Abstract
Purpose: :
To study changes of retinal ganglion cell complex (GCC) and analyze morphofunctional correlations in patients with glaucoma.
Methods: :
Study included 96 patients: 22 (36 eyes) with ocular hypertension (OHT), 59 (102) eyes with open-angle glaucoma (OAG), and 15 (22 eyes) healthy control subjects. All patients and control subjects were evaluated by visual acuity measurements, slit-lamp biomicroscopy, gonioscopy, intraocular pressure (IOP) measurements, stereoscopic fundus examination, automated perimetry (Humphrey Visual Field Analyzer II 750, Carl Zeiss Meditec, Jena, Germany), and Fourier-domain OCT (RTVue-100, Optovue, Fremont, CA) imaging using optic nerve head (ONH) and GCC mapping protocols. Peripapillary retinal nerve fiber layer thicknesses (RFNL) and retinal ganglion cell complex (GCC) thicknesses were measured. The following GCC parameters were measured: Mean thickness of GCC, global loss volume of GCC (GLV%) and focal loss volume of GCC (FLV%).
Results: :
Mean value of the visual field index (VFI) in control and OHT groups, in early, moderate and severe glaucoma was -0.04±1.05dB, -0.4±1.45 dB, -1.9±2.97 dB, -7.21±1.92 dB, and -13.78±2.69 dB, respectively. In OHT group, Mean GCC thickness, FLV, and GLV were 96.1 µm (p>0.05), 1,5% (p≤0.05), and 4,8% (p>0.05), respectively. In all glaucoma groups, the GCC parameters were significantly lower than in the control group (p≤0.05). RNFL was significantly reduced only in glaucoma group (p <0.05). Statistically significant correlation was found in moderate and severe glaucoma groups between a) VFI and FLV (r=0.69, p<0.001; r=0.65, p<0.001, respectively); b) VFI and GLV (r=0.58, p<0.001; r=0.61, p<0.001, respectively). Inverse correlation between VFI and RNFL was found in moderate glaucoma group (r=-0.72, p<0.00001).
Conclusions: :
Our results indicate that 1) there is early macular damage in early stages of glaucoma, and 2) FLV is highly sensitive GCC parameter for the diagnosis of preperimetric stage glaucoma.
Keywords: ganglion cells • nerve fiber layer • visual fields