Raman Spectroscopy Clinical Trial
Official title:
Measurement of Macular Pigment With Resonant Raman Backscattering Spectroscopy
This study will evaluate the ease and reliability of Raman scattering spectroscopy, a new
technique to measure the amount of the pigment lutein in the retina, the light-sensitive
tissue lining the back of the eye. The highest concentrations of lutein are in the center of
the retina, called the macula, which is the area most important for fine, detailed vision.
The functions of lutein are not fully known. Besides absorbing blue light, it may help
protect against abnormal changes in the retina, such as age-related macular degeneration.
Until recently, lutein was measured using long, cumbersome, and difficult tests. This study
will evaluate a new instrument that provides faster measurements. It will be tested under
different conditions, such as wearing or not wearing glasses or contact lenses, or dilating
or not dilating the pupil of the eye.
Healthy normal volunteers between 20 and 65 years of age may be eligible for this study,
which involves two visits to the NIH Clinical Center, as follows:
Visit 1 - Screening
- Medical history and physical examination, including measurement of vital signs (blood
pressure, pulse, temperature, and breathing rate), and examination of the head and
neck, heart and lungs, and arms and legs.
- Eye examination, including eye chart test, eye pressure measurement, examination of
pupils and eye movements, and examination of the retina (back part of the eye) using a
strong light and magnifying lens after dilation of the pupils.
- Raman scattering spectroscopy to measure lutein. For this test, the subject looks with
one eye at a brief, bright flash of bluish light (similar to a flashbulb light) from a
laser. This is repeated several times. Subjects who wear glasses or contact lenses for
distance vision will be tested without them and then again with a lens in front of the
eye. Subjects who do not wear glasses or contact lenses will be tested before and after
dilation of the pupil.
- Contrast sensitivity to assess ability to identify an object from the background and to
see everyday objects. The subject looks at and identifies a variety of objects of
different shapes and sizes.
- Color vision to determine the ability to identify different shades of color. The
subject arranges a line of colorful discs, similar to checkers, in order of similar
shades.
Visit 2 - Repeat Spectroscopy
Subjects return 1 week after the screening visit for a repeat Raman scattering spectroscopy
to evaluate the precision of the measurements.
The primary objective of this study is to evaluate the degree of variability in retinal measurements of lutein, a carotenoid macular pigment of human retina in normal volunteers, with a new and novel technique of resonant Raman scattering spectroscopy. This technique is generally more objective than psychophysical techniques used for lutein measurements, such as heterochromatic flicker photometry. Raman scattering spectroscopy is non-invasive and the levels of ocular exposure to argon laser light used in this technique are well below the safety limits recommended by the American National Standards Institute. ;
Endpoint Classification: Safety Study, Primary Purpose: Treatment
| Status | Clinical Trial | Phase | |
|---|---|---|---|
| Completed |
NCT03146715 -
The Effect of a Nutrient Dense Food on the Skin CarotenoidLevels of School Age Children
|
N/A |