Abstract
Purpose :
Dry eye clinical trials often use endpoints based on tear film function, such as Schirmer's test and vital dyes, to measure ocular surface damage. Lissamine green (LG) is a vital dye that is underutilized in current clinical trials. In this secondary analysis, we calculated relative score variation between lissamine green and a standard test for tear volume (Schirmer's test) and compared variability over two visits for each outcome.
Methods :
Screening and pre-randomization data from two identically designed clinical trials (Phase 2 and Phase 3) were combined into one dataset. A total of 1049 subjects were screened, 494 met the inclusion criteria for pre-challenged and pre-drug data. In this secondary data analysis, only data from the pre-CAE timepoints at visit 1 and visit 2 were used. Schirmer’s scores were examined between visits 1 and 2 pre-CAE to determine the percent change in Schirmer’s test values from visit to visit. LG was assessed similarly in each of the following regions: central, inferior, nasal, superior, and temporal. Consistent values from visit to visit were defined as those with a percent change of 25% or less.
Results :
494 subjects met the screening criteria. When baseline Schirmer’s values were less than 8mm, the nasal LG scores were found to be significantly higher than nasal LG scores for patients who had Schirmer’s baseline values greater than 8 mm. This significant difference [p=0.039], however, was found only in the nasal region. A total of 66% of the study population had consistent LG results between visits 1 and 2, compared to only 33% for Schirmer's test.
Conclusions :
The LG exhibits greater consistency than the Schirmer’s test across multiple visits, suggesting that it can serve as a reliable primary indicator for assessing dry eye disease. While 10 mm on Schirmer’s testing has been historically accepted as the standard for normality of tear volume, this data suggests that lowering the metric to 8mm is more suitable. Lissamine staining in the nasal region appears to be the appropriate clinical metric for defining dry eye related ocular surface perturbation.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.