Metabolic Mapping to Measure Retinal Metabolism
This study will test whether a new non-invasive technique can quickly and precisely measure retinal metabolism (the amount of energy retinal cells use). The retina is the part of the eye that sends information to the brain.
Participants in current NEI studies who have age-related macular degeneration (AMD), diabetic retinopathy, or von Hippel-Landau disease may be eligible for this study. Healthy volunteers will participate as controls. Patients with AMD must be 60 years of age or older; those with VHL disease or diabetic retinopathy must be 18 or older.
Participants undergo the tests and procedures required in the NEI study in which they previously enrolled. In addition, for the current study, they undergo metabolic mapping. For this procedure, the subject's eyes are dilated, and different amounts of low-level light are shone into the eye to see how different cells respond with changes in metabolism. Measurements are taken while the subject breathes room air and while he or she breathes medical grade oxygen for about 1 minute. The entire procedure takes about 15 minutes.
Procedure: Feasibility Study - Imaging System
|Study Design:||Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Diagnostic
|Official Title:||A Novel Non-Invasive In Vivo Imaging System to Measure Retinal Metabolism|
- Fluorescence anisotropy
- The difference in fluorescence anisotropy values within subjects under room air and 100% oxygen exposure (one minute exposure time).
|Study Start Date:||September 2006|
|Study Completion Date:||September 2010|
|Primary Completion Date:||June 2008 (Final data collection date for primary outcome measure)|
Background. Alterations in retinal metabolism are associated with blinding conditions and vision loss. We propose to apply a non-invasive in vivo retinal imaging system to investigate key physiologic processes affecting retinal metabolism. The imaging system is designed to quantify and characterize the topology of retinal metabolism in 3-dimensional space across 40--130 picosecond time periods and allows dynamic measurement of physiologically relevant events.
Objectives. The primary objectives of our study are to: (1) evaluate the utility of this system in a clinical setting; and (2) examine variation in retinal metabolism within retinal cell subtypes under environmental conditions optimized to support this metabolism. The working hypothesis of our first objective is that the imaging system will be easily and efficiently implemented in a clinical setting and will yield stable and repeatable results. The working hypothesis for our second objective is that people with or at high risk for progression to sight threatening retinal disease will exhibit different metabolic profiles than an age- and sex-matched disease-free comparison group. Their peers with less severe disease may exhibit differences with severe diseased and non-diseased groups. The long-term goal of the project is to address the following research questions: Are metabolic profiles generated by the imaging system effective for determining presence and severity of retinal diseases?; and if so, are these metabolic profiles useful in identifying people at risk for progression to sight threatening forms of retinal diseases?
Study Population. We will first apply the systems in 3 groups of 10 people exhibiting a range of severity in retinal diseases that influence retinal metabolism; these diseases are: age-related macular degeneration (AMD); diabetic retinopathy (DR); and von-Hippel-Lindau (VHL) disease.
Design. Cross-sectional sampling design. If the system yields accurate, stable, and repeatable results it will be applied in longitudinal studies to evaluate prognostic utility for estimating the risk of progression to sight-threatening AMD, DR, or VHL disease.
Outcome Measures. The magnitude and 3-D topographic profile of fluorescence anisotropy values across physiologically meaningful time periods for a 20 degree field centered on the macula. Fluorescence anisotropy of our system provides a measure of retinal metabolism.
Please refer to this study by its ClinicalTrials.gov identifier: NCT00385333
|United States, Maryland|
|National Institutes of Health Clinical Center, 9000 Rockville Pike|
|Bethesda, Maryland, United States, 20892|