Angmo Dewang, Bhartiya Shibal, Mishra Sanjay K, Sharma Reetika, Poojari Amar, Dada Tanuj
Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences.
Nepal J Ophthalmol. 2014 Jul-Dec;6(2):185-91. doi: 10.3126/nepjoph.v6i2.11692.
Before any new device can replace another for use in clinical practice, it is imperative that its reproducibility, diagnostic accuracy, and ability to detect changes over time are tested.
To evaluate retinal nerve fiber layer (RNFL) measurements between two optical coherence tomography (OCT) systems: the Stratus OCT, a time domain system, and the Cirrus HD-OCT, a spectral domain system (both by Carl Zeiss Meditec, Inc., Dublin, CA).
An observational cross-sectional study was carried out involving 20 eyes with primary open angle glaucoma and 32 eyes of healthy controls. One eye of each patient was imaged on the same day with each instrument. The RNFL thicknesses measured by the two instruments were compared.
Each clock hour, quadrant, and average RNFL thickness was determined on each of the two instruments.
The reliability was assessed by the intra-class correlation coefficient (ICC) and the Bland Altman plot for the limits of agreement for the overall mean RNFL thickness and for each quadrant.
A randomly selected eye of each of the 52 participants was analyzed. The mean temporal, superior, nasal and inferior RNFL thickness (in microns) were found to be 65.42±18.98, 114.85±26.67, 75.83±28.61 and 116.35±29.43 when measured by the Stratus OCT. In glaucoma patients these values were 55.06±18.22, 97.86±29.37, 63.44±24.89, and 102.94±38.20; and in controls these values were 70.59±17.40, 123.61±20.65, 82.03±28.67 and 123.06±21.63 respectively. The mean temporal, superior, nasal and inferior RNFL thickness (in microns) were 62.00±13.08, 112.00±25.13, 68.56±16.66 and 114.23±25.82 respectively, when measured with the Cirrus OCT. In glaucoma patients these values were 57.88±12.99, 98.56±26.88, 64.63±12.52 and 105.50±29.49; while in the control group these were 64.06±12.82, 118.72±21.63, 70.53±18.33, and 118.59±23.05 respectively. Intraclass correlation coefficient alpha (ICC alpha) for the temporal, superior, nasal and inferior quadrant RNFL thickness measurements were 0.81, 0.85, 0.66 and 0.93 respectively. Bland-Altman plots showed the limits of agreement (95%CI) for average RNFL to be 4.59±20.10 in the control group. In patients of glaucoma, Bland-Altman plots showed the limits of agreement (95%CI) for average RNFL to be 1.56±21.50.
There is considerable variability in the RNFL thickness measurements made by the Cirrus and Stratus OCT that exceeds the limits of resolution afforded by the instruments. RNFL measurements obtained from the two OCT systems may not be used interchangeably.
在任何新设备能够替代另一设备用于临床实践之前，测试其可重复性、诊断准确性以及随时间检测变化的能力是至关重要的。
评估两种光学相干断层扫描（OCT）系统之间视网膜神经纤维层（RNFL）的测量结果：时域系统Stratus OCT和光谱域系统Cirrus HD - OCT（均由加利福尼亚州都柏林的卡尔·蔡司医疗技术公司生产）。
进行了一项观察性横断面研究，纳入20只原发性开角型青光眼患者的眼睛和32只健康对照者的眼睛。每位患者的一只眼睛在同一天用每种仪器进行成像。比较两种仪器测量的RNFL厚度。
确定两种仪器上每个钟点、象限以及平均RNFL厚度。
通过组内相关系数（ICC）和Bland - Altman图评估总体平均RNFL厚度及每个象限一致性界限的可靠性。
对52名参与者中随机选择的一只眼睛进行了分析。用Stratus OCT测量时，颞侧、上方、鼻侧和下方RNFL的平均厚度（以微米为单位）分别为65.42±18.98、114.85±26.67、75.83±28.61和116.35±29.43。在青光眼患者中，这些值分别为55.06±18.22、97.86±29.37、63.44±24.89和102.94±38.20；在对照组中，这些值分别为70.59±17.40、123.61±20.65、82.03±28.67和123.06±21.63。用Cirrus OCT测量时，颞侧、上方、鼻侧和下方RNFL的平均厚度（以微米为单位）分别为62.00±13.08、112.00±25.1
