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.
Aim 1: To determine whether differences exist between people with healthy eyes and patients with POAG in seeing under dim illumination (Low Luminance Questionnaire) and to determine whether such differences are associated with life space. Aim 2: To determine whether differences exist between people with healthy eyes and patients with POAG in seeing under dim illumination (objective measures of visual function) and to determine whether such differences are associated with life space.
Study Type
OBSERVATIONAL
Enrollment
100
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.
This 32-item questionnaire is interested in finding out problems that involve vision under different lighting conditions or feelings that people have about your vision under different lighting conditions.
Participants will be presented with visual targets of different contrast under dim illumination and asked to report when they see the target.
Sensitivity in the central visual area will be assessed under dim illumination
Participants will be asked to look at a fixation target and the density of their macular pigment will be assessed.
After adapting to a dark environment, participants will be exposed a bright flask of light. the time needed for them to recover their sensitivity will be measured.
University of Alabama Birmingham
Birmingham, Alabama, United States
RECRUITINGAssessment 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.
Time frame: 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.
Time frame: 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/
Time frame: 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).
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: Through study completion, an average of 1 year
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