Detection of macular and circumpapillary structural loss in normal hemifield areas of glaucomatous eyes with localized visual field defects using spectral-domain optical coherence tomography.

BACKGROUND: To investigate thickness of the macular ganglion cell complex (mGCC) and circumpapillary retinal nerve fiber layer (cRNFL) in retinal segments without visual field (VF) loss in glaucomatous eyes in which localized VF defects were confined to a single hemifield, using spectral-domain optical coherence tomography (SD-OCT).
METHODS: Seventy-one Asian glaucomatous patients and 64 normal subjects underwent mGCC and cRNFL imaging employing RTVue-100 SD-OCT. We compared both thickness parameters in retinal segments without VF defects with those in segments in which such defects were evident, and in matched segments of normal controls. Linear regression analysis was used to investigate the relationship between mGCC and cRNFL thickness parameters of segments with or without VF defects, and glaucoma status based on Humphrey field analyzer (HFA) indices.
RESULTS: Mean mGCC thickness in the hemiretinae of glaucomatous eyes without VF defects was 87.2 ± 9.3 μm, significantly lower than in matched control hemiretinae (96.2 ± 5.0 μm; p < 0.001), but significantly higher than in glaucomatous hemiretinae with VF defects (76.4 ± 9.9 μm; p < 0.001). A similar trend was also noted with mean cRNFL thickness. There were significant associations between both thickness parameters in glaucomatous hemiretinae with or without VF loss and degree of VF damage at initial presentation.
CONCLUSIONS: Perimetrically normal hemifields of glaucomatous eyes had significantly lower mGCC and cRNFL thicknesses than did the corresponding retinal regions of healthy eyes. SD-OCT may be a useful ancillary diagnostic tool for evaluation of early macular and circumpapillary structural changes in glaucomatous eyes with localized VF defects.