Sir,

We congratulate the authors on the creation and evaluation of their Red Eye Algorithm, for use in primary care settings.1 This algorithm suggests that bilateral red eyes, with signs and symptoms of infective conjunctivitis, should be given 2 weeks of chloramphenicol drops before review by their GP. However, we would suggest that, because of its prevalence and wider health implications, primary care practitioners should be encouraged to consider the possibility of chlamydial conjunctivitis and initiate investigations when appropriate.

It is estimated that the proportion of patients presenting with acute infective conjunctivitis in secondary care, diagnosed with chlamydial conjunctivitis, is around 2.5–5.6%.2 However, it can be as high as 10% in 16–20 year olds3 and up to 34%4 among patients referred to some ophthalmology clinics.

We performed a retrospective audit of eye swabs, taken from last 300 patients referred to our Emergency Eye Care clinic, with apparent acute infective conjunctivitis. We found 15% tested positive on Chlamydial PCR. The proportion of positive swabs varied significantly according to age, with 29% of positive swabs taken from those aged 20–29 years, compared with 1% from those aged 40 years and over (see Table 1).

Table 1 Patient demographics for chlamydial positive swabs
Full size table

One would not wish to encourage mass screening of all conjunctivitis. However, the decision to swab for chlamydia is driven by specific features of the history including patient demographics, asymmetry and chronicity of symptoms, along with characteristic signs such as preauricular lymphadenopathy and follicles, which would be apparent in a primary care setting.5 Up to 54% of men and 74% of women would be expected to have concurrent genital infection when presenting with chlamydial conjunctivitis,2 although the majority of cases would be asymptomatic.5

We would therefore wish to encourage GP’s using the Edinburgh Red Eye Diagnostic Algorithm, seeing apparent infective conjunctivitis cases, to consider taking swabs for chlamydia based on patient demographics, history and clinical features. This will minimize delay in diagnosis, or avoid entirely missing the opportunity to pick up chlamydial conjunctivitis, and prevent the systemic and public health implications of an untreated asymptomatic genital infection.