How glaucoma-related changes in light sensing affect sleep, mood, alertness, and thinking

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This mixed observational and interventional study will compare 60 adults with bilateral primary open‑angle glaucoma to 60 age‑matched healthy controls to measure non‑visual responses to light. Participants undergo eye exams, questionnaires, cognitive and alertness tests, and physiological measures of light sensitivity, followed by short exposures to full‑spectrum versus standard indoor lighting. The design aims to link ipRGC‑related light sensitivity to sleep, mood, alertness, and cognitive performance and to test whether altering indoor light improves these outcomes. Outcomes will be compared between groups and within individuals before and after light exposure.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* 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.
  * Patients with a best-corrected visual acuity better than 6/12
  * English-speaking patients

Healthy controls must meet all of the inclusion criteria to participate in this study:

* Participants aged 50 to 70 years old.
* Participants with a best-corrected visual acuity better than 6/12
* Normal ophthalmic examination
* English-speaking participants

Exclusion Criteria:

* All subjects (patients and controls) meeting any of the exclusion criteria at baseline will be excluded from participation:

  * 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)).
  * Participants diagnosed with cataracts at NS3+ (Nuclear Sclerosis) and above, as well as those with Posterior Subcapsular (PSC) cataracts
  * Participants with clinically diagnosed psychiatric or neurologic disorders, including cognitive impairment or dementia
  * Participants with diagnosed mood disorders
  * Participants engaged in night shift work within the past three months, are currently using sleeping pills, or have recently travelled across timezones within a month prior to the study
  * Participants with obstructive sleep apnea
  * Participants with abnormal auditory function
  * Participants with impaired color vision
  * Pre-menopausal women (last menstrual period \< 1 year) (If applicable)
  * Patients having unilateral glaucoma, congenital glaucoma, non-glaucomatous optic neuropathy, abnormal central vision
  * Diabetics on treatment

Where it's running

• Singapore National Eye Center
  Singapore, Singapore Recruiting
• National University Hospital
  Singapore, Singapore Not yet recruiting

Study contacts

• Principal investigator: Raymond P. Najjar, PhD — National University of Singapore
• Study coordinator: Daniella Mahfoud, MSc.
• Email: daniella.mahfoud@u.nus.edu
• Phone: +65 65165474

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.