Evaluation of optic disc in open-angle glaucoma with hemifield defect by Heidelberg retinal tomography

Objective To investigate whether the glaucomatous optic disc change demonstrated by Heidelberg retinal tomography (HRT) is consistent to the distribution of the visual field defects and whether Heidelberg retinal tomography, (HRT) parameters in primary open angle glaucoma (POAG) and normal tension glaucoma (NTG) are different. Method Sixty-four eyes of 64 patients with open angle glaucoma (27 of POAG, 37 of NTG) and hemifield abnormality detected by Humphery Field Analyzer (HFA) were tested by HRT. The HRT parameters and the visual field results were divided into two parts (0°-180° and 180°-360°) for the corresponding analysis. Results Comparing with the half disc corresponding to the intact hemifield, the half disc corresponding to the defective hemifield has significantly higher values of cup/disc area ratio and cup shape measure, but has significantly lower values of rim area, the thickness and cross-section area of the retinal nerve fiber layer. No significant differences were found between NTG and POAG eyes in the HRT parameters of the half disc corresponding to the defective hemifield. Conclusions The optic disc changes detected by HRT are consistent to the distribution of the visual field defects, cup/disc area ratio, cup shape measure, rim area, mean thickness and cross-section area of the retinal nerve fiber layer, and they are the relatively sensitive parameters. That the HRT parameters of NTG and POAG are similar suggests they possibly have certain similar mechanisms in the development of glaucomatous neuropathy.