Red eyes

Conjunctivitis
     Infective and allergic
 
Dry eye syndrome
 
Episcleritis and scleritis
 
Corneal ulcers and keratitis
 
Iritis and uveitis

Characteristic or site

Conjunctivitis

Subconjunctival haemorrhage

Keratitis

Uveitis

Glaucoma

Scleritis

Hyperaemia

Diffuse

Diffuse

Diffuse

Diffuse

Diffuse

Focal or diffuse

Discharge

Yes

No

No

Minimal

No

No

Pupil

Unaffected

Unaffected

Constricted if secondary uveitis present, otherwise not affected

Constricted: poor light response

Moderately dilated; unreactive to light

Constricted if secondary uveitis present, otherwise not affected

Vision

Generally unaffected

Unaffected

Moderately to severely reduced

Mildly to moderately reduced

Severely reduced

May be reduced

Ocular pain

Essentially none

Essentially none

Moderate to severe

Moderate

Moderate to severe (often including headaches and vomiting)

Moderate to severe

Cornea

Clear

Clear

Hazy

May be hazy

Hazy

Occasional peripheral opacity

Prevalence

Very common

Common

Uncommon

Uncommon

Uncommon

Uncommon

Data from: [West, 2000Gray and Rosen, 2008]