Comparison of the Pattern of Retinal Ganglion Cell Damage Between Patients With Compressive and Glaucomatous Optic Neuropathies

PURPOSE. To compare the patterns of retinal ganglion cell (RGC) damage in the macular and peripapillary areas in compressive optic neuropathy (CON) and glaucomatous optic neuropathy (GON) using spectral-domain optical coherence tomography (SD-OCT), and to determine the usefulness of SD-OCT macular and peripapillary analysis in discriminating between CON and GON. METHODS. Sixty-three eyes with CON, 68 eyes with GON, and 73 healthy control eyes were included. Spectral-domain OCT scanning of the circumpapillary and macular area was performed to measure the global and six-sector thicknesses of the circumpapillary retinal nerve fiber layer (cpRNFL), and the macular retinal nerve fiber layer (mRNFL) and macular ganglion cell layer (mGCL) thicknesses in the nine macular subfields as defined by the Early Treatment Diabetic Retinopathy Study (ETDRS). RESULTS. Compared to the healthy eyes, the mRNFL was significantly thinner in six ETDRS subfields (inner and outer subfields of superior, nasal, and inferior areas) in CON, but in only two subfields (outer-inferior and outer-temporal subfields) in GON. The mGCL was thinner in all nine subfields in CON, but in only four subfields (inner and outer subfields of inferior and temporal areas) in GON. The temporal cpRNFL was significantly thinner in CON but was not involved in GON. The macular parameters performed better than cpRNFL parameters in discriminating between the CON and GON. CONCLUSIONS. Distinct differences in the patterns of RGC damage in the macular and peripapillary areas were found between CON and GON. Evaluation of the macular RGC damage may be a useful adjunct for distinguishing CON from GON when optic disc and visual field examinations are inconclusive.