Researchers have now put a number on the correlation between signs and symptoms of dry eye disease (DED), and it’s less than 0.15. For those rusty on their statistics, that figure (called rho or correlation coefficient) is calculated on a 0.0 to 1.0 scale, with 1.0 being perfect correlation. The 0.15 identified here falls well short.

Using data from the Dry Eye Assessment and Management (DREAM) Study, researchers looked at 1,022 eyes from 535 DED patients at 27 clinical centers across the United States based on Ocular Surface Disease Index (OSDI) questionnaires, conjunctival and corneal staining, Schirmer test and tear break-up time (TBUT). As expected, the correlation between these was small and not statistically significant, each one calculated at below 0.15.

“Often in clinical practice, we see patients with horrible symptoms of dry eye but no signs or very few signs, and vice-versa,” says Joseph P. Shovlin of Scranton, PA. “This study serves to reiterate the poor correlation between signs and symptoms in dry eye disease.”

While this paltry correlation has already been extensively reported, these results represent “a rigorous clinical trial setting with a large and diverse sample of DED patients,” the researchers said. “However, eligibility restrictions on the range of both signs and symptoms may have attenuated the associations relative to the entire patient population.”

These finding were presented earlier this week during the ARVO annual meeting.

Pistilli M, Maguire MG, Greiner JV, Asbell PA. The association between signs and symptoms in patients with dry eye disease. ARVO 2018. Abstract 924-B0102.