Brief Summary

Mobility refers to a person's purposeful movement through the environment from one place to another and can be conceptualized as a continuum from bed bound (immobility) on one extreme to making excursions to distant locations on the other extreme. Primary open-angle glaucoma (POAG) is a chronic, progressive optic neuropathy that can lead to gradual loss of vision in the peripheral field and central vision. Older adults with POAG have an increased risk for motor vehicle collisions and falls. Moreover, existing studies suggest that patients with POAG exhibit more postural sway while standing as measured by a balance platform and also tend to walk more slowly than those who are normally sighted and free of ocular disease. While these disturbances likely influence mobility, there has been little research directly assessing the impact of POAG on mobility. This study will assess the impact of POAG on life space (one aspect of mobility) and will determine whether difficulties with life space are associated with difficulties experienced under conditions of dim lighting.

Trial Health

On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment

100

participants targeted

Target at P50-P75 for all trials

Timeline

1mo left

Started Jun 2019

Longer than P75 for all trials

Geographic Reach

1 country

1 active site

Status

recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

7 years study duration

Study Progress99%

Jun 2019May 2026

Study Start

First participant enrolled

June 1, 2019

Completed

12 months until next milestone

First Submitted

Initial submission to the registry

May 12, 2020

Completed

8 days until next milestone

First Posted

Study publicly available on registry

May 20, 2020

Completed

6 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

May 30, 2026

Expected

Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

May 30, 2026

Last Updated

September 12, 2025

Status Verified

September 1, 2025

Enrollment Period

7 years

First QC Date

May 12, 2020

Last Update Submit

September 5, 2025

Conditions

Primary Open Angle Glaucoma

Outcome Measures

Primary Outcomes (8)

Assessment of life space measured with the Life Space Questionnaire
The Life Space Questionnaire is a 9-item questionnaire that assesses how much a person gets out and about and the spatial extent of the person's typical life space, i.e., what is the usual range of places in which the person engages in activities within the designated time frame. Patients are asked to respond either Yes or No.
Through study completion, an average of 1 year
Assessment of vision under low luminance conditions
The Low Luminance Questionnaire is a 32-item questionnaire that assesses how participants see under dim illumination and how well they can perform different tasks (e.g. reading, driving). Patients are asked to select a response among different choices on a Likert scale that ranges from 1 to 5, 1 to 6, 1 to 7, or 1 to 8 depending on the question. A response of "1" indicates that the participant experiences no difficulty while increasingly higher numbers indicate increasing amounts of difficulty.
Through study completion, an average of 1 year
Differences in contrast sensitivity functions between controls and patients
Participants will be presented with targets of different spatial frequency at different contrasts. Their sensitivity at each spatial frequency will be recorded/
Through study completion, an average of 1 year
Differences in dark adaptation between controls and patients
Once participants have adapted to a dark environment, they will be exposed to a bright flash of light. The time needed to recover their visual sensitivity will be measured (rod-intercept time).
Through study completion, an average of 1 year
Differences in visual sensitivity under dim illumination between controls and patients
Participants will be presented with targets at different locations in their visual fields under dim illumination.
Through study completion, an average of 1 year
Differences in Macular Pigment Optical Density between controls and patients
Participants will fixate on a target while their MPOD is assessed. The MPOD is measured using the Heidelberg optical coherence tomography (OCT) MPOD module. Two different light sources are directed to the back of the eye. The light is reflected back and the OCT/MPOD computes the difference in the reflectance of the two lights which is an estimate of the density of macular pigment.
Through study completion, an average of 1 year
Assessment of the relationship between each the measure of visual function and life space
The relationship between each of the measures of visual function (dark adaptation, contrast sensitivity functions, visual fields under dim illumination, and MPOD) and life space (Life Space Questionnaire will be assessed.
Through study completion, an average of 1 year
Assessment of the relationship between each the measure of visual function and self-reported visual function under dim illumination
The relationship between each of the measures of visual function (dark adaptation, contrast sensitivity functions, visual fields under dim illumination, and MPOD) and self-reported visual performance under dim illumination (Low Luminance Questionnaire) will be assessed.
Through study completion, an average of 1 year

Study Arms (2)

Primary Open-Angle Glaucoma

Patients diagnosed with primary open-angle glaucoma.

Diagnostic Test: Life Space QuestionnaireDiagnostic Test: Low Luminance QuestionnaireDiagnostic Test: Contrast sensitivity under dim illuminationDiagnostic Test: Visual field under dim illumination (MAIA)Diagnostic Test: Macular Pigment Optical Density (MPOD)Diagnostic Test: Dark Adaptation

Control

Participants with healthy eyes.

Interventions

Life Space QuestionnaireDIAGNOSTIC_TEST

This 9-item questionnaire is interested in finding out how much a person gets out and about and the spatial extent of the person's typical life space, i.e., what is the usual range of places in which the person engages in activities within the designated time frame.