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.
Patients with glaucoma must meet all of the inclusion criteria to participate in this study.
Patients diagnosed with primary open-angle glaucoma (POAG), as indicated by Humphrey Visual Field (HVF) mean deviation (VFMD) scores better than -12 dB in at least one eye during their most recent clinic visit.
Patients having spared central vision.
Patients aged 45 to 75 years old.
Participants with myopia exhibiting a refractive error exceeding -8.00 diopters (D)
Participants with a history of complicated previous intraocular surgery
Participants taking alpha-adrenergic agonist eye drops or other systemic medications or drugs that could affect the pupillary response
Participants with any past or current ocular condition (i.e., age-related retinal diseases (e.g., age-related macular degeneration), retinal pigment epithelium diseases (e.g., Best's disease), diabetic retinopathy, or other optic or generalized neuropathies, significant ocular trauma, or any eye condition affecting fixation (eg. Nystagmus)).
Crossover
Full-spectrum light exposure
Other interventionParticipants 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).
Standard indoor light exposure (Control)
Other interventionParticipants 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).
Subjective Sleep Quality
Sleep quality is assessed using the Pittsburgh Sleep Quality Index (PSQI), a validated self-report questionnaire measuring subjective sleep quality, sleep latency, duration, efficiency, disturbances, use of sleep medication, and daytime dysfunction over the past month. Higher scores indicate poorer sleep quality.
Subjective Daytime Sleepiness
Daytime sleepiness is assessed using the Epworth Sleepiness Scale (ESS), a validated questionnaire evaluating the likelihood of dozing in common daytime situations. Higher scores indicate greater daytime sleepiness.
Depressive Symptoms
Depressive symptoms will be assessed using the Patient Health Questionnaire-9 (PHQ-9), a validated self-report questionnaire measuring the frequency and severity of depressive symptoms over the past two weeks. Higher scores indicate greater depressive symptom severity.
Global Cognitive Function
Global cognitive function will be assessed using the Montreal Cognitive Assessment (MoCA), a standardized screening tool evaluating executive function, attention, memory, language, and visuospatial abilities.
Anticipatory Pupil Size
Anticipatory pupil size will be assessed using an eyetracker measuring pupil size throughout PVT and oddball tasks. Anticipatory pupil size will be quantified by median pupil size prior stimulus onset.
Hit Rate
Hit Rate assessed using a laboratory-based auditory oddball task. Auditory tones will be presented via headphones while participants view a fixation display on a monitor and respond using a keyboard. Hit rate is defined as the proportion of correctly detected target tones relative to the total number of target tones presented during the auditory oddball task.
False Alarm Rate
False alarm rate is assessed using a laboratory-based auditory oddball task. Auditory tones will be presented via headphones while participants view a fixation display on a monitor and respond using a keyboard. False alarm rate is quantified as the proportion of responses made to non-target tones relative to the total number of non-target tones presented during the auditory oddball task.
Correct Rejection Rate
Correct rejection rate is assessed using a laboratory-based auditory oddball task. Auditory tones will be presented via headphones while participants view a fixation display on a monitor and respond using a keyboard. Correct rejection rate is defined as the proportion of non-target tones for which no response is made (i.e., correctly ignored non-target tones) relative to the total number of non-target tones presented during the auditory oddball task.
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National University of Singapore
Lead sponsor
Singapore National Eye Centre
Collaborator
Singapore Eye Research Institute
Collaborator
National University Hospital, Singapore
Collaborator
