Coloured-light in Retinitis Pigmentosa. (CLIRP)

January 24, 2024 updated by: University College, London

A Pilot, Randomised, Masked Study to Investigate the Effect of Coloured-light on Colour Contrast Thresholds in Retinitis Pigmentosa.

This study will assess the effect of 2 different colours of light on colour vision in adults with retinitis pigments (RP). Participants will be 18 years or above with a genetically confirmed molecular diagnosis of RP. After informed consent, participants will have their letter chart vision and colour vision measured in their study eye. They will then be they will be randomly allocated to one of 2 groups. The study team will not know which group they have been assigned to. Group 1 will be given a coloured-light hand-held torch and be asked to apply it to their study eye for 3 minutes at home each morning between 8 - 10 am for 28 days. Group 2 will be given a different colour hand-held torch and be asked to do the same. All participants will have their letter chart vision and colour vision measured at the end of study on day 28 (+ 7 days).

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a pilot, randomised, masked, single-site trial designed to assess the effect of coloured light exposure on cone contrast thresholds (CCT) in adults with RP.

70 adults with typical RP in which the underlying genetic cause is known will be recruited from Moorfields Eye Hospital genetics service.

Following informed consent, participants will be invited for a baseline study visit.

At a baseline visit, prior to any light exposure (day 0), participants will undergo Logarithm of the Minimum Angle of Resolution (LogMAR) visual acuity (VA) and CCT measurements performed by an experienced technician according to dedicated standard operating procedures. The order of testing will be as follows:

  • Study eye: LogMAR VA
  • Study eye: CCT (Tritan and Protan)

After baseline assessments have been completed, participants will be randomised to the intervention (n=35) or control group (n=35) by a study nurse. All other study team members will be masked to group allocation.

The intervention group will be provided with a coloured torch and instructed to apply it to their study eye for 3 minutes at home each morning between 8 - 10 am for 28 days. The control group will be provided with a different coloured torch and will be instructed to follow the same protocol. The specific colours have not be disclosed here to protect masking of the study. Participants will be asked to complete a paper diary each day to record whether light was applied, the time and duration of the application and the eye to which light was applied.

The end of trial visit will be scheduled on day 28 (+7 days). Participants will undergo LogMAR VA and CCT measurements by an experienced technician according to standard operating procedures (SOP). The order of testing will be as follows:

  • Study eye: LogMAR VA
  • Study eye: CCT (Tritan and Protan)

Study Type

Interventional

Enrollment (Estimated)

70

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United Kingdom
      • London, United Kingdom
        • Moorfields Eye Hospital NHS Foundation Trust
        • Contact:
          • Hannah Dunbar, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Over 18 years old
  • Typical RP where the underlying genetic cause is known. This may include PRPF31, PRPF8, SNRNP200, RHO, RP1 [autosomal dominant] and USH2A, EYS [autosomal recessive]
  • VA of 0.30 LogMAR (6/12) or better in the study eye
  • Preserved foveal structure defined by intact outer retinal (ellipsoid zone) at the fovea on Optical Coherence Tomography (OCT) and a hyperfluorescent ring within the temporal vascular arcades on Fundus Autofluorescence (FAF) in the study eye
  • Willing and able to provide written informed consent

Exclusion Criteria:

  • Co-existing ocular pathology will be excluded; however, participants with macular oedema, a common pre-symptomatic manifestation of foveal involvement, will not be excluded
  • Concurrent and/or recent involvement in other research that is likely to interfere with the intervention within 6 months of study enrolment
  • Unwilling or able to provide written informed consent.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Coloured light 1 group
Coloured light 1 group will be provided with a coloured-light torch and instructed to apply it to their study eye for 3 minutes at home each morning between 8 - 10 am for 28 days.
Device: Coloured-light torch
Participant administered, at-home, 3-minute daily morning application (between 8 - 10am) of a coloured-light torch to the study eye.
Placebo Comparator: Coloured light 2 group
Coloured light 2 group will be provided with a different coloured-light torch and instructed to apply it to their study eye for 3 minutes at home each morning between 8 - 10 am for 28 days.
Device: Different coloured-light torch
Participant administered, at-home, 3-minute daily morning application (between 8 - 10am) of a different coloured-light torch to the study eye.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Tritan Colour Contrast Threshold (CCT)
Time Frame: Measured at Day 0 and Day 28
Tritan CCT will be measured using the ChromaTest® platform, a software program which quantifies age-corrected tritan and protan CCT using a Modified Binary Search method. Tritan CCT test endpoint is a continuous variable (units: percentage).
Measured at Day 0 and Day 28

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Protan CCT
Time Frame: Measured at Day 0 and Day 28
Protan CCT will be measured using the ChromaTest® platform, a software program which quantifies age-corrected tritan and protan CCT using a Modified Binary Search method. Protan CCT test endpoint is a continuous variable (units: percentage).
Measured at Day 0 and Day 28
LogMAR Visual Acuity (LogMAR VA)
Time Frame: Measured at Day 0 and Day 28
LogMAR VA will be measured on an electronic LogMAR acuity chart (Test Chart 2020, Thompson Software Solutions, UK), according to a forced-choice procedure.
Measured at Day 0 and Day 28
Proportion of participants losing ≥15 letters of LogMAR VA
Time Frame: Measured each day (Day 0 through Day 28)
Proportion of participants losing 15 letters of LogMAR VA or more at day 28 will be reported as a safety outcome.
Measured each day (Day 0 through Day 28)
Compliance rate
Time Frame: Measured each day (Day 0 through Day 28)
Compliance rate of application of daily, 3-minute, at-home, participant administered coloured-light exposure is a secondary endpoint. This will be collected through completion of a participant diary.
Measured each day (Day 0 through Day 28)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University College, London

Investigators

  • Principal Investigator: Hannah Dunbar, PhD, UCL Institute of Ophthalmology

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

March 1, 2024

Primary Completion (Estimated)

October 1, 2024

Study Completion (Estimated)

October 1, 2024

Study Registration Dates

First Submitted

January 12, 2024

First Submitted That Met QC Criteria

January 24, 2024

First Posted (Actual)

January 25, 2024

Study Record Updates

Last Update Posted (Actual)

January 25, 2024

Last Update Submitted That Met QC Criteria

January 24, 2024

Last Verified

January 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 161090

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Data will not be shared with other researchers

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Retinitis Pigmentosa

Clinical Trials on Coloured-light torch

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Guinea

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe