Researchers Put 2-Question Dry Eye Questionnaire to the Test

Young African male doctor uses with ophthalmoscope to examine patients eye
The Change in Dry Eye Symptoms Questionnaire (CDES) consists of only 2 questions and patient responses were aligned with clinical results.

A newly-proposed questionnaire related to the describing and quantifying of changes in the symptoms of dry eye disease (DED) may be more useful and appropriate than the previous options, according to findings published in Eye & Contact Lens.

Researchers at the University of Valladolid, Spain conducted a retrospective observational study to evaluate the 2-question Change in Dry Eye Symptoms Questionnaire (CDES-Q). The first question (CDES-Q1) asks patients to rate changes in symptoms using the options “better,” “same,” or “worse,” and the second question (CDES-Q2) requires a numerical rating of the change from 0 to +100. 

For the study, 36 patients made 2 visits to the laboratory. The first visit (V1) measured baseline values using the ocular surface disease index (OSDI) questionnaire, and the second (V2) used the OSDI as well as the Symptoms Assessment Questionnaire in Dry Eye (SANDE) II and CDES-Q. The researchers performed clinical evaluations at each visit, and the V2 took place 90 days after V1. The researchers found that there was a significant reduction in symptoms (P =.0021) as reflected on OSDI, SANDE II, and CDES-Q, and there was a significantly lower SANDE II when patients answered “better” for CDES-Q1 as compared to the other options. Patients’ questionnaire results were then compared with the changes observed in clinical signs.

Participants of the study included patients older than 18 years (mean age 56.0 years + 14.5 years) with varying severities of DED-related symptoms, with OSDI scores greater than 12 points. The majority of participants had a main diagnosis of evaporative or hyposecretory DED, or both, while the rest had a diagnosis of either chronic ocular graft vs host disease, blepharitis, or ocular rosacea.

The researchers explain that, while the SANDE II is another questionnaire that documents changes in symptoms, the majority of existing tools, such as the OSDI, are unable to do so. While the OSDI was designed to evaluate symptoms in a specific timeframe, the SANDE II, as well as the new CDES, are meant to track changes resulting from specific interventions. However, the study clarifies that the CDES should not be used for the diagnosis of DED

The study’s limitations include small sample size and the lack of a control group and other components of an experimental study.

“In future studies, it would be necessary to control several factors that may influence the way in which patients respond to questionnaires, such as age, education level, etc.,” the study explains. “Finally, it would be necessary to establish in future studies the measurement fundamentals for this new tool, such as test-retest repeatability.”


Pinto-Fraga J, Calonge M, Enríquez-de-Salamanca A, Fernández I, González-García MJ, Steven P. Development of a questionnaire for detecting changes in dry eye disease-related symptoms. Eye Contact Lens. 2021;47(1):8-14. doi:10.1097/ICL.0000000000000693.