Evaluation of Cirrus HD-OCT Ganglion Cell Complex, Retinal Nerve Fiber Layer, and Neuroretinal Rim Area Measurements for Detecting Open Angle Glaucoma

Abstract

 

Purpose:

 

To compare the accuracies of the Cirrus HD-OCT (Carl Zeiss Meditec, Inc.) optic nerve head (ONH) topography, ganglion cell complex (GCC), and retinal nerve fiber layer (RNFL) measurements to discriminate glaucomatous from healthy eyes.

 

Methods:

 

Two hundred and thirty eight eyes with open angle glaucoma and one hundred and thirty four healthy eyes were included in the study. Subjects were recruited from the longitudinal Diagnostic Innovations in Glaucoma Study (DIGS) and from the African Descent and Glaucoma Evaluation Study (ADAGES). All patients underwent imaging with the Cirrus HD-OCT. Optic nerve head and macular scans were done within six months of each other. Healthy eyes had an IOP less than or equal to 21 mmHg with no history of increased IOP, or evidence of repeatable visual field damage. Eyes were considered glaucomatous if 3 of their last 4 visual field test results were abnormal. Neuroretinal rim area (NRA) and parapapillary RNFL thickness measurements were obtained from the ONH scan while GCC measurements were obtained from the macular scan. Diagnostic accuracy was evaluated by the area under the receiver operating characteristic curve (AUC).

 

Results:

 

The parameter with the largest AUC for RNFL measurements was the inferior quadrant (0.89 ± 0.02) while the largest AUC for the GCC measurements was the average thickness (0.86 ± 0.02). ONH topographical measurements showed NRA to have the largest AUC (0.82 ± 0.02). The AUC for NRA measurements was significantly lower than that of inferior RNFL thickness measurements (0.82 vs. 0.89 p=.0028); however, NRA and average GCC thickness measurements were not statistically different (0.82 vs 0.86 p=.16). When comparing average GCC thickness measurements and inferior ONH RNFL thickness no statistical difference was found (0.86 vs. 0.89 p=0.09).

 

Conclusions:

 

RNFL measurements performed significantly better than rim area for detection of glaucoma. For GCC measurements, no statistically significant differences were detected when compared to RNFL or rim area.

 

Clinical Trial:

 

http://www.clinicaltrials.gov NCT00221897

 

Keywords: ganglion cells • optic nerve • imaging/image analysis: clinical