Effect of Sensitivity Disparity Between the Two Eyes on Pointwise Monocular Sensitivity Under Binocular Viewing in Patients With Glaucoma

A difference between monocular sensitivities measured with and without occlusion was observed in glaucoma. Monocular sensitivity without occlusion could have been affected differently by binocular interaction due to the sensitivity disparity between both eyes. PURPOSE: To investigate the influence of sensitivity disparity between both eyes on visual field results under binocular viewing in glaucoma. MATERIALS AND METHODS: Thirteen glaucoma patients tested by Humphrey Field Analyzer (HFA) and imo were reviewed retrospectively. On the basis of their HFA results, we defined the eye with a better HFA-MD as “the better eye” and the fellow eye with a worse HFA-MD as “the worse eye.” Depending on the pointwise pattern deviation (PD) of both eyes, all evaluated test points were classified into 4 groups: normal PD in both eyes (N/N), normal PD in the better eye but abnormal in the worse eye (N/A), abnormal PD in the better eye but normal in the worse eye (A/N), and abnormal PD in both eyes (A/A). Using imo, which can measure sensitivity with and without occluding the nontested eye, the better eye’s sensitivities with and without occlusion were compared in each group using weighted data. The weight was derived by applying the inverse probability weighting. RESULTS: Monocular sensitivity without occlusion was higher than that with occlusion in N/N (P<0.01) and the opposite was observed in A/A (P<0.05). No significant sensitivity difference between both conditions was seen in N/A or A/N. In N/A, the points showing a higher sensitivity without occlusion decreased as the sensitivity difference between both eyes increased. CONCLUSIONS: A difference between sensitivities measured with and without occlusion was observed in glaucoma. Owing to the sensitivity disparity between both eyes, monocular sensitivity without occlusion could have been affected differently by binocular interaction.