Frequency doubling technology perimetry in non-arteritic ischaemic optic neuropathy with altitudinal defects

Abstract

Aim: To determine if frequency doubling technology perimetry (FDT) is more sensitive to optic nerve injury in non-arteritic ischaemic optic neuropathy (NAION) than standard automated perimetry (SAP). Methods: Charts from 18 patients (20 eyes) with NAION with altitudinal defects who underwent a complete neuro-ophthalmic examination, SAP, and FDT were reviewed. The extent of damage as determined by SAP, FDT, and clinical estimation of the regional extent of optic disc pallor was compared. 10 subjects (20 eyes) with normal ocular examinations and full appearing optic nerve heads were included as a control group. Results: FDT demonstrated more extensive visual field defects in the relatively intact hemifield on SAP (proportion of locations at 5% or worse in the total deviation plot was 8.7% (SD 6.2%) for SAP and 38.3% (39.5%) for FDT pConclusion: FDT appears more sensitive to axonal injury reflected by the extent of optic disc pallor in altitudinal NAION than SAP and in some patients reveals visual dysfunction in the hemifield that appeared relatively uninvolved when evaluated using SAP.