Ozawa Kenji, Takahashi Shunsuke, Mochizuki Kiyofumi, Miyake Yozo
Department of Ophthalmology, Gifu University Graduate School of Medicine, 1-1, Yanagido, Gifu-shi, Gifu, 501-1194, Japan.
Kobe Eye Center, Next Vision, 2-1 Minatojima, Minamimachi Chuo-ku, Kobe, 650-0047, Japan.
Doc Ophthalmol. 2019 Dec;139(3):247-256. doi: 10.1007/s10633-019-09711-9. Epub 2019 Aug 2.
To report the findings in two patients with unilateral cone-rod dysfunction with the a-wave larger than the b-wave, i.e., negative-type, full-field electroretinogram (ERG).
Standard ophthalmological examinations were performed including the medical history, measurements of the best-corrected visual acuity and intraocular pressures, slit-lamp biomicroscopy, ophthalmoscopy, spectral-domain optical coherence tomography, fundus autofluorescence, fluorescein angiography, and perimetry. ERG examinations were carried out with the ISCEV standard. Immunoblot analysis using the patient's sera was performed to determine the presence of the recoverin1 antibody.
The common findings in these two patients were: unilateral, male sex, sudden onset of photophobia or a reduction in the vision at an advanced age, preserved visual acuity, no complaint of night blindness, normal fundus appearance, negative-type dark-adapted 3.0 ERGs with reduced a-wave amplitudes, absent light-adapted 3.0 ERGs, and very reduced but recordable dark-adapted 0.01 ERGs. In addition, the multifocal ERGs in all areas except that in a hexagonal area within a 2.5° radius of the fovea were very reduced. Patients with similar findings have been reported earlier, but the subnormal a-wave of the dark-adapted 3.0 ERGs and extensive morphological alterations of the retina in the posterior pole in the OCT images were different from those of the reported patients. The OCT images showed an indistinct interdigitation zone and discontinuous ellipsoid zone. Anti-recoverin antibodies were not detected.
Negative ERGs with severely reduced cone and rod components suggest that both the cone and rod bipolar cell visual pathways may be disturbed. Slightly decreased a-wave suggests minor abnormality of photoreceptors. It is important to determine whether these patients represent a new clinical entity or a phenotypic variation of an already described retinal disorder.
报告两例患有单侧锥杆功能障碍且a波大于b波（即负型全视野视网膜电图（ERG））患者的检查结果。
进行了标准眼科检查，包括病史采集、最佳矫正视力和眼压测量、裂隙灯生物显微镜检查、检眼镜检查、光谱域光学相干断层扫描、眼底自发荧光、荧光素血管造影和视野检查。使用国际临床视觉电生理学会（ISCEV）标准进行ERG检查。利用患者血清进行免疫印迹分析以确定恢复蛋白1抗体的存在。
这两名患者的共同表现为：单侧发病、男性、老年时突然出现畏光或视力下降、视力保留、无夜盲主诉、眼底外观正常、暗适应3.0 ERG为负型且a波振幅降低、明适应3.0 ERG消失、暗适应0.01 ERG虽极度降低但仍可记录。此外，除了在中央凹半径2.5°范围内的六边形区域外，所有区域的多焦ERG均极度降低。此前已有类似表现的患者报道，但暗适应3.0 ERG的a波低于正常以及光学相干断层扫描（OCT）图像中后极部视网膜广泛形态改变与已报道患者不同。OCT图像显示指状交叉带不清晰和椭圆体带不连续。未检测到抗恢复蛋白抗体。
锥杆成分严重降低的负型ERG提示锥和杆双极细胞视觉通路可能均受干扰。a波轻度降低提示光感受器有轻微异常。确定这些患者是代表一种新的临床实体还是已描述的视网膜疾病的表型变异很重要。
