Abstract
Abstract: :
Purpose:To investigate differences in the NFL characterized by Fourier analysis of polarimetry data between normal-tension glaucoma and POAG patients. Methods:Fourier analysis was applied to the NFL thickness estimates as measured by scanning laser polarimetry (GDx) from a group of normal-tension glaucoma (NTG) patients and two matched groups of POAG patients, one matched for mean defect (MD) and one matched for CPSD. Comparisons between groups were made for all GDx output parameters as well as for all Fourier coefficients and for a linear discriminant function (LDF) based on the Fourier coefficients (reported ARVO 2001). We also compared glaucoma detection rates for these groups (comparing the use of the GDx number and the Fourier LDF) and the association between all measures and visual field indices. Results:Significant differences were found between the NTG group and the POAG groups for two Fourier coefficients (amplitude of the third and fifth harmonic), but no other measure. The GDx number correctly detected 40% of the NTG group while the Fourier LDF correctly detected 80%. An equal number of Fourier coefficients and GDx parameters significantly correlated with visual field indices for both POAG groups, however for the NTG group only Fourier measures were significantly correlated. Conclusion:Fourier analysis of the NFL can reveal differences in the structure of the NFL between NTG and POAG, and can be used to more accurately detect NTG than the GDx number. The strong association between the Fourier measures and visual field indices for the NTG group suggests this type of NFL representation is very sensitive to retinal functional integrity.
Keywords: 430 imaging/image analysis: clinical • 484 nerve fiber layer • 432 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)