Altered Non-Visual Photoreception in Patients With Glaucoma: Impacts on Sleep, Alertness, Mood, and Cognition

Summary

The goal of this study is to understand how light sensitivity in the eye affects sleep, mood, alertness, and cognition in adults with glaucoma compared to healthy individuals aged 45-75 years.

The main questions it aims to answer are:

1. Do patients with glaucoma experience poorer sleep, mood, alertness, and cognitive function than age-matched healthy adults?
2. Are these changes related to reduced light sensitivity in special retinal cells called intrinsically photosensitive retinal ganglion cells (ipRGCs), lost in glaucoma?
3. Can exposure to safe, full-spectrum indoor light help improve these functions?

Researchers will compare patients with glaucoma and age-matched healthy controls to see if differences in light sensitivity can explain changes in non-visual light responses (i.e., sleep, mood, alertness, and cognition) and whether full-spectrum light exposure can enhance alertness and wellbeing.

Participants will:

1. Complete eye exams and baseline questionnaires about their sleep, daytime sleepiness, mood, and wellbeing.
2. Wear a wrist-worn device for 8-16 days to record their sleep patterns and light exposure.
3. Visit the laboratory for cognitive and attention tests following exposure to two lighting conditions (randomized, cross-over):

* Standard indoor light (\~300 lux)
* Full-spectrum light (\~1000 lux)

This study will help researchers understand how glaucoma affects the brain beyond vision and explore whether light-based interventions can improve quality of life for people living with glaucoma.

Conditions

• Glaucoma

Interventions

OTHER

Full-spectrum light exposure

Participants will be exposed to a full-spectrum white light designed to replicate the spectral quality of natural daylight while maintaining safe, indoor intensity levels. The light source delivers an illuminance of approximately 1000 lux and is free of ultraviolet and infrared wavelengths. Each participant will undergo two periods of light exposure, intermittently, during the laboratory visit at the Eye N' Brain Research Platform (NUS).

OTHER

Standard indoor light exposure (Control)

Participants will be exposed to a standard indoor light with an illuminance of approximately 300 lux. Each participant will undergo two periods of light exposure, intermittently, during the laboratory visit at the Eye N' Brain Research Platform (NUS).

Sponsors & Collaborators

• Singapore National Eye Centre

  collaborator OTHER_GOV

• Singapore Eye Research Institute

  collaborator OTHER

• National University Hospital, Singapore

  collaborator OTHER

• National University of Singapore

  lead OTHER

Principal Investigators

• Raymond P. Najjar, PhD · National University of Singapore

Study Design

Allocation

RANDOMIZED

Purpose

SUPPORTIVE_CARE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

45 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-09-05

Primary Completion

2026-10-31

Completion

2026-12-31

Countries

• Singapore

Study Locations