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

Brown, Brian, Feigl, Beatrix, Gole, Glen A., Mullen, Kathy and Hess, Robert F. (2013) Assessment of neuroretinal function in a group of functional amblyopes with documented LGN deficits. Ophthalmic and Physiological Optics, 33 2: 138-149. doi:10.1111/opo.12024

Author Brown, Brian
Feigl, Beatrix
Gole, Glen A.
Mullen, Kathy
Hess, Robert F.
Title Assessment of neuroretinal function in a group of functional amblyopes with documented LGN deficits
Journal name Ophthalmic and Physiological Optics   Check publisher's open access policy
ISSN 0275-5408
Publication date 2013-03
Year available 2013
Sub-type Article (original research)
DOI 10.1111/opo.12024
Volume 33
Issue 2
Start page 138
End page 149
Total pages 12
Place of publication Chichester, West Sussex, United Kingdom
Publisher Wiley-Blackwell
Collection year 2014
Language eng
Formatted 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.
Keyword Amblyopia
Multifocal electroretinogram
Lateral geniculate nucleus
Functional MRI
Optical coherence tomography
Fixation stability
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Medicine Publications
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