Acute Red Eye : Simplified Approach

Red eye reflects hyperemia or engorgement of superficial visible conjunctival, episcleral or ciliary vessels.


1. Painless red eye:

acute red eyea) Diffuse redness:

  • Lids normal: Conjunctivitis
  • Lids abnormal:
    • Blepharitis
    • Ectropion
    • Trichiasis
    • Eyelid lesion

b) Localized redness:

  • Pterygium
  • Corneal foreign body
  • Ocular trauma
  • Subconjunctival hemorrhage
  • Episcleritis

2. Painful red eye:

a. Cornea abnormal:

  • Herpes simplex keratitis
  • Bacterial/Acanthamoebal ulcer
  • Marginal keratitis
  • Foreign body/Corneal abrasion

b. Lids abnormal:

  • Chalazion
  • Blepharitis
  • Herpes zoster

c. Diffuse Conjunctival congestion:

  • Viral conjunctivitis
  • Allergic conjunctivitis
  • Bacterial conjunctivitis
  • Dry eyes

d. Ciliary congestion:

  • Angle closure glaucoma
  • Anterior uveitis (Iridocyclitis)

e. Scleral congestion:

  • Scleritis


Perform systematic ocular history and examination with special emphasis on:

Step 1:  Assess for possible causes of red eye

  • Trauma (foreign body, subconjunctival hemorrhage)
  • Recent ocular history such as surgery (postoperative endophthalmitis)
  • Previous history of Angle closure glaucoma, uveitis or systemic illness

Step 2: Painful or painless red eye ?

Step 3: If the pain is deep – assess for pattern of redness

a. Diffuse: Examine eyelids

  • Lids normal: Rule out scleritis
  • Lids abnormal:
    • With ptosis: Orbital cellulitis, Grave’s disease
    • Without ptosis: Grave’s disease

b. Focal: Scleritis

c. Ciliary: Examine pupils

  • Mid-dilated: Acute angle closure glaucoma
  • Small or normal pupils: Evaluate anterior chamber
    • Cloudy: Evlauate cornea
      • Cornea clear: Anterior uveitis
      • White infiltrate: Corneal ulcer
    • Layered WBCs: Hypopyon
    • Layered RBCs: Hyphema

Step 4: If the pain is superficial – Assess vision

a. If decreased vision – Perform topical fluorescein staining

  • Foreign body
  • Chemical injury
  • Corneal abrasion
  • Corneal ulcer

b. If normal vision – Evaluate pattern of redness

  • Diffuse congestion: Examine lids
    • Abnormal: Blepharitis, Chalazion, Hordeolum
    • Normal: Note the type of discharge
      • No discharge: Non-specific conjunctivitis
      • Purulent: Bacterial conjunctivitis
      • Watery: Is itching present?
        • No itching: Viral conjunctivitis
        • Itching: Allergic conjunctivitis (Medication related or unrelated)
  • Focal: Is conjunctival lesion present:
    • Conjunctival lesion present: Pingueculum, Pterygium
    • Conjunctival lesion not present: Subconjunctival hemorrhage, Episcleritis

Step 5: If there’s no pain but the vision is poor – possible causes are

  • Vasculitis
  • Vitreitis
  • Retinitis
Cause of red eye
conjun-ctival hemor-rhage
KeratitisIritisAcute angle closure glaucomaScleritis
Conjes-tionDiffuse, unilateral or bilateralUnilateral, not truly injected but rather discrete confluent changeCiliary pattern,unilateralCiliary pattern, unilateralCiliary pattern, unilateralLocalised, unilateral
CorneaClearClearHazy, localised opacity (infiltrate), epithelial defect (fluorescein positive)May be hazyHazy, iris detail indistinctClear
PupilUnaffectedUnaffectedUnaffected (unless secondary uveitis present)Constricted, poor light response, may be distortedFixed, mid-dilatedUnaffected (unless secondary uveitis present)
VisionGenerally unaffectedUnaffectedModerately to severely reducedMildly to moderately reduced.Severely reduced, blurred, possible coloured halos around lightsMay be reduced
Disch-argeYes; purulent more likely with bacterial, watery more likely with viralMinimal (watery)Yes; usually wateryMinimal (watery)Minimal (watery)Minimal (watery)
PainYes; gritty or stabbing painGenerally noneYes; usually severeYes; moderate to severeYes; usually severe (with vomiting and headache), globe tender and hard if palpatedModerate to severe (described as deep pain), localised significant tenderness

Diagnostic aids for acute red eye:

  1. Light sensitivity: Iritis, keratitis, abrasion, ulcer
  2. Unilateral: Above + herpes simplex, acute angle closure glaucoma
  3. Significant pain: Above + scleritis
  4. White spot on cornea: Corneal ulcer
  5. Blurred vision: All of the above
  6. Non-reactive pupil: Acute glaucoma, iritis
  7. Copious discharge: Gonococcal conjunctivitis
  8. Blurred vision: All of the above


1. Orbital cellulitis:

  • lid erythema, proptosis,¬†and restricted eye movements,¬†pseudoptosis secondary to the swelling, fever, anorexia, malaise, eyelid and periocular pain, with¬†swelling, double/blurred vision
  • may give a history of sinusitis or preseptal celluitis
  • treatment:
    • Hospital admission
    • Send for CBC and blood cultures
    • Urgent CT: to rule out associated abscess
    • IV antibiotics: likely organisms are Strep. pyogenes, Strep. pneumoniae, Staph. aureus
      i.v. Ceftriaxone 50 mg/kg/dose (2g) iv 12H
      i.v. flucloxacillin 50 mg/kg/dose 6-hourly (maximum 2 g/dose).
    • If abscess is present:¬†Surgical drainage of an abscess

2. Scleritis:

  • Eye pain: severe, deep, boring in nature; disturbs¬†sleep; radiate to the eyebrow, forehead or jaw; exacerbated by¬†eye movements. Minimal and temporary relief of pain from analgesics.
  • Epiphora, Photophobia, Tender globe, Nausea/vomiting, Redness of the¬†eye, may complain of reduced vision
  • Examination in daylight ‚Äď the sclera may appear red/blue. There will¬†be injection of deep episcleral vessels that do not blanch on¬†phenylephrinene (10% drop) instillation. There may be areas of¬†scleral translucency (blue tinged) indicating thinning due to previous¬†episodes of scleritis. A severe necrotizing form of scleritis would be¬†indicated by black or brown areas. An area of central whiteness¬†indicates that this area has become avascular.
  • Slit lamp examination ‚Äď corneal/intraocular inflammation. Thickened¬†oedematous sclera.
  • 50% of cases are associated with an underlying¬†systemic condition – autoimmune diseases, arthritis, vasculitis and infections like TB, syphilis, varicella zoster (Look for underlying systemic disease)
  • More common in women with peak incidence in¬†50s.
  • Treatment

3. Acute Angle Closure Glaucoma:

  • History: Severe eye pain, nausea, vomiting, (may misleadingly present¬†as an acute abdomen), headache, red eye, rainbow halos around lights,¬†decreased vision. There may be a preceding history of intermittent¬†blurred vision, and halos around lights, for example after an evening in¬†a dark environment, due to transient closure of the irido-corneal angle¬†caused by pupil dilation.
  • Eamination: Poor visual acuity, red eye (ciliary flush), cloudy cornea¬†(secondary to corneal oedema), fixed and mid-dilated oval shaped¬†pupil, eye that is stone hard on palpation, shallow anterior chamber,¬†RAPD ‚Äď if optic nerve damage has occurred
  • Treatment:
    treatment acg


4. Anterior uveitis (Acute iridocyclitis):

  • History: Photophobia (due to reactive spasm of inflamed iris¬†muscle), ocular pain, tenderness of the globe, brow¬†ache (ciliary muscle spasm), decreased VA (in¬†severe cases with hypopyon), lacrimation
  • Examination:
    • Ciliary flush (perilimbal conjunctival injection),¬†miosis (spasm of sphincter muscle)
    • Anterior chamber ‚Äúcells‚ÄĚ (WBC in anterior chamber¬†due to anterior segment inflammation) and ‚Äúflare‚Ä̬†(protein precipitates in anterior chamber 2¬į to¬†inflammation)
    • Hypopyon (collection of neutrophilic¬†exudates inferiorly in the anterior chamber)
    • Occasionally keratic precipitates (clumps of cells on¬†corneal endothelium)
    • Typically reduces IOP because ciliary¬†body inflammation causes decreased aqueous¬†production; however, severe iritis, or iritis¬†from herpes simplex and zoster may cause an¬†inflammatory glaucoma (trabeculitis)
  • Look for arthritis, back pain, signs of tuberculosis and coexisting¬†medical conditions such as ulcerative colitis
  • Treatment: Severity of anterior uveitis can be graded based on severity of symptoms, decrease in visual acuity, depth of circumcorneal flush, density of KPs, flare reaction and rise in IOP
    • Mydriatics/Cycloplegics: Cyclopentolate, 1% (t.i.d.) or homatropine, 5% (b.i.d.-t.i.d.) or atropine 1% (bid-tid)
      • Relieves pain by immobilizing iris
      • Prevents synechiae formation
      • Stabilize blood-aqueous barrier and decrease flare reaction
    • Steroids (Anti-inflammatory): Prednisolone, 1% (b.i.d.-q.i.d.) or¬†Fluoromethalone 0.1% and 0.25%
    • NSAIDs: Oral aspirin or ibuprofen or flurbiprofen, 2 tablets (q.4h)
    • Consider beta blockers if IOP is elevated
    • Use dark glasses
    • Re-evaluate after 5-7 days (or sooner if severe) or p.r.n

6. Ocular foreign body:

If the patient was working with metal or wood, inspect the eye for a foreign body.

  • History: Sudden discomfort in eye,¬†Reflex blinking due to foreign body sensation,¬†irritation and gritty feeling if the foreign body , lacrimation and photophobia are present in cases of corneal involvement.
  • Examination:¬†reflex blepharospasm, foreign body is visible on the bulbar conjunctiva, limbus, cornea,¬†sulcus subtarsalis and fornix by the naked eye, oblique¬†illumination with a loupe or slit-lamp examination.
  • Treatment:
    • Step 1: Instil local anesthetic eyedrops
    • Step 2: Irrigation of eye
      • Position: sitting or lying down with neck and shoulders covered with waterproof sheet; head tilted towards affected side with kidney dish against cheek
      • Fill irrigating fluid: Fill the feeding cup with the irrigating fluid and test it for temperature by pouring a small amount against the patient’s cheek
      • Fix the gaze: Ask the patient to fix his/her gaze ahead
      • Retract eyelids: Spread open the eyelids, if necessary using eyelid retractors
      • Irrigate: Pour the fluid slowly and steadily, from a distance of no more than 5 centimetres, onto the front surface of the eye, and importantly, inside the lower eyelid and under the upper eyelid
      • Evert the upper eyelid to access all of the upper conjunctival fornix
      • Ask the patient to move the eye continuously in all directions while the irrigation is maintained for at least 15 minutes (30 minutes is better)
      • Remove any residual foreign bodies with moist cotton buds or forceps
      • Check and record the visual acuity when the procedure is finished
    • Step 3: For embedded corneal foreign body
      corneal foreign body removal

      • Instill fluorescein dye
      • Ask the patient to look straight ahead, fix gaze and keep perfectly still
      • With one hand, gently control the patient’s eyelids
      • With the other hand, support the sterile needle with two fingers and the thumb
      • Approach the cornea slowly with the bevel of the needle uppermost and horizontally ‚Äėflat on‚Äô to the cornea (tangential approach to prevent corneal perforation)
      • Gently lift off the foreign body (FB) from the corneal surface using lever movement.
      • Check the patient’s eye, carefully everting the upper eyelid to ensure no FB’s remain ‚Äď a corneal abrasion may be seen
      • If metal is lodged in the cornea for more than four to six hours, rust will begin to form in the adjacent tissue. This is typically seen as a brownish-orange ring that appears to feather into the surrounding tissue. Although the rust ring can occasionally be lifted in its entirety with a jeweler‚Äôs forceps, an Alger brush will be required in the vast majority of cases to free the area of rust.
      • Instill antibiotic ointment and apply a firm eye dressing, using two pads and a bandage, for 24 hours
    • Step 4: Follow up next day
      • Look for infection, iritis and recurrent corneal erosion.

7. Chemical injury of eye:

eye irrigationTreatment:

  • Immediately irrigate at site of accident with water or buffered solution¬†IV drip for at least 20-30 min with eyelids retracted in emergency department
  • Swab upper and lower fornices to remove possible particulate matter
  • Do not attempt to neutralize because the heat produced by the reaction will damage the cornea
  • Cycloplegic drops to decrease iris spasm (pain) and prevent 2¬į glaucoma (due to posterior¬†synechiae formation)
  • Topical antibiotics and patching
  • Topical steroids to decrease inflammation, use for less than 2 wk (in the¬†case of a persistent epithelial defect)

8. Eyelid lesions:


  • Crusting: Blepharitis
  • Towards eyelid margin; pus point: External hordeolum/stye
  • Away from eyelid margin; lumpy mass: Chalazion


  • Warm compresses (for 5 minutes) applied to the lids:
    • can increase oil production and melt the oil in the meibomian glands
    • use of a warm washcloth to apply heat
  • Eyelid scrub hygiene:
    • to remove eyelash debris, bacteria, bacteria toxins, oil and scurf
    • use a cotton earbud soaked in baby shampoo or modern methods like foam, gel and pre-moistened pads such as Ocusoft Eyelid Cleanser
  • Mechanical glandular eyelid massage:
    • to facilitate the flow of the meibomian oil from the glands
    • applying light pressure with a fingertip or a Q-Tip to the lid margin near the base of the lashes
  • Artificial Lubricants:
    • such as Ocusoft, re-lube, etc.
  • Topical (drops and ointments) antibiotics
  • Non-resolving:
    • Chalazion: Intralesional steroid or Incision and currettage
    • Stye (if abscess formed): Drain by pulling out eyelash or Incision
    • Blepharitis:
      • Topical corticosteroids (for < 2 weeks)
      • Others: Diet rich in Omega-3 fatty acids (fish, flax seed and walnuts)

11. Conjunctivitis:

a. Viral conjunctivitis:

  • Simple follicular conjunctivitis ‚Äď supportive; cold compresses over the¬†eyelids or artificial tears may provide some symptomatic relief. Strict¬†hygiene must be emphasized, e.g. hand washing, avoiding close¬†contact, not sharing towels.
  • Molluscum contagiosum: nodules can be excised.
  • Herpes simplex infection: topical aciclovir
  • Followup

b. Allergic conjunctivitis:

  • Eliminate underlying cause (allergen)
  • Topical antihistamine¬†and/or mast cell stabilizing drops
  • Follow-up is indicated only if symptomatic¬†treatment is ineffective.

c.  Bacterial conjunctivitis:

  • Gonococcus causes hyperacute puruplent conjunctivitis and is potentially sight threatening and requires urgent workup and treatment.
  • Less virulent: Streptococcus¬†pneumoniae, Haemophilus influenzae, and Chlamydia
  • Intitially empiric therapy: Broad-spectrum antibiotics like Ofloxacin (Exocin eye drops), Ciprofloxacin (Cipro-cent) eye ointment
  • Later specific therapy based on culture sensitivity

12. Pterygium and Pignguecula:

  • Pinguecula is an elastotic degeneration of conjunctiva that never encroanches cornea while Pterygium is a fibrovascular conjunctival growth that encroaches towards the cornea
  • Hence, pterygium may cause astigmatism and diplopia
  • Usually managed conservatively with artificial lubricants and uv protective glasses
  • Antibitoics and steroids can be used if inflamed
  • Pterygium excision¬†may be indicated in some cases


  • Severe eye pain
  • Severe photophobia
  • Marked redness of one eye (Unilateral)
  • Reduced visual acuity (after correcting for refractive errors)
  • Suspected penetrating eye injury
  • Worsening redness and pain occurring within one to two weeks of an intraocular procedure (Suspected endophthalmitis)
  • Irritant conjunctivitis caused by an acid or alkali burn or other highly irritating substance
  • Purulent conjunctivitis in a newborn infant

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