Glaucoma Diagnosis by Mapping Peripapillary Nerve Fiber Layer Thickness With Fourier Domain Optical Coherence Tomography

Abstract

 

Purpose:

 

To evaluate the glaucoma diagnostic performance of peripapillary nerve fiber layer (ppNFL) thickness mapping using high-speed, high-resolution Fourier-domain optical coherence tomography (FD-OCT).

 

Methods:

 

Participants in the Advanced Imaging for Glaucoma (www.AIGStudy.net) were scanned using the RTVue FD-OCT system (Optovue, Inc. Fremont, CA), which performs 26,000 axial scans per second and has 5-micron depth resolution. We developed a 4-mm diameter Nerve Head Map (NHM4) scan pattern which includes 12 radial scans and 6 circular scans with diameters from 2.5 to 4 mm. We developed an automated image processing algorithm to detect the NFL boundary and map the ppNFL thickness in an annular region of 2.5-4.0 mm diameter. The results were compared with ppNFL measurements obtained from a conventional time-domain OCT system (Stratus, Carl Zeiss Meditec, Inc.) using the 3.4 mm diameter circular scan in the same eyes.

 

Results:

 

OCT scans were obtained from 113 normal (N), 74 pre-perimetric glaucoma (PPG), and 108 perimetric glaucoma (PG) eyes. The diagnostic power was assess by the area under the receiver operating curve (AROC) and the reproducibility was assessed by coefficient of variance (CV) in the Table 1. FD-OCT showed a trend toward better diagnostic accuracy and reproducibility.Table 1. Diagnostic accuracy and reproducibility of overall ppNFL thickness average  

 

Conclusions:

 

ppNFL measurement by FD-OCT provided a moderate improvement in diagnostic accuracy and reproducibility over TD-OCT. This is expected based on the sampling of more retinal locations in a shorter period of time, in addition to greater resolution.

 

Keywords: imaging/image analysis: clinical • optic nerve • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)