Luminance-modulated adaptation of global flash mfERG: Fellow eye losses in asymmetric glaucoma

Patrick H W Chu, Ho Lung Henry Chan, Brian Brown

Research output: Journal article publicationJournal articleAcademic researchpeer-review

21 Citations (Scopus)

Abstract

PURPOSE. To use the global flash multifocal electroretinogram (mfERG) in patients with asymmetric glaucoma to determine whether retinal function is affected in fellow eyes that have no glaucomatous visual field defects. METHODS. Forty normal subjects and 12 patients with asymmetric glaucoma were recruited for visual field and mfERG measurement. The mfERG was assessed by using a global-flash stimulation paradigm with four video frames: 103 scaled hexagonal elements followed by a dark frame, a global-flash frame, and a dark frame. The localized luminance difference was set at 96%, 65%, 49%, and 29% display contrast during the four different test conditions, respectively. The first-order kernel response was measured, and the "adaptive index" which has been used previously was calculated. RESULTS. In fellow eyes with normal visual fields, the amplitude of the induced component (IC) was significantly reduced, and the adaptive index was reduced by a factor of almost 10 (P < 0.0001), as it was in the glaucomatous eyes. Although the adaptive index in the better (fellow) eye of the patients with glaucoma was slightly higher than in the eyes with diagnosed glaucoma, these differences were not statistically significant. CONCLUSIONS. The significant reduction of the adaptive index in the better eyes in subjects with asymmetric glaucoma shows that the fast adaptive mechanism(s) were reduced in these eyes. This implies that eyes that have functionally normal visual acuity and visual fields have abnormal fast-adaptive mechanisms.
Original languageEnglish
Pages (from-to)2626-2633
Number of pages8
JournalInvestigative Ophthalmology and Visual Science
Volume48
Issue number6
DOIs
Publication statusPublished - 1 Jun 2007

ASJC Scopus subject areas

  • Ophthalmology

Cite this