Photoreceptor Sensitivity ThresholdsNCT02674425
Wearable Dark-adaptometer in Normal Adult Healthy Volunteers
An observational study of Photoreceptor Sensitivity Thresholds, run by University of Liverpool at 1 site in United Kingdom.
Trial summary
Conventional dark-adaptometers are unsuitable as a mass screening tool due to their high cost, lack of easy portability, need of trained staff and a totally dark room to be operated, arbitrary testing procedures, associated time waste in clinic and patient burden to mention a few. Read more about this study
- Who is it for?
- Ages 18 to 70 yearsHealthy volunteers can take part
- Conditions the study is for
- Photoreceptor Sensitivity Thresholds
- What is being tested?
- Dark Adaptometer
- Type of treatment
- Medical device
- How many people
- 20 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- Sep 2016to Jul 2018
- Phase
- Observational
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Healthy adult volunteers with no prior/current eye problems or family history of genetic eye diseases and good general health.
Who may be able to join
- Refractive error: ≤ ±5 dioptres spherical (myopia/hyperopia) equivalent; ≤ 3 dioptres cylinder (astigmatism) equivalent.
Who cannot join
- Subjects not in age range and/or unable to fully understand the informed consent and/or unable to comply with study procedures.
- Self-reported history of depression, lack of sleep, psychiatric disorders, or neurological diseases such as Alzheimer's and Parkinson's disease.
- Self-reported history of diabetes, stroke, or multiple sclerosis.
- Self-reported hypovitaminosis A, alcoholism, liver or intestinal disease, malabsorption, protein calorie malnutrition, or sickle cell anaemia.
- Use of psychoactive drugs (including lithium salts for mood stabilisation).
- Use of dietary intake of ascorbic acid, vitamin A, B, E or other antioxidant supplements in the last two weeks.
- Recurrent practice of activities that expose the retina to ultra-violet radiation such as sailing, fishing, sunbathing or tanning saloons.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
University of Liverpool
Liverpool, Merseyside, L78TX
About this study
Official title: Evaluation of a Novel Wearable Light-emitting System for Measuring Dark-adaptation Thresholds in Normal Adult Healthy Volunteers
Conventional dark-adaptometers are unsuitable as a mass screening tool due to their high cost, lack of easy portability, need of trained staff and a totally dark room to be operated, arbitrary testing procedures, associated time waste in clinic and patient burden to mention a few. Consequently, dark adaptometers are not routinely used as clinical tools for retinal diagnosis and monitoring despite the inherent benefits over other visual electrophysiology equipment such as the ERG system, whose cost and features may often be surplus to optometrists' requirements.
This trial will assess the dark-adaptometry testing performance of a novel light-emitting system by generating full dark-adaptation threshold functions in normal adult healthy volunteers.
Read more
The novel system has been proposed to overcome the issues associated with current instrumentation; it is semi-automatic and easy to use without the need of any skilled operator.
It is envisaged that this system could spread the practice of dark-adaptometry testing and its adoption by high-street optometrists. This will allow diagnosing a number of retinal pathologies more quickly and more reliably that, faced with an ageing population, represents a major asset to the Health Community and the NHS.
This trial will involve 20 healthy volunteers, distributed in equal number in 2 groups of 18-40 and 50-70 years old, respectively. Proven the good health and eye condition of the participants, one of their eyes will be randomly-allocated and undergo dark-adaptometry testing 3 times on separate days within 3 weeks.
Testing will clarify whether by using the novel system it is possible to reproduce state-of-the-art threshold measurements as good or better than those produced by commercially-available dark-adaptometers. Threshold measurements in the elderly will be compared with literature data adjusted to exclude aged crystalline lens and pupillary miosis contributions. Data variability and system usability will be also assessed.
Read the detailed description
All details elsewhere in the documentation
- Conditions
- Photoreceptor Sensitivity Thresholds
- Being tested
- Dark Adaptometer
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dark AdaptometerDevice
| Study group | Role | What they receive |
|---|---|---|
| Young adults (18-40) | Healthy adult volunteers, aged between 18 and 40, with no prior/current eye problems or family history of genetic eye diseases and good general health. Receives: Device: Dark Adaptometer | |
| Older adults (50-70) | Healthy adult volunteers, aged between 50 and 70, with no prior/current eye problems or family history of genetic eye diseases and good general health. Receives: Device: Dark Adaptometer |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time to Rod-cone Break (RCB)
RCB (time) values were determined by recording the time required for the participant to observe a light stimulus of a particular luminosity.
Participants viewed the light stimuli without their optical correction. These consisted of a white (λpeak = 464 nm; chromaticity coordinates - 2° observer: x = 0.269, y = 0.324) circular test target of 0.255 mm radius, forming a visual angle of around 33°. Participants were asked to press a response button on the handheld joystick when the test target was visible and had 750 ms to make a response after target onset. Target intensity started at approximately 4.865 cd*m-2. Light stimuli were presented approximately every 2.6 s for a duration of 150 ms each. If the subject under test did not respond to the stimuli, the target intensity remained at the same initial level of approximately 4.865 cd*m-2 until the subject responded. If the subject reported perception of the light stimulus within the response window, the luminance was reduced by 0
Measured: 40 minutes
Absolute Threshold
Rod sensitivity (absolute threshold luminance) values measured in cd*m-2
Measured: 40 minutes
Absolute Threshold Time
Time taken to reach absolution threshold measured in minutes
Measured: 40 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Feb 2016 (estimated)
- Study startSep 2016
- Primary completionMay 2018
- Study completionJul 2018
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Photoreceptor Sensitivity ThresholdsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case only
- Time perspective
- Other
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Liverpool
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Rachel L Williams, PhD, Principal investigator, University of Liverpool
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02674425
- Sponsor's protocol ID
- UoL001185
- Status last verified
- Jun 2024
- First submitted
- 27 Jan 2016
- Last updated
- 1 Jul 2024
- Results posted
- Yes, on ClinicalTrials.gov
Study at a glance
From the registry record, last updated by the sponsor on 1 Jul 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of a Novel Wearable Light-emitting System for Measuring Dark-adaptation Thresholds in Normal Adult Healthy Volunteers
- ClinicalTrials.gov ID
- NCT02674425
- Acronym / sponsor ID
- UoL001185
- Conditions
- Photoreceptor Sensitivity Thresholds
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- University of LiverpoolUniversity, hospital or other
- Study start
- Sep 2016
- Primary completion
- May 2018 (actual)
- Study completion
- Jul 2018 (actual)
- First posted
- 4 Feb 2016 (estimated)
- Results
- Posted 1 Jul 2024
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Conventional dark-adaptometers are unsuitable as a mass screening tool due to their high cost, lack of easy portability, need of trained staff and a totally dark room to be operated, arbitrary testing procedures, associated time waste in clinic and patient burden to mention a few. Consequently, dark adaptometers are not routinely used as clinical tools for retinal diagnosis and monitoring despite the inherent benefits over other visual electrophysiology equipment such as the ERG system, whose cost and features may often be surplus to optometrists' requirements.
This trial will assess the dark-adaptometry testing performance of a novel light-emitting system by generating full dark-adaptation threshold functions in normal adult healthy volunteers.
The novel system has been proposed to overcome the issues associated with current instrumentation; it is semi-automatic and easy to use without the need of any skilled operator.
It is envisaged that this system could spread the practice of dark-adaptometry testing and its adoption by high-street optometrists. This will allow diagnosing a number of retinal pathologies more quickly and more reliably that, faced with an ageing population, represents a major asset to the Health Community and the NHS.
This trial will involve 20 healthy volunteers, distributed in equal number in 2 groups of 18-40 and 50-70 years old, respectively. Proven the good health and eye condition of the participants, one of their eyes will be randomly-allocated and undergo dark-adaptometry testing 3 times on separate days within 3 weeks.
Testing will clarify whether by using the novel system it is possible to reproduce state-of-the-art threshold measurements as good or better than those produced by commercially-available dark-adaptometers. Threshold measurements in the elderly will be compared with literature data adjusted to exclude aged crystalline lens and pupillary miosis contributions. Data variability and system usability will be also assessed.
Detailed description
All details elsewhere in the documentation
Study design
- Observational model
- Case only
- Time perspective
- Other
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Young adults (18-40) | – | Device: Dark AdaptometerHealthy adult volunteers, aged between 18 and 40, with no prior/current eye problems or family history of genetic eye diseases and good general health. |
| Older adults (50-70) | – | Device: Dark AdaptometerHealthy adult volunteers, aged between 50 and 70, with no prior/current eye problems or family history of genetic eye diseases and good general health. |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Healthy adult volunteers with no prior/current eye problems or family history of genetic eye diseases and good general health.
Key inclusion criteria (1 listed)
- Refractive error: ≤ ±5 dioptres spherical (myopia/hyperopia) equivalent; ≤ 3 dioptres cylinder (astigmatism) equivalent.
Key exclusion criteria (7 listed)
- Subjects not in age range and/or unable to fully understand the informed consent and/or unable to comply with study procedures.
- Self-reported history of depression, lack of sleep, psychiatric disorders, or neurological diseases such as Alzheimer's and Parkinson's disease.
- Self-reported history of diabetes, stroke, or multiple sclerosis.
- Self-reported hypovitaminosis A, alcoholism, liver or intestinal disease, malabsorption, protein calorie malnutrition, or sickle cell anaemia.
- Use of psychoactive drugs (including lithium salts for mood stabilisation).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Dark Adaptometer | Device | Older adults (50-70), Young adults (18-40) |
Primary outcome
Time to Rod-cone Break (RCB)
Time frame: 40 minutes
RCB (time) values were determined by recording the time required for the participant to observe a light stimulus of a particular luminosity. Participants viewed the light stimuli without their optical correction. These consisted of a white (λpeak = 464 nm; chromaticity coordinates - 2° observer: x = 0.269, y = 0.324) circular test target of 0.255 mm radius, forming a visual angle of around 33°. Participants were asked to press a response button on the handheld joystick when the test target was visible and had 750 ms to make a response after target onset. Target intensity started at approximately 4.865 cd*m-2. Light stimuli were presented approximately every 2.6 s for a duration of 150 ms each. If the subject under test did not respond to the stimuli, the target intensity remained at the same initial level of approximately 4.865 cd*m-2 until the subject responded. If the subject reported perception of the light stimulus within the response window, the luminance was reduced by 0
Absolute Threshold
Time frame: 40 minutes
Rod sensitivity (absolute threshold luminance) values measured in cd*m-2
Absolute Threshold Time
Time frame: 40 minutes
Time taken to reach absolution threshold measured in minutes
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Jul 2024.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Rachel L Williams, PhD principal investigator
University of Liverpool
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Photoreceptor Sensitivity Thresholds, run by University of Liverpool at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 1 Jul 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 1 Jul 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time to Rod-cone Break (RCB) (time frame: 40 minutes). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Jul 2024.