks of cataract surgery?
- 2% serious complications
- Dazzle/glare often remains
- Distance glasses often needed
Types of corneal ulcer?
- Bacterial
- Herpetic (dendritic)
- Fungal
- Protzoal
- Vasculitis (e.g. RA)
Presentation of corneal ulcer?
- Painful red eye
- Reduced visual acuity
- Photophobia
Pupil may be small due to reflexive miosis
Management of corneal ulcer?
General
- Refer to a specialist SAME DAY.
- Remove contact lenses
Medical
- Until culture results, alternate…
- Chloramphenicol drops (gram +ve)
- Ofloxacin drops (gram -ve) OR
- 0.3% cefuroxime and gentamicin drops
- Steroid drops once recovery starts.
What is this?
Hordeolum Externum (stye)
- Most common type
- Acute infection of lash follicle (in the skin) and always associated with
- Glands of Zeis (sebum-producing glands attached directly to lash follicles)
- Glands of Moll (sweat glands)
Second most common type of stye?
Hordeolum Internum
- Acute infection of a Meibomian gland situated within the tarsal plate.
- These point inwards, opening on conjunctiva.
- Causes less local reaction but leave a residual swelling (Chalazion) when they subside (treat with incision and curettage under LA
Presentation of a stye?
- Pain, redness and swelling of the lid margin. Whole of the lid may be affected.
- Swelling becomes localised, and a yellow, pus filled lesion may be seen near the lid margin (at the base of the effected eyelash) associated with an eyelid
- Localised tenderness on palpation of the eye lid
- Associated preseptal cellulites may be present
Management of a stye?
- Apply warm compress for 5-10 minutes several times each day until stye resolves.
- Topical antibiotic (fusidic acid) may prevent subsequent staphylococcal infection from a lash lower down
Types of conjunctivitis?
Non-Infectious
- Allergic (most common) - toxic, autoimmune, neoplastic
- Contact lens wearers may develop reaction
Infectious
- Non-herpetic viral (adenoviruses 80% - serous discharge)
- Bacterial (staphs, gonococcal - purulent discharge)
Presentation of conjunctivitis?
Symptoms
- Eyes itch, burn and lacrimate.
- Often bilateral with discharge sticking lids together
Signs
- Conjunctiva red and inflamed; hyperaemic vessels may be moved over the sclera by gentle pressure on the globe.
- Visual acuity, pupillary responses and corneal lustre unaffected
When are conjunctival cultures needed?
- Gonococcal/chlamydial infection suspected
- Neonatal conjunctivitis
- Recurrent disease not responding to therapy
Management of conjunctivitis?
Most cases are viral so only symptomatic treatment needed.
General
- Artificial tears
- Topical antihistamines (drops) – antivirals don’t help
- Education on face and hand washing as is v.contagious
Topical Abx (topical abx can reduce symptom duration and transmission risk - usually self-limiting 1-2 weeks)
- Chloramphenicol 0.5% drops (4-6 hourly)
- Start immediately if: sexual disease suspected, contact lens wearers or immunocompromised patients
Allergic
- Antihistamine drops
- Emedastine or Olopatadine
Management of ocular foreign body?
Investigations
- If metal foreign body suspected, X-ray orbit or consider orbital USS.
Management
- Expert advice
- LA in eye, remove manually
- Topical abx
- Eye covered with pad until epithelium recovers
What is this?
Black Eye
- Result of a haematoma within the soft tissue of the eyelids. Spread may occur down over the cheek.
- It usually resolves within 14 days
What is this?
Subconjunctival Haemorrhage
- Bright red patch under the conjunctiva following rupture of a small conjunctival vessel.
- Spontaneous, slight trauma, or result of local congestion due to coughing or sneezing
- Definable margin absent if secondary to trauma since the bleeding extends backwards into the orbit.
- No discharge, painless, normal acuity.
What is this?
Hyphaema
- Haemorrhage into the anterior chamber resulting from damage to blood vessels in the iris
- Clotting does not readily occur in aqueous humour à fluid level
- Obscures vision and impairs fundosocpy
- Disperses within a few days – can cause glaucoma requiring surgical evacuation
What is this?
Corneal Abrasion
- Superficial injury to corneal epithelium à pain, lacrimation, photophobia +/- ↓acuity
- Can result from scratches from sharp objects, contact lenses, trauma, chemical injury or previous corneal disease
-
Fluorescein drops + blue light to aid diagnosis (corneal lesions stain green)
- Ask contact lens wearers if they sleep with lenses in and how they are changed
- Topical antibiotics to prevent infection
What is the uvea? What is the anterior uvea?
Uvea = the pigmented part of the eye (iris, ciliary body, choroid)
Anterior uvea = iris + ciliary body
What is anterior uveitis associated with?
- Ankylosing spondylitis, Still’s disease
- Sarcoid, Behcet’s etc
- IBD, reactive arthritis
- Herpes, TB, syphilis, HIV
Presentation of anterior uveitis?
- Red eye –> starts with conjunctival injection around the junction of cornea and sclera and increased lacrimation
- Pain, blurred vision and photophobia.
- Pupil may be small, initially from iris spasm; later it may be irregular or dilate irregularly due to adhesions between lens and iris (synechiae)
- Onset over hours/days. Associated with headaches and features of systemic disease.
What is this?
Management?
Ectropion
- Lower lid eversion causing eye irritation, watering (drainage punctum malaligned) +/- exposure keratitis.
- Associated with old age and facial palsy.
- Management
- Plastic surgery
What is this?
Entropion
- Lid inturning; typically due to degeneration of lower lid fascial attachments and their muscles –> inturned eyelashes irritate the cornea
- Rare <40 yrs
Management
- Taping lower eyelids to cheek
- Botulinum toxin injection to lower lid
- Definitive management = surgery
What is blepharitis and how does it present?
Lid inflammation from staphs, seborrheic dermatitis or rosacea
- Eyes have burning itching red margins with scales on the lashes
Management
- Good eyelid hygeine
- Use cotton bud and baby shampoo diluted 1:10 with warm water and clean along lid margins 2x per day
What is episcleritis?
Inflammation below the conjunctiva often seen with an inflammatory nodule
Presentation of episcleritis?
- Acute onset
- Sclera look blue below a focal, cone-shaped wedge (thin edge towards pupil) or engorged vessels that can be moved over the area
- Dull ache; tender (especially over inflamed area)
- Acuity usually unaffected
Symptomatic relief - artifical tears, topical/systemic NSAIDs
What is scleritis?
- Generalised inflammation of the sclera itself with oedema of the conjuncitva, scleral thinning and vasculitic changes.
- 50% have systemic disease (RA, granulomatosis + polyangitis)
Presentation
- Constant severe dull ache which bores into the eye
- Ocular movements painful as muscles insert into sclera
- May present with headache and photophobia
- Engorged vessels can’t be moved over area as they are deeper
- Necrotising version can cause globe perforation
Management of scleritis?
Urgent referral
- NSAIDs/high dose steroids (non-necrotising anterior)
- Systemic immunosuppression (posterior)
- Surgical intervention (if necrotising)
Differentials for red eye?
ACASES (3 serious, 3 not)
- Acute glaucoma
- Conjunctivitis
- Anterior uveitis (iritis)
- Scleritis
- Episcleritis
- Subconjunctival haemorrhage
What is injection?
Prominence of vessels
- Conjunctival
- Cilliary (iris)
Pull down eyelid to differentiate
5 causes of acute visual disturbance?
- Posterior viterous detachment (PVD)
- Retinal detachment
- Amaurosis fugax (retinal vascular occlusion)
- Macular degeneration
- Optic neuritis
4 causes of gradual loss of vision?
- Refractive error (myopia, hypermetropia)
- Open angle glaucoma
- Macular degeneration
4 Fs of retinal detachment?
Floaters, flashes, field loss, fall in acuity
Medications for open angle glaucoma?
- Prostaglandin analogue - Increase uveoscleral outflow. Latanoprost, Bimatoprost, Travoprost. First-line treatment. SE: pigmentation, increase eyelash length, stinging, conjunctival injection.
- Beta-blockers - Reduce aqueous production. Timolol. Avoid in asthma, COPD, heart block
- Carbonic anhydrase inhibitors - Reduce aqueous production. Dorzolamide, brinzolamide. Usually in combination with beta-blocker
- Selective α2 receptor agonists - Reduce aqueous production. Brimonidine, Iopidine. Avoid with MOI. SE:lethargy, dry mouth & eyes, allergy
Surgery for closed angle glaucoma?
Trabeculoplasty (laser or surgery)
Wet/dry macular degeneration?
- Dry ARMD shows mainly drusen and degenerative changes at the macula. It progresses slowly.
- Wet ARMD occurs when aberrant vessels grow from the choroid into the neuro-sensory retina and leak. Vision deteriorates rapidly and distortion is a key feature. (Treatment available)
Symptoms
- Disturbed central vision – blurring, scotoma, distortion.
- Difficulty reading fine print
- Difficulty recognising faces
- Difficulty appreciating fine detail
Types of squint?
Concomitant (non-paralytic)
- Common
- Usually due to refractive error in one or both eyes.
- Can be treated with glasses but may require surgery.
- Squinting eye most often turns inwards (convergent) but there can be outwards (divergent), or rarely vertical deviation.
Non-concomitant (paralytic)
- Rare
- Usually due to paralysis of cranial nerves (III, IV, VI)
- Squint varies with gaze direction due to muscle paralysis
- Can be sinister as possibility of underlying brain tumour
What is a latent squint?
Squint controlled by subconscious effort and is not always apparent. In situations such as fatigue, the control is lost and the squint will manifest. Only appears when fixation interrupted (cover test)
Screening for squint?
Corneal light reflex test
- Pen torch held at distance to produce reflections on both corneas simultaneously. Light reflection should appear in same position on both pupils – if not, they are misaligned.
Cover test for squint?
Testing for RAPD?
Swinging Light Test (Marcus Gunn pupil)
- Keep on each pupil for around 2 secs
- Abnormal if pupil dilates with light shone on it
Indicated abnormality before the chiasm
Features of hypertensive retinopathy?
- I – Generalised arterial narrowing, altered light reflex, increased tortuosity
- II – AV nipping, regions of focal narrowing,
- III – Flame and splinter haemorrhages, cotton wool spots (due to retinal oedema), hard exudates
- IV – All the above, retinal & optic disc oedema (papilloedema)
Features of diabetic retinopathy?
- Background Diabetic Retinopathy
- Microaneurysms, dot and blot haemorrhages, hard exudates
- Maculopathy
- Accumulation of haemorrhages and hard exudate around the macula often accompanied by decreasing visual acuity. Also oedema close to fovea.
- Pre-proliferative Diabetic Retinopathy
- Exacerbation of background Diabetic retinopathy plus multiple cotton wool spots
- Intraretinal Microvascular Abnormalities (IRMA): irregularly-shaped blood vessels
- Proliferative Diabetic Retinopathy
- New vessel formation (near disc and ischaemic areas)
