Color Vision as a Measure for Inherited Retinal Diseases


Background: – The purpose of this study is to find out whether color vision measured with the Cambridge Color Test is a good way to examine the severity of inherited retinal diseases (IRDs). IRDs are a major cause of vision loss worldwide, but very little is known about how the diseases affect color vision over time. This study will tell us if color vision may be used to track changes in inherited retinal diseases over time. Objectives: – To improve understanding of color vision as a way to measure changes in inherited retinal diseases. Eligibility: – People 5 years of age or older who have an IRD. – Healthy volunteers at least 5 years of age. Design: – Participants will make at least one visit to the National Eye Institute clinic. If they sign up for more tests, they may have up to three visits to the NEI clinic. – Participants will be asked questions about their medical and eye history. – Participants will be given an eye exam, including eye drops to dilate their pupils. They will take the Cambridge Color Test, which includes looking at a monitor and pressing a button, and arranging colored circles. Several other tests may be offered, but participants can decline to take them. – Treatment will not be provided as part of this study.

Full Title of Study: “Color Vision as an Outcome Measure for Clinical Trials of Inherited Retinal Degenerations”

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Prospective
  • Study Primary Completion Date: April 14, 2017

Detailed Description

Objective: The aims of this study are to 1) examine the sensitivity of the Cambridge Color Test (CCT) and the low vision CCT (LvCCT) to the severity of retinal disease in inherited retinal degeneration (IRD) by comparing color vision status with changes in photoreceptor structure and function, 2) examine the effects of eccentric fixation and reduction in visual acuity on color discrimination thresholds obtained with the CCT and LvCCT, and 3) establish normal ranges for the CCT and the LvCCT and determine the intra-session and inter-session variabilities for these tests. Study Population: Up to 59 healthy volunteers and 144 IRD participants age 5 or older will be enrolled in this study. Design: This study will be comprised of three related projects. For Aim 1, color discrimination thresholds (CCT and LvCCT) and assessments of retinal structure (imaging) and function (perimetry/microperimetry and electroretinogram) will be measured in 144 IRD participants with varying retinal phenotypes and visual acuities. IRD participants will be divided into four major categories: 1) cone & cone-rod dystrophies, 2) rod-cone dystrophies, 3) inherited maculopathies, and 4) inherited retinal dysfunction syndromes. The fourth category will be used for IRDs that do not match the description for categories 1-3 (i.e., x-linked retinoschisis, congenital stationary night blindness). Degree of severity of retinal dysfunction in IRD participants will be determined relative to the normal ranges obtained from the healthy volunteers (see Aim 3a below). For Aim 2 color discrimination thresholds (CCT and LvCCT) will be measured in one eye from 12 healthy volunteers in order to examine the effects of eccentric fixation and reduced visual acuity on color thresholds independent of retinal pathology. Between one and three study visits will be required for this aim. Aim 3 will be comprised of two parts. For Aim 3a, color thresholds will be collected from both eyes (for intraocular variability) of 35 healthy volunteers age 5 or older. For Aim 3B, color discrimination thresholds (CCT and LvCCT) will measured from 12 healthy volunteers twice in one session and then again at a second visit occurring within two months of the initial visit to determine intra-session and inter-session variability. Outcome Measures: For both the CCT and LvCCT, an overall quantitative measure of color vision will be obtained from the calculation of achromatic area. The sensitivity of CCT and LvCCT will be examined by comparing achromatic area for IRD participants with varying levels of phenotype severity defined by measures of retinal structure and function. Secondary outcomes for this study include: 1) evaluation of sensitivity of the CCT and LvCCT to disease severity, 2) evaluation of the effects of decreased visual acuity and eccentricity on color discrimination thresholds (CCT and LvCCT), 3) establishment of the normal range of color discrimination thresholds (CCT and LvCCT) as a function of age, and 4) determination of intra- and inter-session variabilities of the two tests.

Clinical Trial Outcome Measures

Primary Measures

  • For both the CCT and LvCCT, a quantitative measure of color vision will be obtained from the calculation of achromatic area.
    • Time Frame: Ongoing

Secondary Measures

  • Determination of variabilities of the two tests
    • Time Frame: Ongoing
  • Establishment of the normal range of color discrimination thresholds
    • Time Frame: Ongoing
  • Evaluation of effects of disease on color discrimination thresholds
    • Time Frame: Ongoing
  • Evaluation of sensitivity of the CCT and LVCCT
    • Time Frame: Ongoing

Participating in This Clinical Trial

Inclusion Criteria

1. Participants must be 5 years of age or older. 2. Participant (or legal guardian) must understand and sign the protocol s informed consent document. 3. Participant must be able to cooperate with the testing required for this study. 4. Participant s eyes must have clarity of ocular media and degree of pupil dilation sufficient to permit adequate fundus photography. 5. For IRD Participants only: 1. Participant must have IRD, defined as evidence of retinal rod- and cone-mediated dysfunction and degeneration established by standard clinical methods including field tests, ERG, and imaging. 2. Participant must have a measurable visual acuity. 6. For Healthy Volunteers only: 1. Participant must have visual acuity of 20/20 or better. EXCLUSION CRITERIA:

1. Participant is taking medications known to alter color vision, such as hydroxychloroquine (Plaquenil ), sildenafil (Viagra ), ethambutol, chloroquine amiodarone, and pamidronate disodium. 2. Participant has another ocular disease that may confound the study results, such as diabetic retinopathy, vascular occlusions, retinopathy related to drug toxicity, optic neuropathy, or central serous chorioretinopathy.

Gender Eligibility: All

Minimum Age: 5 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • National Eye Institute (NEI)
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Brett G Jeffrey, Ph.D., Principal Investigator, National Eye Institute (NEI)


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