Intensive care units (ICU) face a significant challenge in facilitating patient-caregiver and family-caregiver communication. As a result of these fluctuations, standard comprehension tests are not feasible for use with patients. Researchers wanted to see how well eye-tracking technologies might automate an oral comprehension test for intensive care unit patients. About 60 healthy volunteers and 53 intensive care unit (ICU) patients participated in prospective bi-centric cohort research. Participants took an oral comprehension test while wearing eye-tracking equipment, and investigators noted their performance and other relevant features. The entire diagnostic procedure took about 3 minutes. About 48 patients (92%) were given invasive ventilation during the study. The median correct response rate was much higher among healthy volunteers (93% [interquartile range 87, 100]) than it was among patients (33% [20, 67]). Age and the absence of a bachelor’s degree were also associated with a decrease in correct responses across the board for both groups (67% [27, 80] vs. 27% [20, 38] among patients and 93% [93, 100] vs. 87% [73, 93] among healthy volunteers, below and above 60 years of age, respectively). Patients’ rates of getting questions right decreased as disease severity increased. The eye-tracking adaptation of the comprehension test is simple and quick to administer to patients in the intensive care unit, and the results appear consistent with the various hypothesized levels of comprehension.