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Central nervous system (CNS) manifestations and modulation of negative dysphotopsia (ND)

Free Paper Details

First Author: S.Masket USA

Co Author(s):    Z. Rupnik   N. Fram                 

Abstract Details

Purpose:

To employ the Haag-Streit 900 visual field (VF) testing machine in Goldmann kinetic perimetry mode in order to evaluate the ND scotoma in patients with symptomatic chronic ND.

Setting:

Private practice (Advanced Vision Care) Los Angeles, CA, USA

Methods:

Employing kinetic (Goldmann) perimetry, 20 patients with chronic ND were tested under monocular occlusion with a partially opaque patch to determine the extent of the ND scotoma Patching of the contralateral eye under consistent lighting conditions produced an unexpected self-reported improvement of the ND scotoma. When repeated with fully opaque occlusion further improvement was reported. Contralateral part-time patching as therapy was attempted; while poorly tolerated, ND was improved with occlusion. Contralateral partial occlusion was then attempted with a peripherally opaque soft contact lens. This too was poorly tolerated but allowed binocular VF testing of ND. Colvard pupillometry was employed.

Results:

1 - 75% of patients noted improvement in ND with contralateral ocular occlusion 2 - ND scotoma was reduced by a mean 65% with patching of the fellow eye 3 - Scotomata from CNS, glaucoma, or retinal conditions did not change with partial to fully opaque occlusion. 4 - Under binocular VF testing the ND scotoma was markedly larger than under monocular conditions 5 - With a peripherally opaque SCL on the fellow eye the ND scotoma was markedly reduced in size and noted to be more peripherally located. 6 - Pupil size changed minimally with contralateral occlusion

Conclusions:

Reduction in the size and extent of the ND scotoma with occlusion of the fellow eye strongly suggests CNS modulation of ND. Moreover, the significantly larger ND scotoma under binocular VF testing offers an explanation as to why ND patients appear to much more symptomatic than those with VF loss associated with other conditions. At present there is not a well understood mechanism for the change in the ND scotoma with contralateral occlusion. Anecdotally, no truly monocular patients have been reported to have ND following cataract surgery. Functional MRI and EEG testing are planned to help understand CNS ND modulation.

Financial Disclosure:

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