Abstract
Purpose: :
While the correlation of signs and symptoms has traditionally been described as poor, tear film osmolarity has been heralded as a new diagnostic tool with improved sensitivity and specificity in the diagnosis of dry eye. We evaluated the tear film osmolarity and a battery of subjective and objective routine dry eye tests used to calculate a dry eye severity score (DESS) in patients with rheumatoid arthritis (RA) or Sjögren Syndrom (SS) compared to a control group of normal individuals in a prospective study.
Methods: :
95 consecutive patients (84 RA, 11 SS) were examined in a standardized fashion sequence in 2009. A control group of 50 patients without dry eye symptoms were examined for comparison. Following tests were performed: Tear Osmolarity (Tearlab®), Schirmer test, Ocular surface Disease Index (OSDI), corneal Fluorescein and conjunctival Lissamin green staining. In addition the morphology and function of the Meibomian glands was also graded. DESS was calculated using a normalized scale for all test parameters (0 to 1.0 = no dry eye to maximum severity of dry eye). The more severely affected eye from both eyes was analysed. Unpaired Wilcox test was used for comparison of RA/SS group to control group and linear regression analysis performed.
Results: :
Average Tear Film Osmolarity in the RA group was 308 (± 14,9) mOsmol/l, in the SS group 321 (± 18,5) mOsmol/l and in the control group 309,88 (± 16,6) mOsmol/l. There was no significant difference between controls and the RR group (p=0,6) but between controls and the SS group (p=0,05). Maximum DESS was 0,21 (± 0,08) in RA, 0,35 (± 0,12) in SA group and 0,21 (±0,08) in the control group. There was no significant difference between controls and RR group (p=0,9) but between controls and SS group (p=0,004). Linear regression analysis showed best correlation of DESS in RA+SS group with Corneal staining (R2=0,64) and Tear Film Osmolarity (R2=0,60). All other tests showed lower correlation.
Conclusions: :
Tear Film osmolarity and DESS is not generally elevated in RA patients but significantly elevated in SS patients. Among the evaluated tests, tear film osmolarity and corneal staining has the highest correlation with the severity of dry eye. While the DESS requires involvement of an ophthalmologist, the new tear film osmolarity measurement is easy to perform even for non ophthalmologists and therefore a good screening parameter for the evaluation of dry eye symptoms in patients with RA and SS.
Keywords: cornea: tears/tear film/dry eye • detection • autoimmune disease