Abstract:
Current methods for discriminating cataractous lenses from healthy lenses
during preclinical studies are based on either histopathological or clinical
assessments which are weakened by subjectivity. In this work, four optical
spectroscopic techniques: slit lamp microscopy, multispectral imaging (MSI),
Laser-induced autofluorescence (LIAF) and attenuated total reflectance Fourier
transform infrared (ATR-FTIR) spectroscopy have been used to study and
characterize cataractous as well as healthy lenses of Sprague Dawley rats. With
the aid of slit lamp images, mean integrated optical density (IOD) of cataractous
lenses were found to increase with severity. Analysis of multispectral images
captured in transmission and reflection and scattering modes showed that five
wavelengths markers discriminates cataractous lenses from healthy lenses with
470 nm and 625 nm in reflection mode, and 435 nm, 590 nm and 700 nm in
transmission mode. The scattering spectral bands could not discriminate
cataractous lenses from healthy lenses. Fisher‟s linear discriminant analysis
showed more than 85 % success in classifying the lenses. LIAF results revealed
that spectra peak wavelengths of cataractous lenses were red-shifted with
cataractous lens tissues exhibiting high autofluorescence intensity than the
healthy ones. Infrared spectra from cataractous lens tissues showed intensity
difference and some wavenumber shifts in vibrational modes associated with
proteins from the healthy ones. P-values obtained from independence T-test
showed significant differences in absorbed intensities at 7 peak wavenumbers.
Upon applying Hierarchical cluster analysis, the infrared lens spectra data were
classified as cataractous or healthy. These optical techniques may be potentially
applied for improved cataract diagnosis.
