Temporal stability in the perception of dry eye ocular discomfort symptoms

A prospective longitudinal study was designed to investigate the ability of patients with tear deficiency to correctly recall their past symptoms. The ultimate goal of the study was to contribute to the ongoing research concerning the lack of association between dry eye symptomatology and clinical tests of tear film evaluation.

A total of 26 subjects with ages ranging from 29 to 61 years participated in the study. All subjects reported symptoms associated with tear deficiency, although none had been diagnosed with dry eye disease. Subjects were instructed to grade their symptoms on two different occasions, at the precise moment they were experiencing them, by means of a home questionnaire, and through a recall questionnaire, which was administered within a maximum interval of 10 days from the first questionnaire. Tear evaluation tests were performed at this second time. Non-parametric statistical analyses were used to investigate the relationship between present and recalled symptoms and between symptoms and signs, as well as between the different dry eye tests. The contributions of age, gender, and recall period were also evaluated.

With the exception of irritation (p = 0.029) and scratchiness (p = 0.025), no statistically significant difference was encountered between home and recall questionnaires, although females were found to recall their symptoms slightly better than males (p = 0.048). An increase in the severity of the symptoms was associated with a better recollection (p = 0.007). Symptoms (home or recalled) and clinical signs were not correlated, although the recalled symptom of scratchiness presented moderately strong correlations with several dry eye tests.

Although the lack of correlation between dry eye tests and symptoms mirrored previous research, symptoms recall was found to follow certain interesting patterns, similar to those published in pain research literature.