Correlation Between Retinal Nerve Fiber Layer and Optic Neuropathy Measured by Optical Coherence Tomography in Primary Open Angle Glaucoma

Objective: To comparatively evaluate the retinal nerve fiber layer(RNFL) thickness and optic nerve head(ONH) by optical coherence tomography(OCT) in early,advanced and late stages of primary open angle glaucoma(POAG),and to study the correlation between the RNFL thickness and glaucomatous optic neuropathy.Methods: Forty cases(60 eyes) with POAG were examined by OCT with circular scans around ONH(diameter=3.46 mm) to observe the RNFL,with radiate scans around ONH to evaluate the rim area,and cup/disc area ratio(C/D AR).RNFL thickness,rim area,and C/D AR were compared among the early,advanced and late POAG groups.Correlation and regression analysis was used to show the correlation between RNFL thickness and glaucomatous optic neuropathy(rim area and C/D AR) in all cases.Results: There were significant difference in RNFL average thickness among the three groups.There was a significant positive correlation between RNFL average thickness and rim area(r=0.719,P0.01),and a negative correlation between RNFL average thickness and C/D AR(r=-0.712,P0.01).Conclusion: OCT can quantitatively measure the RNFL thickness and show the difference of RNFL thickness among the early,advanced and late stages of POAG.The RNFL thickness gradually decreases while C/D AR increases,but rim area reduced during the deteriorating process of POAG,and rim area has more impact on the RNFL thickness than C/D AR does.