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Three Part Question

In [patients with suspected iritis] does [the presence of a normal pupil] exclude [the diagnosis of iritis]

Clinical Scenario

A patient presents to the emergency department with a unilateral, red, painful eye. Visual acuity is reduced in the affected eye. The pupil is normal and the cornea is clear. There is some cillary flush around the iris. You can't decide if the diagnosis of iritis is correct or not. The other features of iritis (i.e unilateral, red, painful, decreased visual acurity) are present but the pupil remains a normal size and shape. Is this a common presentation?

Search Strategy

Ovid MEDLINE(R) 1966 to June Week 2 2006
Embase 1980 to 2006 Week 25
CINAHL 1982 to June Week 3 2006
{[Iritis.mp. or exp Iritis or Anterior uveitis.mp. or exp Uveitis, Anterior or exp Uveitis or exp iridocyclitis PR cyc;it is.mp] and [Pupil.mp. or exp Pupil or exp Adhesions or Adhesions.mp. or posterior synechiae.mp. or Iris.mp. or exp Iris or irregular pupil.mp.] and [exp Diagnosis/or Diagnosis.mp.]} LIMIT to [humans and english language]
Cochrane
Iritis AND (Pupil Size OR Irregular Pupil)

Search Outcome

Medline 313 papers were found in Medline of which only 1 was relevant to the question.
No further papers were gained from searching Embase, CINHAL or the Cochrane databases.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Oksala A 1977 Findland	25 patients with unilateral acute anterior uveitis The affected eye compared to the normal eye. Eyes examined with a slit lamp and then with ultrasound.	Cohort Study	Ability to visualise the vitreous body in acute anterior uveitis	7 of 25 eyes unable to see vitreous body because of the formation of posterior synechiae causing the pupil to be miosed in first presentation of acute uveitis 18 of 25 eyes did not present with a change in pupil size or shape	Small number of patients sampled

Comment(s)

From the review of the literature only one paper was found to look at the examination of the eye in acute anterior uveitis. Seven of the eyes presented with a change in pupil size compared with the other normal eye. In all cases the pupil was miosed (small). All the other 18 eyes presenting with anterior uveitis had normal pupils. The paper states that the formation of posterior synechiae (adhesions between the iris and the lens) are the cause of the miosed pupil. Posterior synechiae are a common feature of iritis. In another study on iridocyclitis in patients with juvenile rheumatoid arthritis, 61% of their patients enrolled had posterior synechiae[1]. Posterior synechiae is considered to be a complication of prolonged inflammation in the eye. Hence in the early stages of a first presentation of acute anterior uveitis, there may be no adhesions and therefore the pupil will be normal. There is no evidence to suggest iritis presents with an abnormal pupil in all cases. An irregular pupil may be seen only after posterior synechiae have formed owing to chronic inflammation, usually as the pupil is artificially dilated. In another study on iridocyclitis in patients with juvenile rheumatoid arthritis, 61% of their patients enroled had posterior synechiae (Key).

Clinical Bottom Line

Patients that present with an acute attack of iritis (anterior uveitis) often have no change in pupil size or shape, that is their pupil is normal compared to their other eye.

References

1. Oksala A. Ulrasonic Findings in the Vitreous body in patients with Acute Anterior Uveitis. Acta Ophthalmologica 1977 Vol 55 p287-293.
2. Key SN III, Kimura SJ. Iridocyclitis associated with juvenile rheumatoid arthritis. American Journal of Ophthalmology 1975;80:425-9.