Iritis: The Eye in General Practice PDF

Iritis is the commonest type of intraocular inflammation and one of the commonest causes of a unilateral red eye. GPs should consider the diagnosis in every patient who presents with a red eye. Included in this document History Examination Differential diagnosis When to refe...

Iritis is the commonest type of intraocular inflammation and one of the commonest causes of a unilateral red eye. GPs should consider the diagnosis in every patient who presents with a red eye. Included in this document History Examination Differential diagnosis When to refer Key points History Ocular Many patients with iritis have had the disease before and those with recurrent iritis are often aware of symptoms long before there are any signs. Therefore, any patient with a history of iritis and a red eye or symptoms consistent with iritis has a recurrence until proven otherwise. The principal symptoms of iritis are a watery red eye, pain and photophobia (light sensitivity). Symptoms usually come on over 24 to 48 hours. The pain is deep and dull. Patients keep their eyes closed and/or wear sunglasses. The vision is usually mildly decreased. Medical About 10% of patients with iritis have a systemic association. It is therefore very important to specifically ask about the symptoms of diseases such as ankylosing spondylitis, inflammatory bowel disease, tuberculosis and sarcoidosis. Examination Vision Photophobia can make testing the vision very difficult. It is often possible to get a much better result if the patient is tested in a darkened room. The vision is also often better when the pupil is dilated and pupil spasm is relieved. Eye The eye is usually very red. The redness is classically greater at the limbus and is known as ciliary or circumcorneal injection, because this is the area overlying the root of the inflamed iris and adjacent ciliary body (Fig. 1). The cornea is usually clear and the pupil is very small unless synechiae prohibit miosis. The iris details are occasionally hazy due to obscuration by inflammatory cells and proteins in the anterior chamber. Dilated examination Dilating the pupil helps with the diagnosis. Patients with posterior synechiae (adhesions between inflamed iris and the surface of the lens) either have or have had iritis, so look carefully for irregularities of the dilated pupil (Fig. 2). Occasionally it is possible to see keratic precipitates, condensations of inflammatory cells on the corneal endothelium, against the red reflex (Fig. 3). Fig. 1. Ciliary or circumcorneal Fig. 2. Synechiae. This patient has Fig. 3. Keratic precipitates. injection. Note how the vessels severe iritis. The pupil will not dilate overlying the iris root are very dilated fully due to the presence of posterior whereas those in the conjunctival synechiae - adhesions between the  fornix are normal. (Courtesy Dr D. posterior surface of the iris and the Peart.) anterior surface of the underlying lens. Differential diagnosis There are many conditions that mimic iritis but in most cases there are enough unique symptoms and signs to enable one to make the diagnosis. Foreign body In most cases foreign bodies cause instant discomfort that is made worse with each blink or eye movement. There is no circumcorneal injection, although there may be a localised area of redness adjacent to a peripheral corneal foreign body, or around one on the conjunctiva. Beware when patients tell you they have a foreign body in the eye. Often they have a foreign body sensation but no actual foreign body present. Fig. 4. Conjunctivitis. In contrast to the signs of iritis the circumcorneal vessels are normal. The conjunctival vessels are very engorged and appear like tiny springs. Conjunctivitis Conjunctivitis is usually bilateral although one eye may be affected before the other. There is often a history of upper respiratory tract infection and a preauricular lymph node is pathognomonic. In conjunctivitis, the vascular changes are more obvious in the conjunctival fornix, away from the iris root (Fig. 4). Herpes keratitis These patients also usually have an ocular history, in this case of a herpetic ulcer. The eye is more pink-red; the pupil is usually normal and most importantly an ulcer will stain with fluorescein. Acute angle closure glaucoma This is typically a disease that affects the elderly. The pain is deep and visceral. Angle closure glaucoma is the only ocular disease that causes nausea. The pupil is normally mid-dilated and non-reactive; the cornea uniformly cloudy and the vision poor. The eye is hard to palpation. Corneal ulcer The cardinal sign of a corneal ulcer is corneal opacification. Hypopyon is more common in corneal ulcers than iritis. When to refer All patients with iritis need to be seen by an ophthalmologist. Those with recurrent iritis can be started on treatment in consultation with their specialist but will still need review within 48 hours. Key points Consider the possibility of iritis in any patient with a unilateral red eye. Any patient with previous iritis, and either symptoms or signs of ocular inflammation, has a recurrence until proven otherwise. The cardinal signs of iritis are a watery eye, pericorneal injection, miosis, photophobia and mild visual loss. © GP Eyes - Dr Malcolm McKellar 2011