Visual field defects and retinal ganglion cell losses in patients with glaucoma

Objective: To determine whether the structure-function relationships for glaucoma in humans and experimental glaucoma in monkeys are similar. Methods: The study was based on retinal ganglion cell density and visual thresholds in patients with documented glaucoma. Data were analyzed with a model that predicted ganglion cell density from standard clinical perimetry, which was then compared with histologic cell counts. Results: The model, without free parameters, produced accurate and relatively precise quantification of ganglion cell density associated with visual field defects. For 437 sets of data, the unity correlation for predicted vs measured cell density had a coefficient of determinationof 0.39. The mean absolute deviation of the predicted vs measured values was 2.59 decibels (dB), and the mean ± SD of the distribution of residual errors of prediction was -0.26 ± 3.22 dB. Conclusions: Visual field defects based on standard clinical perimetry are proportional to neural losses caused by glaucoma. Clinical Relevance: The evidence for quantitative structure-function relationships provides a scientific basis for interpreting glaucomatous neuropathy from visual thresholds and supports the application of standard perimetry to establish the stage of the disease.