Correlation of Macular Ganglion Cell Complex Thickness With Frequency-doubling Technology Perimetry in Open-angle Glaucoma With Hemifield Defects

Purpose: To understand better the relationship between the macular ganglion cell complex (mGCC) thickness and visual field sensitivity assessed by frequency-doubling technology (FDT) perimetry in the standard automated perimetry (SAP) normal hemifields of glaucomatous eyes, a model of preperimetric stage of glaucoma. Patients and Methods: Thirty-four eyes of 34 patients with glaucomatous visual field defects restricted to the superior or inferior hemifield were included. Patients underwent the mGCC and circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements using spectral domain optical coherence tomography and the FDT testing with N-30 full-threshold protocol. SAP and FDT sensitivity values were averaged in the area corresponding to thickness measurements and the thickness sensitivity relationships were assessed in the SAP normal and SAP abnormal halves (Spearman's rank correlation coefficient). Results: FDT sensitivity was significantly correlated with both the cpRNFL and mGCC thicknesses either in the SAP normal (rho = 0.384 and 0.462, respectively) or in the SAP abnormal (rho = 0.402 and 0.717, respectively) halves. Correlation between the FDT sensitivity and the mGCC thickness was significantly (P = 0.016) stronger than that with the cpRNFL thickness in the SAP abnormal half. SAP sensitivity was correlated significantly (rho = 0.570) only with the mGCC thickness in the SAP abnormal half. Conclusions: Similarly strong correlations of the mGCC thickness with the FDT sensitivity in the SAP normal and SAP abnormal halves, but not with the SAP sensitivity, indicates that the mGCC thickness and the FDT sensitivity may be more optimal structure-function indicator in preperimetric stage of glaucoma.