Abstract
Purpose: :
To collect normative data for the thicknesses of the macular retinal nerve fiber layer (mRNFL) and the compound of macular retinal ganglion cell layer and inner plexifor layer (mRGIPL) and to compare a group of glaucoma patients to age-matched healthy volunteers. The research was carried out to test the diagnostic value of a segmentation tool for macular high-resolution optical coherence tomography (HR-OCT).
Methods: :
120 normal volunteers and 60 glaucoma patients are scanned with Cirrus (TM) HR-OCT of the macular area. Additionally all subjects received a thorough ophthalmologic examination including best corrected visual acuity, slit-lamp examination, binocular ophthalmoscopy of optic disc and macula, visual field tests (HFA 30-2, HFA 10-2), scanning laser opthalmoscopy (HRT3) and scanning laser polarimetry (GDx). The main analysis was based on a segmentation algorithm for macular HR-OCT. This tool provides global (8 deg radius) and focal thickness values of the mRNFL and the mRGIPL. These two layers were compared between the healthy volunteers and the glaucoma patients using t-tests.
Results: :
Glaucoma patients showed a highly significant reduction in mRNFL and mRGIPL compared to age-matched volunteers (-36.1% and -21.7%; p<0.001) in a preliminary analysis. In glaucoma patients the topographic patterns of mRGIPL reduction matched well with those of mRNFL reduction and also with the topography of HFA 10-2 visual field tests.
Conclusions: :
Analyses of the macular RNFL and the mRGIPL promise potential for glaucoma diagnosis. Since both measure the same neural cells at different locations in the retina concordant results of both may considerably increase the confidence in examination results.
Keywords: imaging/image analysis: clinical • nerve fiber layer • macula/fovea