Law Simon K, Kornmann Helen L, Nilforushan Naveed, Moghimi Sasan, Caprioli Joseph
Division of Glaucoma, Jules Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA.
J Glaucoma. 2016 Jan;25(1):27-32. doi: 10.1097/IJG.0000000000000072.
To compare the accuracy of the "ISNT" rule [neural rim width of inferior(I)≥superior(S)≥nasal(N)≥temporal(T) regions] and the abbreviated variant, the "IS" rule (inferior≥superior regions) to differentiate normal from glaucomatous eyes.
Medical records of patients who were evaluated in 2011, had glaucomatous optic neuropathy and visual field defects, on glaucoma treatment, and had stereoscopic optic disc photographs were reviewed. Optic discs with focal complete loss of neural rim or long axis rotated >30 degrees from vertical meridian, and patients with ≥5 D of myopia or any retinal pathology or nonglaucomatous optic neuropathy were excluded. One eye per patient was randomly enrolled. Normal control eyes were also included. Rim widths were measured with an image processing program (ImageJ, National Institutes of Health) in a masked manner. The sensitivity and specificity of the ISNT rule, the IS rule, and cup-to-disc ratio (CDR) were compared.
A total of 134 glaucoma and 110 normal eyes were enrolled. The mean CDRs of the glaucoma and normal eyes were 0.65±0.13 and 0.39±0.15, respectively. Sensitivities of the ISNT and IS rules were 85% and 41%, respectively, whereas specificities were 46% and 85%, respectively. Application of the IS rule in eyes with larger CDR (>0.57) increased the specificity of the IS rule to 93% while keeping the sensitivity at 41%. When ISNT or IS rule and CDR>0.57 were combined in differentiating normal from glaucomatous eyes for the entire sample, specificities approached 90% and 99%, respectively.
The ISNT rule alone has a high sensitivity but relatively low specificity. Application of the IS rule in eyes with increased CDR yields a much higher specificity for differentiating normal from more advanced glaucomatous eyes. A combination of different features of the optic disc (increase of CDR and ISNT or IS rule) improves the specificity of optic disc evaluation for glaucoma.
比较“ISNT”规则[下方（I）神经纤维层宽度≥上方（S）≥鼻侧（N）≥颞侧（T）区域]及其简化变体“IS”规则（下方≥上方区域）区分正常眼与青光眼性眼的准确性。
回顾2011年接受评估、患有青光眼性视神经病变和视野缺损、正在接受青光眼治疗且有立体视盘照片的患者的病历。排除神经纤维层局部完全缺失或长轴与垂直子午线旋转>30度的视盘，以及近视度数≥5D或有任何视网膜病变或非青光眼性视神经病变的患者。每名患者随机选取一只眼睛。还纳入了正常对照眼。使用图像处理程序（美国国立卫生研究院的ImageJ）以盲法测量神经纤维层宽度。比较ISNT规则、IS规则和杯盘比（CDR）的敏感性和特异性。
共纳入134只青光眼眼和110只正常眼。青光眼眼和正常眼的平均杯盘比分别为0.65±0.13和0.39±0.15。ISNT规则和IS规则的敏感性分别为85%和41%，而特异性分别为46%和85%。在杯盘比>0.57的眼中应用IS规则可将IS规则的特异性提高到93%，同时敏感性保持在41%。当将ISNT或IS规则与杯盘比>0.57结合用于区分整个样本中的正常眼与青光眼性眼时，特异性分别接近90%和99%。
单独使用ISNT规则敏感性高但特异性相对较低。在杯盘比增加的眼中应用IS规则在区分正常眼与更晚期青光眼性眼时具有更高的特异性。视盘不同特征（杯盘比增加以及ISNT或IS规则）的组合可提高青光眼视盘评估的特异性。
