Early Detection of Retinal Nerve Fiber Layer (RNFL) Injury Using Polarimetry

Abstract

Abstract: : Purpose:To assess the RNFL in glaucomatous eyes with achromatic field defects limited to one hemifield. Methods:Eyes with glaucomatous optic neuropathy and abnormal achromatic automated perimetry (AAP) limited to one hemifield consistent with glaucoma were enrolled in this multicenter study. Eligible fields had a glaucoma hemifield test (GHT) outside normal limits associated with a cluster of 3 contiguous abnormal points (at least 1 point at the p<0.5% level) and no points at the p<0.5% level in the "normal" hemifield. Eyes with any other ocular abnormality or unreliable visual field were excluded. Polarimetry was performed using a variable corneal compensator (GDx–VCC^TM, Laser Diagnostic Technologies, Inc., San Diego, CA). GDx–VCC data were considered abnormal when a TSNIT (RNFL map) parameter was at the p<2% significance level or if the deviation map showed at least 3 contiguous points at the p<0.5% significance level. The GDx–VCC normative database was used to determine abnormality. Results:26 eyes (26 OAG patients) were included. Mean pattern standard deviation was 8.29 ± 5.05 dB. A corresponding GDx–VCC RNFL defect was associated with 22/26 (84.6%) abnormal hemifields and in 13/26 (50%) regions associated with normal achromatic hemifields. Conclusion: In OAG, GDx–VCC RNFL injury often involves the superior and inferior optic nerve even when achromatic field defects are limited to one hemifield.

Keywords: nerve fiber layer • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • visual fields