Electroretinography: Investigation of a Protocol Change

Study Overview
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Brief Summary
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The study evaluates whether an eye test called an electroretinogram (ERG) can be shortened and still produce the same diagnostic results. The results of this study may allow test times to be reduced which will have benefits such as improved patient compliance during shorter testing and increased clinic efficiency.

Detailed Description
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A full-field electroretinogram (ERG) is a standardised eye test undertaken in specialist hospital clinics. ERGs are useful for diagnosing and monitoring retinal diseases. The retina is stimulated by showing patients flashes of light and the resulting electrical response from the eye is recorded using delicate electrodes that touch the surface of the eye. For the first section of the test, patient's eyes are allowed to adjust to the dark to ensure the parts of the retina responsible for seeing in dimly-lit conditions are being tested. The international ERG Standard says patients must sit in the dark for 20 minutes. The investigators have evidence to suggest the test may be equally useful after only 10 minutes in the dark. The investigators plan to compare ERGs recorded from patients who have spent only 10 minutes in the dark with ERGs recorded from the same patients after the full 20 minutes in the dark. If the difference is suitably small, as found in a preliminary study of healthy individuals, it could be justifiable to shorten the routine patient protocol. Subjects for this study will be recruited from the adult population routinely attending for an outpatient ERG test. During their routine ERG test, 10 minutes into the 20 minute wait in the dark, the investigators propose recording an additional, identical set of ERG tests. This will not add extra time to the clinical test. Participants will not need any follow-up for the research study. The study requires 262 patients to test the hypothesis, and the investigators estimate this will take about 5-6 months.

Official Title
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Investigation of a Protocol Change (Shorter Dark-adaptation) on the Electroretinogram (ERG) in an Adult Patient Population (SHERG)

Conditions
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Dark-adapted ERG

Intervention / Treatment
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* Diagnostic Test: Electroretinography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients referred to the adult visual electrophysiology service regardless of clinical condition, and who require dark-adapted electroretinography as part of their appointment Male or female All ethnicities Exclusion Criteria: Patients less than 18 years old Patients who might have difficulties understanding the participant information provided (for example, those patients requiring a translator, or who have learning difficulties) Patients with photosensitive epilepsy Patients appointed for clinical testing urgently, or via telephone, who will not have had an opportunity to receive and review the participant information sheet ahead of the clinical appointment.

Ages Eligible for Study
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Minimum Age: 18 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Adult patients<br>Adult patients attending hospital for clinical visual electrophysiology. | Diagnostic Test: Electroretinography<br>* An additional electroretinogram performed after 10 minutes of dark adaptation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of classification for ERG following 10 minute dark adaptation | The rate of classification (normal vs abnormal) for testing conducted after 10 minutes of dark adaptation. | (During first & only study visit) Dark-adapted ERG test following 10 minutes of dark adaptation | 
| Rate of classification (normal vs abnormal) for ERG following 20 minute dark adaptation | The rate of classification (normal vs abnormal) for testing conducted after 20 minutes of dark adaptation. | (During first & only study visit) Dark-adapted ERG test following 20 minutes of dark adaptation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Response amplitude after 10 minutes | Measurement of the amplitude of responses following 10 minutes of dark adaptation. | (During first & only study visit) Dark-adapted ERG test following 10 minutes of dark adaptation | 
| Response amplitude after 20 minutes | Measurement of the amplitude of responses following 20 minutes of dark adaptation. | (During first & only study visit) Dark-adapted ERG test following 20 minutes of dark adaptation | 
| Response timing | Measurement of the amplitude of responses following 10 minutes of dark adaptation. | (During first & only study visit) Dark-adapted ERG test following 10 minutes of dark adaptation | 
| Response timing | Measurement of the amplitude of responses following 20 minutes of dark adaptation. | (During first & only study visit) Dark-adapted ERG test following 20 minutes of dark adaptation | 
| Response variability | Measurement of the variability of responses following 10 minutes of dark | (During first & only study visit) Dark-adapted ERG test following 10 minutes of dark adaptation | 
| Response variability | Measurement of the variability of responses following 20 minutes of dark | (During first & only study visit) Dark-adapted ERG test following 20 minutes of dark adaptation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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electroretinogram, ERG, dark-adaptation, ophthalmology, electrophysiology, ISCEV, electroretinography, scotopic