Difference in correspondence between visual field defect and inner macular layer thickness measured using three types of spectral-domain OCT instruments.
OBJECTIVE
To compare the relationship between visual field sensitivity (VFS) and macular parameters measured using three spectral-domain optical coherence tomography (SD-OCT) instruments and to determine a base level (=floor effect) for macular parameters.


METHODS
We imaged 127 glaucomatous eyes (1 eye per subject) using three different OCT instruments, i.e., the Cirrus, RTVue and 3D OCT devices; 76 normal eyes were evaluated as controls using the same instruments. The thicknesses of the macular retinal nerve fiber layer (mRNFL), ganglion cell layer+inner plexiform layer (GCL/IPL), and mRNFL+GCL/IPL (GCC) were analyzed. The VFS of the area analyzed by OCT was expressed in decibels and the 1/Lambert scale. For each parameter, the structure-function relationship and the base level were evaluated by regression analysis. The strength of the correlations between the instruments was compared by the bootstrapping method.


RESULTS
All of the macular parameters evaluated exhibited statistically significant correlations with VFS. The average GCC measured by all three SD-OCT instruments and the average mRNFL thickness measured by the Cirrus and 3D OCT instruments had similar correlations with VFS. The average GCL/IPL thickness measured by the Cirrus OCT instrument was better correlated with VFS that was measured by the 3D OCT instrument (p = 0.031). The base level GCC thickness measured by all three instruments was approximately 65% of that of normal eyes. The base level mRNFL thickness measured with the Cirrus and OCT instruments was 52 and 48%, respectively, of that of normal eyes. The base level GCL/IPL thickness measured with the Cirrus and 3D instruments was 71 and 75%, respectively, of that of normal eyes.


CONCLUSIONS
The three SD-OCT instruments evaluated showed similar structure-function relationships in terms of GCC and mRNFL measurements. The base levels of the macular parameters determined by the three instruments differed, due, at least partly, to the scanning area defined by each instrument.
Division of Ophthalmology, Department of Surgery, Graduate School of Medicine, Kobe University, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
Kaori
K
Ueda
Akiyasu
A
Kanamori
Azusa
A
Akashi
Yuki
Y
Kawaka
Yuko
Y
Yamada
Makoto
M
Nakamura
D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000295:instrumentation*; D014786:Vision Disorders / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*