Department of Ophthalmology and Optometry, Medical University Vienna, Vienna, Austria.
Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
Invest Ophthalmol Vis Sci. 2021 Apr 1;62(4):24. doi: 10.1167/iovs.62.4.24.
To study birefringence of the peripapillary retinal nerve fiber layer (RNFL) of diabetic eyes with no clinical signs of diabetic retinopathy (DR) or mild to moderate DR stages using spectral-domain polarization-sensitive (PS) optical coherence tomography (OCT).
In this observational pilot study, circular PS-OCT scans centered on the optic nerve head were recorded in prospectively recruited diabetic and age-matched healthy eyes. From averaged circumpapillary intensity and retardation tomograms plots of RNFL birefringence were obtained by a linear fit of retardation versus depth within the RNFL tissue for each A-scan position and mean birefringence values for RNFL calculated. Spectral-domain OCT imaging (Heidelberg Engineering) was performed to assess peripapillary RNFL thickness and macular ganglion cell complex (GCC).
Out of 70 eyes of 43 diabetic patients (mean ± SD age: 50.86 ± 15.71) 36 showed no signs of DR, 17 mild and 17 moderate nonproliferative DR with no diabetic macular edema. Thirty-four eyes of 34 healthy subjects (53.21 ± 13.88 years) served as controls. Compared with healthy controls (0.143° ± 0.014°/µm) mean total birefringence of peripapillary RNFL was significantly reduced in subclinical diabetic eyes (0.131° ± 0.014°/µm; P = 0.0033), as well as in mild to moderate DR stages (0.125° ± 0.018°/µm, P < 0.0001) with borderline statistically significant differences between diabetic patients (P = 0.0049). Mean birefringence values were significantly lower in inferior compared with superior RNFL sectors (P < 0.0001) of diabetic eyes with no such difference detected in the healthy control group.
We identified evidence of early neuroretinal alteration in diabetic eyes through reduced peripapillary RNFL birefringence assessed by PS-OCT occurring before appearance of clinical microvascular lesions or GCC alterations.
使用谱域偏振敏感（PS）光学相干断层扫描（OCT）研究无临床糖尿病视网膜病变（DR）或轻度至中度 DR 阶段的糖尿病患者的视盘周围视网膜神经纤维层（RNFL）的双折射。
在这项前瞻性观察性试点研究中，对前瞻性招募的糖尿病和年龄匹配的健康眼中以视神经头为中心的圆形 PS-OCT 扫描进行了记录。从平均视盘周围强度和视网膜神经纤维层双折射延迟断层图中，通过对每个 A 扫描位置的 RNFL 组织内的延迟与深度进行线性拟合，获得 RNFL 双折射的图。使用光谱域 OCT 成像（Heidelberg Engineering）评估视盘周围 RNFL 厚度和黄斑神经节细胞复合体（GCC）。
在 43 例糖尿病患者的 70 只眼中（平均±标准差年龄：50.86±15.71），36 只眼无 DR 迹象，17 只眼为轻度非增生性 DR，17 只眼为中度非增生性 DR，无糖尿病性黄斑水肿。34 只眼的 34 只健康对照（53.21±13.88 岁）作为对照。与健康对照组（0.143°±0.014°/µm）相比，亚临床糖尿病患者的视盘周围 RNFL 的总双折射明显降低（0.131°±0.014°/µm；P=0.0033），轻度至中度 DR 阶段（0.125°±0.018°/µm，P<0.0001），糖尿病患者之间的差异具有统计学意义（P=0.0049）。在糖尿病患者中，下象限 RNFL 的双折射值明显低于上象限 RNFL（P<0.0001），而在健康对照组中则未发现这种差异。
我们通过 PS-OCT 评估发现，在出现临床微血管病变或 GCC 改变之前，糖尿病患者的视盘周围 RNFL 双折射降低，这表明存在早期神经视网膜改变。
