In a binocular visual field (VF) study of negative dysphotopsia (ND), the scotoma and symptoms were markedly reduced by partial or full contralateral ocular occlusion, suggesting that the central nervous system plays a role in ND, although the mechanism for this finding is uncertain, according to a study presented at AAO 2020 Virtual.
Negative dysphotopsia occurs in 15% to 20% of patients but no device, or “dysphotometer,” exists to measure the complaints; therefore, only patient-reported outcomes are used. The researchers analyzed the peripheral VF in patients with ND using Goldmann kinetic VF testing. Under the study, 23 patients with ND had VF testing under monocular contralateral occlusion with a partially opaque patch to measure the ND scotoma, or non-seeing area within the VF. Patients said that contralateral occlusion produced an improvement in ND symptoms. When testing was repeated with fully opaque occlusion, further improvement in symptoms was reported and documented. Binocular VF testing also was performed with partial contralateral occlusion using a peripherally opaque custom soft contact lens.
Results showed 78% of patients (20 cases) reported a mean 65% reduction of ND symptoms with contralateral occlusion. Under binocular VF testing, the ND scotoma was markedly larger than with partial occlusion of the fellow eye. However, these findings were not demonstrated with VF loss due to glaucoma or retinal detachment.
Reference
Masket S, et al. Central nervous system manifestations and modulation of negative dysphotopsia. Presented at: AAO 2020 Virtual [Session: PO007-20.]
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