Application of available technology and objective indexes are very important for the early diagnosis, monitoring and therapeutic evaluation of primary open angle glaucoma(POAG). Many studies have determined retinal damage in structure and function in POAG.However, the study on the association of structural damage and functional abnormality in early POAG is still lack.

This study was to evaluate the relationship between structural and functional changes of retina in early stage of POAG.

A prospectively pilot study was performed under the approval of Ethic Committee of Shenzhen Eye Hospital from January 2011 to June 2013.Based on Helsinki Declaration, written informed consent was obtained from subject prior to entering the cohort.Ninety-five eyes of 95 POAG patients were included as the study group, and 41 eyes of 41 non-glaucoma subjects were enrolled at the same period as controls.The structural parameters of retinas were measured using RTVue-100 OCT and Cirrus HD-OCT respectively, including macular ganglion cell complex (GCC)-Avg thickness and peripapillary retinal neural fibril layer (RNFL)-Avg thickness; and the functional parameters of retinas were obtained by Humphrey visual filed analyzer and RETI scan 3.15 system respectively, including MD of visual field and PhNR of flash electroretinogram(F-ERG). The associations between the GCC or RNFL thickness and MD or amplitude of PhNR were evaluated by linear and curvilinear regression models.

The MD, GCC-Avg, RNFL-Avg and PhNR amplitude were (-0.68±1.72)dB, (97.17± 4.82)μm, (102.51±8.74)μm and (49.61±11.01)μV respectively in the control subjects, and those in the POAG patients were (-10.82±9.87)dB, (75.07±12.29)μm, (69.09±12.96)μm and (28.38±11.52)μV, showing significant differences between them (t=6.549, 11.118, -15.061, 9.956, all at P=0.001). The curvilinear regression model appeared to better describe the relationship between GCC thickness and MD (R²=0.595, F=97.089, P<0.001); while a linear regression model seemed to be better fit for the relationship between GCC thickness and amplitude of PhNR (R²=0.437, F=103.413, P<0.001). RNFL thickness analysis showed the similar regression models with MD and amplitude of PhNR as GCC thickness, but R² values were higher between the RNFL thickness and MD (R²=0.606, F=101.666, P<0.001) or amplitude of PhNR (R²=0.454, F=54.983, P<0.001).

Both GCC thickness and RNFL thickness show a curvilinear relationship with MD and a linear relationship with amplitude of PhNR.Goodness-of-fit of RNFL thickness is superior to GCC thickness.

Glaucoma/primary, open angle; Retinal ganglion cell; Retinal nerve fiber; Electroretinogram; Visual field; Computerized tomography