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We thank Dr Kotaniemi and associates for their comprehensive review1 of this important topic. Among all the ophthalmic measures studied, screening for dry eye by Schirmer’s test and interview alone aroused our interest.
Unlike other well known causes for Sjögren’s syndrome, such as systemic lupus erythematosus or rheumatoid arthritis, juvenile idiopathic arthritis is not commonly associated with dry eye or keratoconjunctivitis sicca. Carvounis et al have shown the prevalence to be as low as 2.3%.2 Surprisingly, Kotaniemi et al reported that a discordantly high 40% of patients with uveitis and 26% of non-uveitis patients had dry eye symptoms or signs.1 This obvious disparity may be attributed to multiple uncontrolled confounding factors in this study, including the intrinsically low reproducibility of the Schirmer score and poor correlation between conventional dry eye tests and symptoms.3,4
The coarse, primitive, and inaccurate nature of Schirmer’s test has led to a search for more objective alternatives—namely, meniscometry, interferometry, fluorophotometry, video-meibography, meibometry, and xerosis meter.5,6 The current trend in ophthalmic research into dry eye relies on an array of investigatory tests rather than a single test in order to increase the sensitivity, specificity, and degree of correlation.4,5
In this study, adoption of Schirmer’s test as the sole objective assessment for dry eye appeared unusual. We would be interested to learn from authors the rationale behind this choice.
We warmly thank Dr Chan and Dr Liu for their interest in our paper and their useful comments on our study.1
Dry eye syndrome is common in adult rheumatoid arthritis and it may often be underdiagnosed. In our clinic we carry out each year about 1300 ophthalmological examinations of children under 16 years of age with a diagnosis or suspected diagnosis of juvenile idiopathic arthritis (JIA). It is our impression also that dry eye syndrome is rare in this patient group.
In this study we had a good epidemiological base from which to evaluate young adults with JIA. When looking for the signs and symptoms of uveitis we had an opportunity to make a clinical evaluation of dry eye syndrome in our patient cohort. We asked the patients with JIA about their dry eye symptoms and carried out Schirmer’s test to measure the basal tear secretion after instillation of aesthetic drops in the eyes. If the tear flow was <10 mm in at least one of the patient’s eyes and she/he had dry eye symptoms, we regarded her/him as a patient with dry eye. The frequency of positive results was surprisingly high compared with the previous low figures.
There are different criteria for the diagnosis of Sjögren’s syndrome, and Schirmer’s test can be performed in several ways.2 At our hospital Schirmer’s test with topical anaesthesia seems to be good in clinical work in screening rheumatoid patients for dry eyes. For the patients with JIA of our study, we re-analysed the frequency of dry eyes with more specific criteria (Schirmer’s test result ⩽5 mm at least in one eye together with positive dry eye symptoms): the respective figures were 32% positive among patients with uveitis and 25% among those without uveitis. The figures are still relatively high. However, Packham and Hall found sicca syndrome in 15% of 246 adults with JIA and in 29.7% of those who had positive antinuclear antibody.3
The main topic of our study was JIA associated uveitis in young adults. Thus, we did not make any special efforts to evaluate the prevalence of secondary Sjögren’s syndrome in our patients. We used only clinical examination, questions about dry eye symptoms, and Schirmer’s test. The rose bengal dye test is seldom used, because it causes such irritation.
Several reasons are possible for the high prevalence of dry eye syndrome in young adults with JIA in our series in Finland—for example, the long duration of JIA (mean 16 years) and genetic and environmental (for example, cold climate) differences. However, further studies, with a larger number of patients are needed to clarify the prevalence and problem of dry eye syndrome in adult patients with JIA.