Reduced corneal sensitivity in patients with rheumatoid arthritis

Up to one third of rheumatoid arthritis (RA) patients complain of dry eyes. The altered corneal sensitivity can be the consequence or the cause of the chronic reduction in tear secretion, or reduced tear production can cause the change of corneal sensitivity. The aim of this study was to assess the relationship among the symptoms, signs of dry eyes, and corneal sensitivity in RA and evaluate the association among the corneal sensitivity and clinical variables of RA.

A total of 106 RA patients and 40 control subjects participated in the study. Subjective symptoms of ocular dryness were explored using Ocular Surface Disease Index (OSDI), and objective signs including Schirmer test and tear break-up time (tBUT) were measured. Corneal sensitivity was determined by evaluating the corneal touch threshold using a Cochet-Bonnet esthesiometer. Clinical assessment of RA activity included C-reactive protein, Disease Activity Score 28, and Health Assessment Questionnaire.

Schirmer test scores and tBUT were significantly lower and OSDI was significantly higher in RA patients. The mean corneal sensitivities significantly reduced in the patient group but failed to show any correlations with Schirmer test, tBUT, and OSDI. Corneal sensitivity showed significant negative correlation with rheumatoid factor but failed to show any correlations with C-reactive protein, Health Assessment Questionnaire, and Disease Activity Score 28.

Corneal sensitivity was reduced in RA patients but failed to show any association with the subjective symptoms and objective signs of dry eyes. We could assume that reduced corneal sensitivity does not represent a sign of inflammation.