The repeatability of tests for dry eye signs and symptoms in the dry eye assessment and management (DREAM) study

Purpose

To assess the repeatability of measures for dry eye disease (DED) symptoms and signs in the DREAM study.

Methods

At screening and baseline visits approximately 2 weeks apart, participants were assessed for symptoms by Ocular Surface Disease Index (OSDI) and Brief Ocular Discomfort Index (BODI), and signs by the same physician in the same order: tear break-up time (TBUT), corneal staining, conjunctival staining, Meibomian gland evaluation, and the Schirmer test. The repeatability of DED symptoms and signs was assessed by interclass correlation coefficient (ICC), 95 % limits of agreement, and the percent of eyes with inter-visit difference above the clinically significant threshold.

Results

Among 1046 eyes (523 participants), ICC for signs ranged from 0.53 (TBUT) to 0.73 (corneal staining). A substantial percentage of eyes showed clinically significant inter-visit differences: ≥2 points in 17.8 % of eyes for conjunctival staining; ≥3 points in 18.8 % for corneal staining; >2 s in 14.1 % for TBUT; ≥5 mm/5 min in 29.9 % for the Schirmer test, and ≥ 2 points in 27.5 % for Meibomian gland plugging and lid secretion. The OSDI and BODI had ICC of 0.64 and 0.63 respectively, and nearly 40 % of participants had inter-visit score differences ≥ 10 points.

Conclusion

In DREAM participants with moderate-to-severe DED, DED signs and symptoms had moderate repeatability, with ocular surface staining scores being the most repeatable and TBUT the least repeatable. A notable percentage of participants had inter-visit differences above the clinically meaningful threshold. These test–retest variabilities in DED signs and symptoms should be considered for designing clinical trials and monitoring disease progression.