Episcleritis 

• Mild eye pain and redness, mildly uncomfortable and non-tender to pressure. It is benign and self-limiting.

Iritis

• Inflammation of the anterior portion of the uvea. The term anterior uveitis encompasses both iritis (inflammation of the iris) and iridocyclitis (inflammation of the iris and ciliary body). It mostly affects people between the ages of 20 and 50 and is uncommon in children. There may be an inflammatory cause: h/o back pain may indicate a possible seronegative spondyloarthropathy. Ulcerative colitis. Typical symptoms include a painful red eye, photophobia, blurred vision and associated headache. Iritis (and uveitis) tends to be unilateral, with redness and pain or photophobia. There is usually a poorly reacting pupil which may be irregular.

Case

• A 25-year-old male patient, with no significant past medical history, presents with a painful red right eye. He does not usually wear glasses, but on examination his visual acuity is 6/12 in the affected eye. The redness is concentrated around the cornea and his right pupil is smaller than his left.

• This patient has iritis. The symptoms/signs pointing to this diagnosis are: 'circumlimbial' pattern of injection, eye pain, reduction in visual acuity and pupillary change.

• Acute conjunctivitis usually presents with diffuse conjunctival injection and normal visual acuity; there should not be any pupil changes. In this age group acute glaucoma is unlikely especially in the absence of any ophthalmic history.

Uveitis

• Inflammation of the iris, ciliary body and/or choroid. It often presents with a sore, red eye and can cause visual loss.  It can present with floating spots in field of vision or blurred vision. It can occur at any age; but most commonly between ages of 20–50 years.

Scleritis

• Unlike the mild sensitivity of episcleritis, true scleritis presents with severe, boring ocular pain which may also involve the adjacent head and facial regions. The scleral vessels are significantly dilated, as are the overlying vessels of the episclera and bulbar conjunctiva. The affected eye may be so injected in some cases that the eye actually takes on a deep red, almost purple, hue.

• Often associated with connective tissue diseases. It requires urgent ophthalmology assessment as systemic treatment may be required. Without treatment, permanent loss of vision may occur in the affected eye or even perforation of the globe. Any rheumatoid patient with a very painful eye should be referred for further assessment.

• A drop of phenylephrine 2.5% causes visible blanching of the episcleral vessels in episcleritis, but will not do so in scleritis. Examination with a slit lamp microscope is also helpful in diagnosis.

Resources

• Uveitis (CKS) / Uveitis (Moorfields eye hospital)​, Episcleritis (Moorfields eye hospital)