Daniel Joyce, PhD


Daniel Joyce, PhD

Name of Institution:

Stanford University, Stanford, CA

Project Title:

Pupil-based biomarkers of Parkinson’s disease (PD)

Investigator Bio:

Dr. Joyce received his PhD in Vision Science from the Queensland University of Technology, Australia, before joining the School of Medicine at Stanford University. Dr. Joyce investigates the mechanisms by which we sense light, and their influence on human behaviors including circadian rhythms and sleep, cognitive function and overall well-being.


This research will evaluate the link between abnormal light sensing pathways and PD


Sleep and circadian rhythm disruption are common in PD and can occur before motor symptoms appear. Their causes however, are poorly understood. We have recently shown that people with PD have reduced light sensing in the pathways that are critical for controlling circadian rhythms and sleep, and that these deficits can be detected by assessing the pupil’s response to light.


Using the pupil response to light as a rapid and non-invasive biomarker of how well these light sensing pathways function, this study will evaluate how image forming vision (for example, color vision) and in particular how non-image forming vision (e.g. light that alters physiological states and sleep/wake timing) is associated with PD duration as well as motor and non-motor symptom severity.

Relevance to Diagnosis/Treatment of Parkinson’s disease:

This study will help us understand the causes of sleep and circadian disruption in PD and allow the formulation of more effective ways to improve quality of life. This study may also help in developing a test of pupillary function as a simple biomarker of PD.