Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, WI, USA.
Am J Ophthalmol. 2012 Dec;154(6):987-1001.e1. doi: 10.1016/j.ajo.2012.06.003. Epub 2012 Sep 7.
To examine retinal structure and changes in photoreceptor intensity after dark adaptation in patients with complete congenital stationary night blindness and Oguchi disease.
Prospective, observational case series.
We recruited 3 patients with complete congenital stationary night blindness caused by mutations in GRM6, 2 brothers with Oguchi disease caused by mutations in GRK1, and 1 normal control. Retinal thickness was measured from optical coherence tomography images. Integrity of the rod and cone mosaic was assessed using adaptive optics scanning light ophthalmoscopy. We imaged 5 of the patients after a period of dark adaptation and examined layer reflectivity on optical coherence tomography in a patient with Oguchi disease under light- and dark-adapted conditions.
Retinal thickness was reduced in the parafoveal region in patients with GRM6 mutations as a result of decreased thickness of the inner retinal layers. All patients had normal photoreceptor density at all locations analyzed. On removal from dark adaptation, the intensity of the rods (but not cones) in the patients with Oguchi disease gradually and significantly increased. In 1 Oguchi disease patient, the outer segment layer contrast on optical coherence tomography was 4-fold higher under dark-adapted versus light-adapted conditions.
The selective thinning of the inner retinal layers in patients with GRM6 mutations suggests either reduced bipolar or ganglion cell numbers or altered synaptic structure in the inner retina. Our finding that rods, but not cones, change intensity after dark adaptation suggests that fundus changes in Oguchi disease are the result of changes within the rods as opposed to changes at a different retinal locus.
观察完全性先天性静止性夜盲症和 Oguchi 病患者在暗适应后视网膜结构和光感受器强度的变化。
前瞻性、观察性病例系列研究。
我们招募了 3 名因 GRM6 基因突变导致的完全性先天性静止性夜盲症患者、2 名因 GRK1 基因突变导致的 Oguchi 病兄弟患者和 1 名正常对照者。从光学相干断层扫描图像中测量视网膜厚度。使用自适应光学扫描激光检眼镜评估视杆和视锥马赛克的完整性。我们对 5 名患者进行了一段时间的暗适应后成像，并在 1 名 Oguchi 病患者在明适应和暗适应条件下检查了光相干断层扫描的层反射率。
GRM6 基因突变患者的旁中心区视网膜厚度降低，原因是内层视网膜厚度变薄。所有患者在所有分析位置的光感受器密度均正常。从暗适应中移除后，Oguchi 病患者的视杆（而非视锥）强度逐渐显著增加。在 1 名 Oguchi 病患者中，光相干断层扫描的外节层对比度在暗适应下比明适应下高 4 倍。
GRM6 基因突变患者内层视网膜的选择性变薄提示双极细胞或节细胞数量减少或内视网膜的突触结构改变。我们发现暗适应后视杆而非视锥强度发生变化，表明 Oguchi 病眼底变化是视杆内变化的结果，而不是视网膜其他部位的变化。
