Eye Movements to Predict Post-Operative Delirium (EYE-POD)

Predicting Post-operative Delirium Using Eye Movements: a Pilot Study

Postoperative delirium (POD) is a common complication in older adults undergoing surgery, lacking objective and noninvasive diagnostic methods. This trial aims to evaluate the feasibility and prognostic performance of Eye movements (EM) as a risk biomarker for the development of POD in older patients undergoing moderate- to high-risk surgery. The investigators hypothesize that EM tracking will accurately predict POD, potentially optimizing early intervention and patient outcomes.

Study Overview

• Status: Enrolling by invitation
• Conditions: Post Operative Delerium; Post Operative Cognitive Dysfunction

Detailed Description

This prospective trial evaluates the integration of automated eye movement assessments as a novel, noninvasive risk biomarker for postoperative delirium (POD) in older adults. Upon enrollment, trained clinical staff will collect baseline demographic data and clinical characteristics. Chronic medical burden will be quantified using the Charlson Comorbidity Index (CCI). To establish baseline cognitive function and control for preexisting cognitive impairment, all participants will undergo the Montreal Cognitive Assessment (MoCA).

Technical Protocol for Eye Movement Recording

Preoperatively, participants will complete an automated eye movement tracking protocol consisting of two distinct paradigms:

Prosaccadic Task: Utilized to measure specific ocular motor parameters, including saccadic latency, velocity, and accuracy.

Free Visual Exploration Task: Utilized to capture free-gaze metrics and spatial distribution patterns.

All eye-tracking data will be recorded using automated software to ensure objectivity and reproducibility.

Postoperative Monitoring Following the surgical procedure, patients will be systematically monitored for the development of POD. The Confusion Assessment Method (CAM) will be administered by trained examiners twice daily (morning and evening) for the first three postoperative days (72 hours) to detect and document the incidence and severity of delirium.

Statistical and Predictive Objectives

The collected data will be analyzed to fulfill three primary scientific objectives:

1. Parameter Association: To identify which specific preoperative eye-tracking metrics (latency, velocity, accuracy, or free-gaze variables) demonstrate a statistically significant association with the incidence of POD.
2. Diagnostic Performance: To calculate the sensitivity and specificity of these distinct preoperative eye movement parameters for predicting POD development.
3. Incremental Predictive Value: To evaluate whether adding preoperative eye-tracking measurements to a standard clinical prediction model (comprising age, sex, CCI, and MoCA scores) significantly improves the model's overall predictive performance and risk stratification capabilities.

• Study Type: Observational
• Enrollment (Estimated): 40

Contacts and Locations

Study Locations

• Chile
  • Santiago Metropolitan
    • Santiago, Santiago Metropolitan, Chile, 8320000
      • Hospital Clínico de la Universidad de Chile

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Older adult patients scheduled for moderate- to high-risk surgeries at the Hospital Clínico de la Universidad de Chile. The cohort is drawn from the elective surgical scheduling pool of the institution, aiming for a balanced distribution across biological sex and age ranges within the target demographic.

Description

Inclusion Criteria:

• Patients aged 70 years or older.
• Scheduled for moderate- to high-risk elective surgery, defined as a procedure requiring a postoperative hospital stay of at least 3 days.
• Able to provide signed, written informed consent.

Exclusion Criteria:

• Presence of delirium at baseline admission, evaluated via the Confusion Assessment Method (CAM).
• Use of neuroleptic/antipsychotic medications within the past 6 months.
• Prior history of dementia (including Alzheimer's disease, vascular dementia, or mild cognitive impairment).
• History of encephalopathy.
• Psychiatric disorders presenting with psychosis.
• Brain injury with neurological sequelae (e.g., prior stroke, traumatic brain injury).
• Visual acuity is insufficient to complete the automated eye-tracking tasks.
• Illiteracy.
• Non-Spanish speakers.
• Concurrent participation in any other clinical trial.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

No Intervention: Control (Usual care) + Eye movement recording; This is a prospective, observational cohort study designed to evaluate the prognostic accuracy of a preoperative eye-tracking biomarker protocol for predicting postoperative delirium (POD). All eligible participants are recruited from a cohort of patients already scheduled for moderate- to high-risk elective surgery at the University of Chile Clinical Hospital. The study procedures (baseline clinical data collection, Charlson Comorbidity Index, MoCA, and automated eye-tracking tasks) are strictly observational and diagnostic. The eye-tracking results are recorded for research purposes only and do not alter standard perioperative care, surgical management, or anesthetic techniques. Patients are subsequently followed into the postoperative period to monitor the incidence of POD via twice-daily Confusion Assessment Method (CAM) evaluations during the first three postoperative days.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of postoperative delirium (POD).	The presence or absence of postoperative delirium will be assessed using the Confusion Assessment Method (CAM). Patients will be classified as "POD" or "No POD" based on the CAM diagnostic algorithm.	From the day of surgery up to postoperative day 3, patients were assessed twice daily.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Preoperative Baseline Cognitive Status	Total score on the Montreal Cognitive Assessment (MoCA) to determine baseline global cognitive function. The score ranges from 0 to 30, with lower scores indicating greater cognitive impairment.	At preoperative baseline (day of surgery or day before).
Preoperative Comorbidity Burden	Score on the Charlson Comorbidity Index (CCI) to quantify the participant's baseline medical comorbidity burden and pre-existing health conditions.	At preoperative baseline (day of surgery or day before)
Preoperative Saccadic Latency	The time taken from the appearance of a visual target to the initiation of the participant's saccadic eye movement during the prosaccadic task (milliseconds).	At preoperative baseline (day of surgery or day before)
Preoperative Saccadic Velocity	The peak speed of the participant's eye movement when moving towards the visual target during the prosaccadic task (degrees per second).	At preoperative baseline (day of surgery or day before).
Preoperative Free Viewing Number of Fixations	The absolute count of discrete gaze fixations made by the participant during the free visual exploration task (number of fixations)	At preoperative baseline (day of surgery or day before).
Preoperative Free Viewing Saccade Length	The average spatial distance between fixations in the participant's eye movements during the free visual exploration task (degrees of visual angle).	At preoperative baseline (day of surgery or day before).
Hospital Length of Stay	Total hospital stay from the day of surgery until official hospital discharge.	Up to 30 days post-surgery.
All-Cause Mortality	Total number of participant deaths from any cause, verified via hospital electronic medical records or direct follow-up contact.	At 30 days post-surgery.

Collaborators and Investigators

• Sponsor: University of Chile
• Investigators: Principal Investigator: Ivan Plaza-Rosales, PhD, University of Chile

Publications and helpful links

General Publications

• Al-Hindawi A, Vizcaychipi M, Demiris Y. A Dual-Camera Eye-Tracking Platform for Rapid Real-Time Diagnosis of Acute Delirium: A Pilot Study. IEEE J Transl Eng Health Med. 2024 May 7;12:488-498. doi: 10.1109/JTEHM.2024.3397737. eCollection 2024.
• van der Kooi AW, Rots ML, Huiskamp G, Klijn FA, Koek HL, Kluin J, Leijten FS, Slooter AJ. Delirium detection based on monitoring of blinks and eye movements. Am J Geriatr Psychiatry. 2014 Dec;22(12):1575-82. doi: 10.1016/j.jagp.2014.01.001. Epub 2014 Jan 4.
• Chapin BA, Kimmett F, Garvan C, Tighe P, Dekosky S, Williamson JB, Price CC. Preoperative Visual Attention Performance Predicts Postoperative Delirium. Alzheimers Dement. 2025 Jan 3;20(Suppl 3):e091620. doi: 10.1002/alz.091620. PMCID: PMC11710506.

Study record dates

Study Major Dates

• Study Start (Actual): August 6, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): March 1, 2027

Study Registration Dates

• First Submitted: August 3, 2026
• First Submitted That Met QC Criteria: September 1, 2026
• First Posted (Actual): September 8, 2026

Study Record Updates

• Last Update Posted (Actual): September 8, 2026
• Last Update Submitted That Met QC Criteria: September 1, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Eye movements; Eye-tracking; Post operative delirium
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Postoperative Complications; Pathologic Processes; Confusion; Neurobehavioral Manifestations; Neurocognitive Disorders; Delirium; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Emergence Delirium
• Other Study ID Numbers: 159526

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No