Ophthalmology SC008: The Red Eye Flashcards
Red eyes
Pathology occurring at ***Anterior segment of eye (structures in front of vitreous humour e.g. cornea, anterior sclera, conjunctiva —> exposed to external environment)
- > 60% eye pathologies can result in red eyes
- Majority due to dilated blood vessels on white sclera —> eye appears red
- Cardinal sign of inflammation
- Important associated symptoms: **Pain, **Visual loss
Causes:
1. Anterior segment diseases (e.g. conjunctivitis) (most common)
2. Posterior segment diseases (e.g. intraocular diseases)
3. Adnexa diseases (e.g. lids, muscles, orbit, lacrimal system)
Injection = Redness
Classification of red eye
- Distribution
- Anatomical site of pathology
Distribution:
1. Sectorial injection (localised area)
- **Subconjunctival haemorrhage
- **Episcleritis / Scleritis
- Circumferential / Ciliary injection (injection around limbal area, ciliary: ∵ this area supplied by anterior ciliary artery)
- Inflammatory conditions of anterior segment of eye
—> **Uveitis
—> **Acute angle closure glaucoma - Diffuse injection
- Infection (e.g. ***Conjunctivitis)
- More serious intraocular inflammation
Limbus: transition between cornea and sclera
Location + Extent of injection do ***NOT imply severity of condition
- e.g. allergic conjunctivitis / viral conjunctivitis can present with diffuse injection (but vision not affected, will go away in 1-2 weeks)
- e.g. scleritis associated with systemic diseases —> can be severe
Anatomical site of pathology:
1. Cornea
2. Conjunctiva
3. Sclera
4. Intraocular
5. Ocular adnexa (adjacent structures of eye)
Common eye complaints
- Redness
- Pain (signify more severe irritation / damage to eye)
- Blurring of vision (BOV) (signify more severe irritation / damage to eye)
—> Characterise complaint via History + PE
Case 1:
- 60/M
- OD redness for 2 days (Oculus dexter: Right eye, Oculus sinister: Left eye)
- No pain, No BOV, No trauma
- PMHx: DM, HT, Lipids, IHD on aspirin
PE:
- Bright red, homogenous, sectorial injection at right lower quadrant obscuring entire sclera
Dx:
- Subconjunctival haemorrhage
Subconjunctival haemorrhage (SCH)
Bleeding from ruptured small blood vessels between conjunctiva and sclera
Causes:
1. **Trauma (e.g. rubbing, use of contact lens, blunt / penetrating eye injury)
2. **Post-surgery
3. ***Valsalva (e.g. coughing, sneezing, constipation, vomiting, heavy lifting, straining)
4. Idiopathic
Symptoms:
- **Asymptomatic
- Sudden onset
- Red eye
- **Painless
- Normal vision
Signs:
- Bright red bleeding underneath conjunctiva, view of sclera can be entirely obscured
Risk factors:
- Systemic vascular diseases: **HT (very common), DM
- Medications: Antiplatelets / Anticoagulants
- **Coagulopathy / Bleeding disorders (rare)
Investigations:
- Check **BP (high yield)
- **Plt, PT, aPTT (if recurrence / other bleeding tendency)
Management:
- No further workup needed (Spot diagnosis)
- None required
- ***Benign, self-limiting —> resolve after 2-3 weeks
- Referral to family doctors / physicians as indicated for HT / Bleeding disorders
Case 2:
- 10/M
- OU redness for 1 week (OU: Oculus uterque —> Both eyes)
- Itch, discharge, crusting in morning
- URTI +
- PMHx: allergic rhinitis, eczema
Discharge: Mucoid / Purulent —> Crusting in morning
PE:
- Diffuse mild injection
- Undersurface of eyelid: large, nodules, cobblestone appearance —> ***Papillae
Papillae:
- stromal tissue swelling around central core of vessel
- size from small to giant cobblestone appearance
- common in ***allergic conjunctivitis
- can cause discomfort, corneal abrasion
Follicles:
- small dome-shaped lymphoid aggregates in conjunctiva
- usually in ***viral conjunctivitis
Dx:
- Mixture of allergic / viral conjunctivitis
***Conjunctivitis
Hard to distinguish between different causes
Causes:
1. Allergic (most common, associated with atopy in children / young adults)
- **Itchiness: +++
- Discharge: **Watery, white mucus
- Features: **Papillae (pathognomonic), Pink eyes
- Systemic: **Atopy (allergic rhinitis, eczema), Contact allergens
- Common pathogens: Nil
- Treatment:
—> Avoid allergens
—> Supportive: Cool compresses, Artificial tears
—> **Antihistamines (topical / oral), **Mast cell stabilisers, Dual-activity agents
—> Topical steroids
- Viral (most common, usually peak in summer ∵ swimming)
- Itchiness: +
- Discharge: **Serous, **Crusting / gluing of eyelids upon waking
- Features: Red eye (conjunctival hyperaemia), **Conjunctival follicles (pathognomonic), **Foreign body sensation / irritation (rather than frank pain)
- Systemic: **URTI
- Common pathogens: **Adenovirus (associated with recent URTI, adenovirus in URT —> spread via direct contact, **highly contagious, can spread to **contralateral eye within a few days, household members affected)
- Treatment: Self-limiting (2-3 weeks), Contact precaution (no rubbing, no sharing of towels, frequent hand washing, restrict work / school ~1 weeks ∵ most contagious period first 7-12 days) - Bacterial (rare)
- mild form: clinically indistinguishable from viral causes
- severe form: **Mucopurulent discharge, **acute onset, **rapid progression
- Itchiness: +/- (less prominent)
- **Discharge: Mucopurulent
- Features: Nil
- Systemic: Nil
- Common pathogens: Staphylococcus (eyelid flora), Streptococcus (URT coloniser), Haemophilus (URT coloniser)
- Treatment: Self-limiting (if mild), Topical antibiotics
Case 3:
- OS redness since evening
- Pain ++ radiating to periocular region, Vomiting x1
- BOV +
- PMHx: Hyperope +4D, recent URTI, taking OTC medication
PE:
- Heterogeneous (compared to SCH)
- Diffuse injection
- Semi-dilated pupil
Dx:
- Acute primary angle closure (APAC) / Acute angle closure glaucoma (AACG)
Acute primary angle closure (APAC)
Previously known as Acute angle closure glaucoma (AACG)
Symptoms:
1. **Severe ocular pain, **acute onset (∵ sudden buildup of IOP: >45), may radiate other areas (e.g. periocular area, forehead)
2. Frontal headache
3. **BOV (cornea become hazy if prolonged ↑ IOP)
4. **Halos around lights
5. N+V
Signs:
1. **Fixed mid-dilated pupil (∵ high IOP —> ciliary muscle becomes ischemic —> can no longer constrict the pupil)
2. **Corneal haze / edema
3. **Shallow anterior chamber (on slit lamp exam)
4. Conjunctival injection (Ciliary flush)
5. **Very high intraocular pressure (>45 mmHg)
Risk factors:
- **Female
- Asian
- Old age
- **Hyperopia (short axial length)
- ***Shallow anterior chamber
- Family history
Precipitating factors:
- Topical **mydriatics
- Systemic **anticholinergics (e.g. antihistamine, bronchodilator, antipsychotic) —> dilate pupil
- Dim illumination
- Accommodation (e.g. reading) —> thicker lens
Aims of treatment:
1. Abort pupil block (due to dilated pupil)
2. ↓ IOP
3. Create alternative pathway for drainage (definitive treatment)
Immediate treatment:
1. ***Pilocarpine 4% (miotic agent, every 15 mins for 1 hour —> abort pupil block)
- ***IOP lowering agents
- Timolol 5% (↓ aqueous production)
- Apraclonidine 0.5% (α agonist) - Systemic
- ***IV Acetazolamide 500mg (one injection, ↓ IOP quickly, caution in renal impairment)
- IV Mannitol 20% 200ml (hyperosmotic agent —> draw fluid from eye into blood, caution in HT ∵ ↑ intravascular volume)
Definitive treatment (Surgery):
1. ***Peripheral iridotomy (create alternative pathway to anterior chamber)
2. Lens extraction
3. Prophylactic iridotomy in contralateral eye
Mechanism of APAC: Aqueous outflow and pupil block
Aqueous: produced by ciliary body
- balanced production / outflow to maintain IOP
Mechanism of APAC:
Pupillary block from apposition of lens and posterior iris
—> Blockage of aqueous humour flow
—> ↑ posterior chamber pressure
—> Forward movement of peripheral iris (iris pushed anteriorly)
—> Trabecular meshwork obstruction (i.e. Close angle (even more obstruction to outflow))
Pupil block
Predisposing factors:
- **Thick lens —> touching iris —> block outflow pathway
- **Short axial length / **Shallow anterior chamber —> iris appose lens —> block outflow pathway
- **Pupil dilation —> iris can appose lens —> block outflow pathway
Terminology of angle-closure glaucoma
- Primary angle closure suspect (PACS)
- Primary angle closure (PAC)
- ***Acute Primary Angle Closure (APAC) (just describe pathology, does not imply permanent optic nerve damage) (replaced AACG) - Primary angle closure glaucoma (PACG)
- glaucoma: imply documented optic nerve damage
1 —> 2 —> 3
Carbonic anhydrase inhibitor
Altitude sickness
Prevent carbonic acid breakdown
—> Accumulation of carbonic acid
—> Lower blood pH
—> Hyperventilation
Carbonic anhydrase:
- in RBC, Proximal tubule —> reabsorb Na, Cl, HCO3, Ciliary body —> Aqueous production
- when inhibited
—> Na, Cl, HCO3 excreted
—> diuresis
—> excretion of excess water
—> ↓ BP, ICP, IOP
Case 4:
- 20/F
- OS redness for 1 day
- Pain ++
- BOV +
- Overnight contact lens use
- Good past health
PE:
- Ulcer on corneal epithelium
- Infiltrate in lower iris (i.e. indicate infection)
Contact lens use:
- must rule out ***infectious keratitis (corneal infection) if presenting with painful red eye
Infectious keratitis
Organism:
1. Bacterial
- Staphylococcus, Streptococcus (lid flora)
- ***Pseudomonas (must rule out, contact lens related ∵ rapidly progressive + cause abscess)
- Moraxella
- ***Protozoa: Acanthamoeba (must rule out, contact lens related, signs not obvious, symptoms not proportionate to signs e.g. severe ocular pain)
- Fungus (history of minor trauma in particular with vegetable matters e.g. tree branches, soils)
- Virus: ***HSV (Dendritic ulcers) / VZV
Clinical features:
- Painful red eye
- Severe injection
- Photophobia
- Decreased vision
- Infiltrate (focal white opacity) in corneal **stroma, abscess formation (severe cases)
- **Corneal ulcer with epithelial loss
- Eyelid edema
Investigations:
- ***Corneal scraping —> culture + sensitivity
Management:
1. ***Broad spectrum topical antibiotics (good Gram +ve + -ve coverage)
- Levofloxacin
- Moxifloxacin
- Fortified Vancomycin + Gentamicin / Ceftazidime (for MRSA)
—> Titrate according to C/S results
- ***Topical aciclovir for Viral keratitis
Contact lens use:
- must follow schedule (e.g. one day use)
- good disinfection habit for long term contact lens
- no overnight sleep
- no swimming with contact lens
Case 5:
- OS redness for 3 days
- Dull aching pain +
- No BOV
- PMHx: unremarkable
PE:
- Temporal injection with 2 layers (superficial + deep)
Dx:
- Scleritis
