Macular DegenerationNCT02090751
Development of a Device to Measure Dark Adaptation
An observational study of Macular Degeneration and Age-Related Macular Degeneration, run by University of Manchester at 1 site in United Kingdom.
Trial summary
Age Related Macular Disease (AMD) is easily the leading cause of blindness in older people in developed countries. It affects between 30 and 50 million individuals worldwide, with around 30% of the over 65's showing early signs of the disease. Read more about this study
- Who is it for?
- Ages 50 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Macular Degeneration, Age-Related Macular Degeneration
- How many people
- 40 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- Jul 2014to Apr 2015
- Phase
- Observational
- Are there results?
- None posted in the registry
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 50 to 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Participants will be recruited from a the greater manchester area by a call for volunteers, through the local newspaper, a university email list and through the Hale Barns Macular Disease Association
Who may be able to join
- They understand their rights as a research Participant and are willing and able to sign a Statement of Informed Consent.
- They are over 50 years and less than 80 years of age.
- They are willing and able to perform the experimental task required.
- They are not a current participant in other studies. Lifestyle factors
- Diet that includes animal and/or vegetable fats. Health factors
- Good ocular health, the following will be admitted Pseudophakia, aphakic with good VA (better than 6/12), AMD with AREDS category 1,2,or 3.
- Good systemic health, the following may be admitted Hypertension Thyroid disease Arthritis Depression
- Medication, that is not hepatotoxic or retinotoxic directly or by treating a disease that is may be admitted. Use British National Formulary (BNF) to check if unsure.
Who cannot join
- Unlikely to be available, willing, and able to attend
- Unable to give consent.
- Current participant in other studies.
- Subject to any condition that may adversely affect fat intake (proxy for Vit A) or retinal function.
- Lifestyle factors
- Diet that excludes animal and/or vegetable fats.
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- Health factors
- Ocular Any active disease, e.g. · Glaucoma, Cataract if VA worse than 6/12 · Diabetic Retinopathy · Retinal detachment · Uveitis Treatments · Laser Sx. to cornea, capsule or retina · Recent cataract extraction within 12 weeks · Drops
- Systemic Diabetes Liver disease, Hepatitis: Past or present Digestive disorders, e.g. Crohns, irritable bowel syndrome (IBS), lactose intolerance Bowel surgery, stomach staple, ileostomy, colostomy Kidney disorder (elevated iron) Chronic alcoholism or drug abuse
- Medication, hepatotoxic or retinotoxic directly or by treating a disease that is. If unsure use BNF and seek advice of ophthalmologist/study leader. Examples include:
- Interferon alpha
- Vitamin A derivatives (Chronic eczema)
- Amiodarone (Heart disease)
- Chloroquine/Hydrochloroquine (Plaquenil) (Rheumatoid Arthritis/ Malaria)
- Tamoxifen (Breast Cancer)
- Chlorpromazine (Schizophrenia)
- Deferoxamine (Thalassemia, blood transfusions/ kidney disease)
- Phenothiazines (Anti-psychotic/epilepsy)
- Ethambutol (TB)
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
University of Manchester
Manchester, Greater Manchester, M13 9PL
About this study
Official title: A Study to Evaluate the Sensitivity and Specificity of a Device to Measure Dark Adaptation in Subjects With and Without Early Macular Disease
Age Related Macular Disease (AMD) is easily the leading cause of blindness in older people in developed countries. It affects between 30 and 50 million individuals worldwide, with around 30% of the over 65's showing early signs of the disease. Severe AMD has a devastating impact on the quality of life; it causes extensive visual impairment, making reading difficult and driving impossible. Patients lose their independence and become a major burden on public health systems.
Present treatment options are limited. Many new therapies are under development and all will need evaluation using a test with high specificity and sensitivity for early AMD. The present application will develop such an instrument. The prototype was funded by a previous i4i FS (feasibility study ll-FS-0110-14036). The new device measures sensitivity to a dim flickering light using the same principle as an established european conformity marked (CE marked) instrument. The original method involved lights of different wavelengths and higher intensities.
The instrument in this study assesses night vision, which is selectively damaged in early stage AMD. In low lighting, the investigators vision depends on specialized rod photoreceptors. Cone photoreceptors, which provide daytime vision, remain normal in the early stages of the disease. By the time patients complain of reduced (cone-based) visual acuity, they will have had the disease for many years and lost many thousands of photoreceptors.
Read the detailed description
In a clinical environment dark adaptation (DA) is measured by exposing the patient to a brief bright light and then measuring their sensitivity to a flickering light. This sensitivity recovery has a typical appearance; an early rapid recovery mediated by the colour vision system (cone photoreceptors) and a slower recovery of the low light system (rod photoreceptors).
If the measurements are made against a black background then a bi exponential model is suitable, however if a dim luminous background is used then the recovery is better modelled by a exponential bi linear model. We will use the exponential bilinear model, which has seven parameters. The parameters are as follows; the exponential cone phase is modelled by the cone threshold, cone coefficient, and cone time constant. The S2 rod phase is modelled by its commencement time. This is the time when the rod system becomes more sensitive than the cone system, sometimes called the cone-rod break point (alpha) and the slope of the subsequent thresholds. The late rod phase (S3) is similarly modelled by a transition time or rod-rod breakpoint (beta) and its slope.
If the initial bright light is sufficiently intense then the recovery of the rod phase (S2) is termed rate limited. There is evidence that this recovery rate is a useful measure of the health of the light sensing layer of the eye an adjoining tissues, the retina, retinal pigment epithelium and choroid. It is these tissues that are thought to be affected in age related macular disease.
In this study we will measure rate of rod recovery sometimes called the S2 phase. We want to see whether this measurement can be used to identify patients with and without early macular disease.
- Keywords
- Retinal Rod Photoreceptor Cells, Dark Adaptation
- Medical subject headings
- Macular Degeneration
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| No Maculopathy | Aged 50 to 80 with no macular disease | |
| Early Maculopathy | Aged 50 to 80 with early AREDS defined 2,3 age related maculopathy |
What is being measured
The primary outcome is the main question the study is designed to answer.
The rate of recovery of the rod phase S2
Dark adaptation will be measured in 40 participants; 20 healthy and 20 with early macular disease. This index of retinal health will be analysed for its sensitivity and specificity for the identification participants with macular disease.
Measured: At participant visit only
Secondary outcomes (2)
Lifestyle questionnaire
We have a simple questionnaire to investigate factors reported in the literature to have an effect on macular health. We will use the categorical data collected by the questionnaire to assess the influence of these lifestyle measures on the index of retinal health found from the dark adaptation measurement.
Measured: At participant visit only.
Participant Experience Questionnaire
We will give each participant a questionnaire when they finish their visit and will ask for their experience of the process of dark adaptation measurement.
Measured: Within one month of participant visit.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Mar 2014 (estimated)
- Study startJul 2014
- Primary completionFeb 2015
- Study completionApr 2015
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Macular DegenerationStudies 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-control
- Time perspective
- Cross-sectional
- Enrolment
- 40 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Manchester
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Dr Jeremiah Kelly, University of Manchester
- Investigators
- Ian J Murray, PhD, Principal investigator, University of Manchester
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02090751
- Sponsor's protocol ID
- II-LB-0712-20001
- Status last verified
- Jul 2016
- First submitted
- 12 Mar 2014
- Last updated
- 6 Jul 2016
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Jul 2016. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Study to Evaluate the Sensitivity and Specificity of a Device to Measure Dark Adaptation in Subjects With and Without Early Macular Disease
- ClinicalTrials.gov ID
- NCT02090751
- Acronym / sponsor ID
- II-LB-0712-20001
- Keywords
- Retinal Rod Photoreceptor Cells, Dark Adaptation
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 40 participants (actual)
- Lead sponsor
- University of ManchesterUniversity, hospital or other
- Study start
- Jul 2014
- Primary completion
- Feb 2015 (actual)
- Study completion
- Apr 2015 (actual)
- First posted
- 18 Mar 2014 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Age Related Macular Disease (AMD) is easily the leading cause of blindness in older people in developed countries. It affects between 30 and 50 million individuals worldwide, with around 30% of the over 65's showing early signs of the disease. Severe AMD has a devastating impact on the quality of life; it causes extensive visual impairment, making reading difficult and driving impossible. Patients lose their independence and become a major burden on public health systems.
Present treatment options are limited. Many new therapies are under development and all will need evaluation using a test with high specificity and sensitivity for early AMD. The present application will develop such an instrument. The prototype was funded by a previous i4i FS (feasibility study ll-FS-0110-14036). The new device measures sensitivity to a dim flickering light using the same principle as an established european conformity marked (CE marked) instrument. The original method involved lights of different wavelengths and higher intensities.
The instrument in this study assesses night vision, which is selectively damaged in early stage AMD. In low lighting, the investigators vision depends on specialized rod photoreceptors. Cone photoreceptors, which provide daytime vision, remain normal in the early stages of the disease. By the time patients complain of reduced (cone-based) visual acuity, they will have had the disease for many years and lost many thousands of photoreceptors.
Detailed description
In a clinical environment dark adaptation (DA) is measured by exposing the patient to a brief bright light and then measuring their sensitivity to a flickering light. This sensitivity recovery has a typical appearance; an early rapid recovery mediated by the colour vision system (cone photoreceptors) and a slower recovery of the low light system (rod photoreceptors).
If the measurements are made against a black background then a bi exponential model is suitable, however if a dim luminous background is used then the recovery is better modelled by a exponential bi linear model. We will use the exponential bilinear model, which has seven parameters. The parameters are as follows; the exponential cone phase is modelled by the cone threshold, cone coefficient, and cone time constant. The S2 rod phase is modelled by its commencement time. This is the time when the rod system becomes more sensitive than the cone system, sometimes called the cone-rod break point (alpha) and the slope of the subsequent thresholds. The late rod phase (S3) is similarly modelled by a transition time or rod-rod breakpoint (beta) and its slope.
If the initial bright light is sufficiently intense then the recovery of the rod phase (S2) is termed rate limited. There is evidence that this recovery rate is a useful measure of the health of the light sensing layer of the eye an adjoining tissues, the retina, retinal pigment epithelium and choroid. It is these tissues that are thought to be affected in age related macular disease.
In this study we will measure rate of rod recovery sometimes called the S2 phase. We want to see whether this measurement can be used to identify patients with and without early macular disease.
Study design
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| No Maculopathy | – | –Aged 50 to 80 with no macular disease |
| Early Maculopathy | – | –Aged 50 to 80 with early AREDS defined 2,3 age related maculopathy |
Who may qualify
- Ages
- 50 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Participants will be recruited from a the greater manchester area by a call for volunteers, through the local newspaper, a university email list and through the Hale Barns Macular Disease Association
Key inclusion criteria (8 listed)
- They understand their rights as a research Participant and are willing and able to sign a Statement of Informed Consent.
- They are over 50 years and less than 80 years of age.
- They are willing and able to perform the experimental task required.
- They are not a current participant in other studies. Lifestyle factors
- Diet that includes animal and/or vegetable fats. Health factors
Key exclusion criteria (19 listed)
- Unlikely to be available, willing, and able to attend
- Unable to give consent.
- Current participant in other studies.
- Subject to any condition that may adversely affect fat intake (proxy for Vit A) or retinal function.
- Lifestyle factors
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
The rate of recovery of the rod phase S2
Time frame: At participant visit only
Dark adaptation will be measured in 40 participants; 20 healthy and 20 with early macular disease. This index of retinal health will be analysed for its sensitivity and specificity for the identification participants with macular disease.
2 secondary outcomes
Lifestyle questionnaire
Time frame: At participant visit only.
Participant Experience Questionnaire
Time frame: Within one month of participant visit.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Jul 2016.
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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.
Ian J Murray, PhD principal investigator
University of Manchester
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 Macular Degeneration and Age-Related Macular Degeneration, run by University of Manchester 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 8 inclusion and 19 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 6 Jul 2016. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
The rate of recovery of the rod phase S2 (time frame: At participant visit only). 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 6 Jul 2016.