RNFL and Ganglion Cell Complex Thickness in Normal Hemifield According to the Severity of Glaucoma

ABSTRACT

PURPOSE: To analyze the thickness of the circumpapillary retinal nerve fiber layer (cRNFL) and macular ganglion cell complex (mGCC) in apparently normal hemifield areas of glaucomatous eyes with superior or inferior visual hemifield defects according to their severity compared with the same hemifield of normal eyes using Topcon 3D spectral-domain optical coherence tomography (SD-OCT). METHODS: The present study included 90 normal eyes and 90 glaucomatous eyes with superior or inferior visual hemifield defects that underwent cRNFL and mGCC imaging using 3D SD-OCT. The cRNFL and mGCC parameters were compared between normal hemifield in glaucomatous eyes and the same hemifield in normal eyes. The mean deviation (MD) parameters (Mild MD > -6 dB, 54 eyes; Moderate -6 dB ≥ MD ≥ -12 dB, 60 eyes; Severe MD < -12 dB, 30 eyes) in glaucomatous eyes were also compared between the 3 severity groups. RESULTS: The average hemifield cRNFL thickness was 93.6 ± 24.2 µm and 118.1 ± 14.1 µm in superior normal hemifield of glaucomatous eyes and controls, respectively, and 107.8 ± 19.1 µm and 124.9 ± 17.1 µm in inferior normal hemifield of glaucomatous eyes and controls, respectively. mGCC thickness was 95.8 ± 5.9 µm and 103.5 ± 7.7 µm in superior normal hemifield of glaucomatous eyes and controls, respectively, and 93.4 ± 8.2 µm and 104.5 ± 8.2 µm in inferior normal hemifield of glaucomatous eyes and controls, respectively (all p < 0.05). The thickness parameters were decreased in normal hemifield of glaucomatous eyes, which significantly decreased according to the severity (MD) of visual field defect (all p < 0.01). CONCLUSIONS: The measurement of cRNFL and mGCC thickness in normal hemifield of glaucomatous eyes using SD-OCT is useful in detecting structural glaucomatous changes before visual field defects appear.