Raman Scattering Spectroscopy to Measure Macular Pigment

This study has been completed.
Sponsor:
Information provided by:
National Institutes of Health Clinical Center (CC)
ClinicalTrials.gov Identifier:
NCT00060580
First received: May 7, 2003
Last updated: March 3, 2008
Last verified: March 2006
  Purpose

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.


Condition Intervention Phase
Raman Spectroscopy
Procedure: Raman scattering spectroscopy
Phase 1

Study Type: Interventional
Study Design: Endpoint Classification: Safety Study
Primary Purpose: Treatment
Official Title: Measurement of Macular Pigment With Resonant Raman Backscattering Spectroscopy

Resource links provided by NLM:


Further study details as provided by National Institutes of Health Clinical Center (CC):

Estimated Enrollment: 40
Study Start Date: May 2003
Estimated Study Completion Date: March 2006
Detailed Description:

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.

  Eligibility

Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

INCLUSION CRITERIA:

  1. Men and women between 18 and 75 years of age.
  2. Corrected visual acuity of 20/30 or better.
  3. Ability to understand and sign an informed consent form prior to enrollment.

EXCLUSION CRITERIA:

  1. Ocular disease, including significant explained or unexplained visual field loss.
  2. Ocular media opacities.
  3. History of epilepsy or light-triggered convulsions.
  4. A maximal pupillary dilation of less than 7 mm.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00060580

Locations
United States, Maryland
National Eye Institute (NEI)
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
  More Information

Publications:
ClinicalTrials.gov Identifier: NCT00060580     History of Changes
Other Study ID Numbers: 030156, 03-EI-0156
Study First Received: May 7, 2003
Last Updated: March 3, 2008
Health Authority: United States: Federal Government

Keywords provided by National Institutes of Health Clinical Center (CC):
Retinal Measurements
Lutein in Vivo
Raman Spectroscopy
Retinal Measurements of Lutein in Vivo in the Human Eye
Healthy Volunteer
HV

ClinicalTrials.gov processed this record on October 19, 2014