Adaptation Time Required for the Optimisation of Maia Microperimetry Visual Field Testing
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|ClinicalTrials.gov Identifier: NCT02729818|
Recruitment Status : Completed
First Posted : April 6, 2016
Last Update Posted : November 8, 2018
Microperimetry is a relatively new and extremely sensitive method of assessing visual function. It projects light stimuli onto a defined area of the retina to map retinal perceptual thresholds. Participants look at a focal point and press a button to indicate when they have seen a light stimulus. The stimuli vary in intensity to find the participant's visual sensitivity.
Microperimetry is carried out in low light conditions. Before testing, participants must adapt to the low light conditions in a process called 'dark adaptation.' Currently there is no consensus on the optimal time needed for dark adaptation. Investigators know that visual sensitivity differs in differing light conditions. Failing to sufficiently dark-adapt may therefore adversely affect test results.
The aim of this study is to establish the optimal length of dark adaptation for microperimetry performance in healthy volunteers. On day 1, participants will undergo training field tests to reduce a learning effect affecting the results. Tests will then be performed following 5 mins adaptation, 10 mins adaptation and 30mins adaptation, On day 2, participants will perform testing following no adaptation time, 15 mins adaptation, and 20 mins adaptation. Statistics will be used to determine the effect of adaptation time on average threshold measures.
|Condition or disease|
|Study Type :||Observational|
|Actual Enrollment :||40 participants|
|Official Title:||Adaptation Time Required for the Optimisation of Maia Microperimetry Visual Field Testing|
|Actual Study Start Date :||February 2016|
|Actual Primary Completion Date :||September 2017|
|Actual Study Completion Date :||September 2017|
- Change in average threshold of tests following different dark adaptation periods will be compared. [ Time Frame: Different time intervals for adaptation prior to testing; 0 minutes, 5, 10, 15, 20 and 30 minutes on day 1 and day 2. ]The average threshold for each test is detailed on the microperimetry printout and is measured in dB. This will be measured by testing following each time interval specified.
- Change in fixation stability, as defined by the area in which 95% of the fixation points for any specific test fall, following different dark adaptation periods will be compared. [ Time Frame: Different time intervals for adaptation prior to testing; 0 minutes, 5, 10, 15, 20 and 30 minutes on day 1 and day 2 ]The fixation stability for each test is detailed on the microperimetry printout and is measured in degrees for the area covering 95% of the fixation points. This will be measured by testing following each time interval specified.
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02729818
|Nuffield Laboratory of Ophthalmology|
|Oxford, United Kingdom, OX3 9DU|
|Principal Investigator:||Jasleen K Jolly||University of Oxford|