Assessment of neuroretinal function in a group of functional amblyopes with documented LGN deficits

Brown, Brian, Feigl, Beatrix, Gole, Glen A., Mullen, Kathy T., & Hess, Robert F. (2013) Assessment of neuroretinal function in a group of functional amblyopes with documented LGN deficits. Ophthalmic and Physiological Optics, 33(2), pp. 138-149.

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Abstract

Purpose In this study we examine neuroretinal function in five amblyopes, who had been shown in previous functional MRI (fMRI) studies to have compromised function of the lateral geniculate nucleus (LGN), to determine if the fMRI deficit in amblyopia may have its origin at the retinal level.

Methods We used slow flash multifocal ERG (mfERG) and compared averaged five ring responses of the amblyopic and fellow eyes across a 35 deg field. Central responses were also assessed over a field which was about 6.3 deg in diameter. We measured central retinal thickness using optical coherence tomography. Central fields were measured using the MP1-Microperimeter which also assesses ocular fixation during perimetry. MfERG data were compared with fMRI results from a previous study.

Results Amblyopic eyes had reduced response density amplitudes (first major negative to first positive (N1-P1) responses) for the central and paracentral retina (up to 18 deg diameter) but not for the mid-periphery (from 18 to 35 deg). Retinal thickness was within normal limits for all eyes, and not different between amblyopic and fellow eyes. Fixation was maintained within the central 4° more than 80% of the time by four of the five participants; fixation assessed using bivariate contour ellipse areas (BCEA) gave rankings similar to those of the MP-1 system. There was no significant relationship between BCEA and mfERG response for either amblyopic or fellow eye. There was no significant relationship between the central mfERG eye response difference and the selective blood oxygen level dependent (BOLD) LGN eye response difference previously seen in these participants.

Conclusions Retinal responses in amblyopes can be reduced within the central field without an obvious anatomical basis. Additionally, this retinal deficit may not be the reason why the LGN BOLD (blood oxygen level dependent) responses are reduced for amblyopic eye stimulation.

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ID Code: 58315
Item Type: Journal Article
Refereed: Yes
Keywords: amblyopia, multifocal electroretinogram, lateral geniculated nucleus, functional MRI, optical coherence tomography, fixation stability
DOI: 10.1111/opo.12024
ISSN: 1475-1313
Subjects: Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300) > Ophthalmology (111301)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300) > Vision Science (111303)
Divisions: Current > Schools > School of Biomedical Sciences
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Current > Schools > School of Optometry & Vision Science
Copyright Owner: Copyright 2013 The College of Optometrists
Copyright Statement: The definitive version is available at www3.interscience.wiley.com
Deposited On: 18 Mar 2013 22:17
Last Modified: 05 Mar 2014 11:03

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