Author: Lisa O’Mary
Medscape
Like many hospice clinicians, Jung Hun Kang, MD, PhD, had noticed the disappearance of the corneal reflex in his dying patients. But unlike most, he decided to investigate.
His new study, published in BMJ Supportive and Palliative Care, suggests the loss of this involuntary blink response can predict death within 24 hours. The findings offer clinicians a simple new tool to help families navigate the final hours of a loved one’s life by answering their most critical question: How long?
“In Korea, family members often place great importance on being present at the moment of death,” said Kang, director of the hospice center at Gyeongsang National University Hospital in South Korea. “That often leads to difficult and urgent questions about how much time remains. In practice, I often felt the limits of existing clinical signs when trying to answer those questions.”
While the medical community has long used the corneal reflex to confirm brain death in comatose patients, this study is the first to systematically link it to the timing of imminent death. Clinicians typically monitor a constellation of signs — death rattle, peripheral cyanosis, mandibular breathing — which have high specificity when present but low sensitivity; many patients die without ever showing them.
Identifying these signs carries a 95% probability of death within 48 hours. Kang’s new research suggests the corneal reflex could narrow that window.
A Simple Test
In the study, trained nurses assessed corneal reflex three times a day among 112 hospice patients with advanced cancer and a life expectancy of 1-2 weeks. The median age was 73.5 years; 110 participants died within 7 days.
Nurses approached from the side to avoid triggering a visual response and gently touched the cornea with a sterile cotton wisp or gauze strand. Data were coded as follows:
- Intact: Brisk eyelid closure
- Diminished: Slow or incomplete closure
- Absent: No eyelid movement
Asymmetrical reflex, such as one side intact and one diminished, was also marked “diminished.” (There were no instances of one absent and the other intact.)
Patients with an absent reflex had 5.48 times higher odds of death within 24 hours than those whose reflex remained intact or diminished. The 24-hour mortality rate for those with absent reflex was 70.7%.
“Absence of the reflex may strongly support a prediction of imminent death, but preservation of the reflex does not rule it out,” Kang said, noting the challenge of “moderate sensitivity” that affects many end-of-life indicators. “Loss of the corneal reflex may reflect progressive deterioration of brainstem function as part of the natural dying process.”
Out of 13 potential indicators, a Richmond Agitation-Sedation Scale (RASS) score of -4 or -5 (indicating deep sedation) was the most sensitive. Combining RASS with corneal reflex may be especially useful, Kang said. “RASS can help identify patients entering the dying phase, and the corneal reflex may help physicians make a more specific assessment.” Among patients with -4 or -5 RASS, 71.2% of those whose corneal reflex was absent died within 24 hours, compared to 37.1% of those whose reflex remained.
Clinical Considerations
Controlled by part of the brainstem known as the pons, the corneal reflex was established over half a century ago as a marker for brain death. Applying it in the context of imminent death is a novel shift, said David Hui, MD, director of research for supportive and palliative care at MD Anderson Cancer Center in Houston.
Hui, who was not involved in the study, called the corneal reflex results comparable in sensitivity and specificity to other “late signs” but noted the small sample size and potential selection bias. The study was done only in patients with a RASS of -3 or lower to avoid causing discomfort to more conscious patients.
“Absent corneal reflex and non-reactive pupil both point to decreased brainstem response,” Hui said. “It would be interesting to see how many patients had both or just one or the other, and if the addition of corneal reflex improved prediction.”
On the Horizon
A multi-center follow-up study in a more diverse population is planned, Kang said. He envisions the corneal reflex test as a confirmatory step following RASS and peripheral cyanosis (bluish discoloration).
With many countries and jurisdictions changing euthanasia and end-of-life legal frameworks, demand for bedside prognostic tools may be rising. But ethical hurdles remain.
“Translational research in this population faces unique ethical complexities,” Kang said. “The dignity and comfort of the dying patient must always take precedence over invasive sampling or procedures.” He hopes AI may help detect subtle patterns that might escape bedside clinicians.
“Improving care in the final hours of life is just as important as prolonging survival,” Kang said. “The better we become at recognizing imminent death, the better we can support a more peaceful and dignified experience for patients and families.”