RETINAL NERVE FIBER LAYER REFLECTANCE MECHANISMS

Project: Research project

Description

The diagnosis and management of glaucoma and other disorders of the optic
nerve require sensitive methods for detecting and measuring damage to the
retinal nerve fibers. Measurement of visual sensitivity with static
perimetry and ophthalmoscopic assessment of the condition of the optic disc
are currently used in clinical practice, but newer methods for assessing
the nerve fiber layer of the retina directly are being developed. All such
methods depend on the interaction of the nerve fiber layer with the light
used to observe it, but there is little quantitative data describing this
interaction. Furthermore, the mechanisms by which light and the nerve
fibers interact are unknown. The long-term objective of the research
proposed in this application is to provide a comprehensive quantitative
description of the optical properties of the nerve fiber layer of the
retina, and to establish the anatomical basis for its reflectance.
AChieving this objective will provide a solid foundation upon which all
methods for assessing the nerve fiber layer can be developed, and the
knowledge gained may lead to totally new approaches. The specific aims of this project are to 1) test the hypothesis that the
major component of NFL reflectance (wavelengths shorter than 560 nm) arises
from light scattered by thin, cylindrical organelles (perhaps microtubules)
of nerve axons and that reflectance at long wavelengths (>560 nm) results
from a second mechanism and 2) test the hypothesis that nerve fiber layer
reflectance is proportional to nerve fiber layer thickness. Nerve fiber layer reflectance will be measured in vivo by directional
imaging reflectometry and in vitro by imaging microreflectometry to
determine if short-wavelength reflected light exhibits the optical
properties expected of reflections from this cylinders and to see if a
second spectral component can be revealed by various manipulations.
Reflectometrically studied areas of nerve fiber layer will then undergo
morphometric analyses by light and electron microscopy to determine the
amount of nerve fiber tissue present and to quantify the cellular
organelles (microtubules, neurofilaments, and cell membranes) in the nerve
axons.
StatusFinished
Effective start/end date8/1/906/30/09

Funding

  • National Institutes of Health: $329,200.00

Fingerprint

nerve fibers
reflectance
birefringence
glaucoma
damage
axons
optical properties
polarimetry
cells
bundles
slabs
light scattering
tomography
physical properties

ASJC

  • Medicine(all)