Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia, Australia.
Ophthalmic Physiol Opt. 2013 Mar;33(2):138-49. doi: 10.1111/opo.12024. Epub 2013 Jan 12.
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.
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.
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.
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.
在这项研究中，我们检查了五名弱视患者的神经视网膜功能，先前的功能磁共振成像 (fMRI) 研究表明他们的外侧膝状体 (LGN) 功能受损，以确定弱视的 fMRI 缺陷是否起源于视网膜水平。
我们使用慢闪烁多焦点 ERG (mfERG)，并比较了 35 度视野中弱视眼和对侧眼的平均五个环响应。还评估了直径约为 6.3 度的中央视野的响应。我们使用光学相干断层扫描测量中央视网膜厚度。中央视野使用 MP1-Microperimeter 进行测量，该仪器还在进行视野检查时评估眼固视。mfERG 数据与先前研究的 fMRI 结果进行比较。
弱视眼的中央和旁中央视网膜（最大直径达 18 度）的反应密度振幅（从第一个主要负向到第一个正向（N1-P1）的反应）降低，但中周边（从 18 度到 35 度）则没有。所有眼睛的视网膜厚度均在正常范围内，且在弱视眼和对侧眼之间没有差异。五名参与者中有四名在超过 80%的时间内将注视点保持在中央 4°内；使用双变量轮廓椭圆面积 (BCEA) 评估的注视点与 MP-1 系统的评分相似。对于弱视眼或对侧眼，BCEA 与 mfERG 反应之间均无显著关系。在这些参与者中，先前观察到的中央 mfERG 眼反应差异与选择性血氧水平依赖 (BOLD) LGN 眼反应差异之间无显著关系。
在中央视野内，弱视患者的视网膜反应可能会降低，而没有明显的解剖学基础。此外，这种视网膜缺陷可能不是弱视眼刺激时 LGN BOLD（血氧水平依赖）反应降低的原因。
