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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
Sponsor:
Information provided by (Responsible Party):
University of Oxford

Study Description
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Brief Summary:

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
Retina; Change

Study Design
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Study Type : Observational
Actual Enrollment : 40 participants
Observational Model: Other
Time Perspective: Prospective
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
Groups and Cohorts
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Outcome Measures
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Primary Outcome Measures :
  1. 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.


Secondary Outcome Measures :
  1. 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.


Eligibility Criteria
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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Forty healthy adult volunteers (over 18) will be recruited from the University of Oxford. They will need to have healthy eyes and good eyesight (better than 6/7.5 Snellen visual acuity), with no eye diseases apart from refractive error (needing to wear glasses or contact lenses). Participants will need to be able to sit upright at the microperimeter (which involves putting their chin on a chin rest and being able to sit still for up to 20 minutes at a time), and be able to press a button to indicate when they have seen a light stimulus.
Criteria

Inclusion Criteria:

  • Participant is willing and able to give informed consent for participation in the study.
  • Male or female.
  • Age 18 - 60 years.
  • Best corrected visual acuity of at least Logmar 0.1 in right eye.
  • Able to tolerate physical requirements of microperimetry testing i.e. able to sit still at the microperimeter in dark environment and indicate when a light stimulus has been seen using the provided button.

Exclusion Criteria:

  • Any co-existing ocular pathology, either pre-existing or identified on initial ocular examination, not including refractive error or previous cataract surgery
Contacts and Locations
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Information from the National Library of Medicine

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


Locations
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United Kingdom
Nuffield Laboratory of Ophthalmology
Oxford, United Kingdom, OX3 9DU
Sponsors and Collaborators
University of Oxford
Investigators
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Principal Investigator: Jasleen K Jolly University of Oxford
More Information
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Additional Information:

Publications of Results:

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Responsible Party: University of Oxford
ClinicalTrials.gov Identifier: NCT02729818    
Other Study ID Numbers: DarkAdapt
First Posted: April 6, 2016    Key Record Dates
Last Update Posted: November 8, 2018
Last Verified: October 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided
Keywords provided by University of Oxford:
Retina
Microperimetry
Visual Fields