The Effects of Changing Light Levels on Contrast Sensitivity in Patients With Glaucoma

Study Overview
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Brief Summary
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The study is a prospective observational study where participants will be recruited from the Ophthalmology department (Outpatient department, Eye Casualty). Only one research visit will be required. Participants will be asked to fill in a set of questionnaires (Visual Functioning Questionnaire-15(61), Low Luminance Questionnaire(62)) assessing their quality of life and vision and their full medical history will be collected. Then they will have their contrast sensitivity tested under various light conditions. If a recent visual field test is not available, that might be performed as part of the study.

Detailed Description
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The purpose of our, real world study is to explore contrast sensitivity differences after changes in ambient light setting in patients with glaucoma compared with controls (patients with ocular hypertension). Participants will be asked to read a Pelli- Robson chart under photopic (bright light conditions) and mesopic (intermediate light conditions); followed by scotopic conditions (dim light conditions). This chart is a fast, easy, and effective way to measure spatial contrast sensitivity with reliable and reproducible results(60). This study will therefore help clinicians gain more insight into glaucoma related disability and provide a possible additional tool to visual field testing in patients with advanced glaucoma where VF testing may be hampered by floor effects.

Official Title
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The Effects of chaNging LIGHT Levels on Contrast sENsitivity in Patients With Glaucoma

Conditions
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Glaucoma

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: • Male or Female, aged 40 years or above. Diagnosis of glaucoma (including primary open angle glaucoma, pigment dispersion syndrome, pseudoexfoliation, normal tension glaucoma, chronic angle closure glaucoma, narrow angle glaucoma) or ocular hypertension Willing and able to give informed consent for participation in the study. Best Corrected Visual Acuity equal or better than 6/12 as measured with the Snellen Chart Exclusion Criteria: • Neovascular, uveitic, acute angle closure glaucoma Non-glaucomatous ocular disease such as AMD, Diabetic retinopathy, Inherited eye diseases Visually significant cataracts (Distance VA ≤ 6/12 (0.30 LogMAR) and grade ≥ grade 2 nuclear sclerosis.) Current use of miotic glaucoma medication Incisional or laser eye surgery within 3 months of enrolment Severely impaired cognition Self-reported physical ability limiting function (e.g. stroke) Unreliable visual fields (SITA Standard or SITA Fast: fixation losses >20% or false-positive errors >33% or false-negative errors >33%)

Ages Eligible for Study
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Minimum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| vision-related quality of life in patients with glaucoma | assessed using the the visual functioning questionnaire - 25 questionnaire | 1 day study visit | 
| Visual function | assessed using the low luminance questionnaire | through study completion, an average of 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To correlate visual impairment with contrast sensitivity results | measured with Quality of Life questionnaires (Visual Functioning Questionnaire-25, Low Luminance Questionnaire) | through study completion, an average of 1 year | 
| Contrast Sensitivitiy | Participants' contrast sensitivity will be tested under photopic (bright light conditions), mesopic (intermediate light conditions) and/or scotopic conditions (dim light conditions). | through study completion, an average of 1 year |