To statistically analyze the distribution characteristics and related influencing factors of lens decentration and tilt in Chinese patients with age-related cataracts. This cross-sectional study collected basic information and measurement results of patients with age-related cataracts scheduled for surgery. Axial length (AL) was recorded using the IOL Master 700. Corneal topography and lens biometrics were obtained using CASIA 2, and parameters including mean keratometry (Km), keratometric corneal astigmatism, white-to-white distance, horizontal angle-to-angle distance, anterior chamber depth, lens thickness (LT), lens decentration, lens tilt, anterior/posterior lens surface curvature radius (ALR/PLR), and lens equator diameter were documented. Univariate and multivariate regression analyses were conducted to evaluate the correlations between these ocular parameters and lens tilt and decentration. A total of 750 eyes from 750 patients were included. The lens tilted an average of 4.57° towards the inferotemporal direction, with an average decentration of 0.15 mm. Among these, 3.73

Purpose:This prospective cohort study aimed to assess the influence of tear film stability on corneal refractive power measurement and surgical planning in cataract patients. Methods:Participants were divided into tear film instability (tear film stability level 2) and control (level 0-1) groups based on Keratograph 5M results. Using IOL Master 700, two consecutive measurements were obtained with a 10-min interval. Parameters including standard keratometry (Kf, Ks and K), keratometric corneal astigmatism (KCA), total keratometry (TKf, TKs and TK) and total corneal astigmatism (TCA) were recorded. IOL power was calculated using SRK-T, SRK-T TK, Haigis, Haigis TK, Barrett Universal II, and Barrett Universal II TK formulas. Results:The results showed significantly higher differences between two measurements in Kf, K, KCA, TKf, TK, and TCA, as well as the vector variability of corneal astigmatism in the tear film instability group (all P ​< ​0.05). Of all formulas, only the SRK-T formula displayed significantly higher variability in IOL power calculations in the tear film instability group compared to the control group (P ​< ​0.05). Conclusions:This study highlights that tear film instability can lead to deviations in corneal refractive power and astigmatism measurements, contributing to increased prediction errors in IOL power calculation, particularly with the SRK-T formula.

Objective:To compare the difference and consistency of anterior corneal surface and total corneal refractive power and astigmatism measured by CASIA2, IOLMaster 700 and Pentacam in patients with age-related cataract.Methods:A diagnostic test was conducted.Two-hundred patients (200 eyes) with age-related cataract were enrolled in Tianjin Medical University Eye Hospital from March to April 2021.The steep keratometry (Ks), flat keratometry (Kf), mean keratometry (Km), degree and axis of astigmatism of the anterior and the total corneal surface of patients were measured by CASIA2, IOLMaster 700 and Pentacam, respectively.The astigmatism was transformed into J0 and J45 by Fourier transform formula.The differences and correlation of the measurements obtained with the three instruments were analyzed by one-way repeated measures analysis of variance and Pearson correlation analysis.The consistency was evaluated by Bland-Altman test.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Tianjin Medical University Eye Hospital (No.2021KY-07).Results:There were statistically significant differences in anterior corneal surface Kf and J0 measured by the three instruments ( F=18.563, 16.172; both at P=0.001). The Kf measured by CASIA2 was significantly higher than that measured by IOLMaster 700, and the J0 measured by IOLMaster 700 was significantly higher than that measured by Pentacam (both at P<0.05). There were statistically significant differences in total corneal Ks, Kf, Km and J0 measured by the three instruments, which from IOLMaster 700 were the largest, followed by CASIA2, then Pentacam ( F=1 300.447, 1 274.117, 1 609.713, 10.372; all at P=0.001). Pearson correlation analysis showed that the corneal refractive power measured by the three instruments was highly correlated (all at r>0.935, P<0.01), and the correlation of astigmatism values was weaker than the corneal refractive power ( r=0.623-0.908, all at P<0.01). Bland-Altman analysis showed that the three instruments had good consistency in measuring the anterior corneal surface refractive power, anterior corneal surface astigmatism and total corneal astigmatism, which were clinically acceptable, while the consistency of total corneal refractive power measurement was poor.The difference in measuring total corneal refractive power was large between IOLMaster 700 and Pentacam, and relatively small between CASIA2 and Pentacam. Conclusions:The consistency of CASIA2, IOLMaster 700 and Pentacam is good in measuring the anterior corneal surface refractive power of patients with age-related cataract, which can be substitutable, but poor in measuring the total corneal refractive power.The total corneal refractive power measurement from IOLMaster700 is the largest, the smallest from Pentacam, which is not recommended to be clinically exchangeable.

Objective::To evaluate the difference and the consistency of the ocular anterior segment parameters measured with CASIA 2 and IOLMaster 700 in patients with cataract.Methods::In this retrospective study, 95 eyes of 95 patients underwent pre-operative examination for cataract surgery from April 2020 to May 2020 were involved. The central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), keratometry of the steepest meridian (Ks) and keratometry of the flattest meridian (Kf) measured by CASIA 2 and IOLMaster 700 were documented and analyzed using paired t test for differences, Pearson's test for correlation and Bland-Altman test for consistency. Results::The differences of CCT, ACD and LT values measured by CASIA 2 and IOLMaster 700 were statistically significant ( t=-11.94, P<0.001; t=8.52, P<0.001, t=-2.97, P=0.004, respectively), while the differences of Ks and Kf were not statistically significant. The CCT, ACD, LT, Ks and Kf values measured with two instruments were significantly correlated ( r=0.99, 0.99, 0.99, 0.98 and 0.97, all P<0.001). Bland-Altman analysis showed that the mean differences of CCT, ACD and LT were -7.516 μm、0.043 mm、0.023 mm, respectively. The limits of agreement (LoA) were -19.92, 4.48 μm, -0.055, 0.139 mm, -0.120, 0.160 mm. The mean differences of Ks and Kf from the two instruments were 0.028 D and 0.061 D, respectively. The 95% LoA were -0.65, 0.77 D and -0.52, 0.578 D. The proportion outside 95% LoA were 7.36%(7/95) and 6.31% (6/95). The values of CCT, ACD, LT, Ks and Kf measured by the two instruments were not consistent. Conclusion::The CCT, ACD, LT, Ks and Kf measured with CASIA 2 and IOLMaster 700 were not consistent.

Accurate assessment of corneal astigmatism has great clinical implications in procedures such as refractive and cataract surgery. The influence of posterior corneal astigmatism (PCA) on the overall corneal astigmatism assessment was underestimated due to the lack of theoretical understanding and the limitations of examination equipment. In recent years, various devices based on different principles have realized the direct or indirect collection of corneal posterior surface information. Their wide application in clinical and scientific research has made the distribution characteristics and rules of PCA gradually clear. This article reviews the assessment methods and clinical characteristics of PCA, aiming to improve the understanding of these factors and bring attention to them in clinical practice.

目的 基于超声生物显微镜(UBM)图像,通过卷积神经网络(CNN)建立前房角开闭状态的自动识别方法.方法 数据集为我院及所属医联体医院采集的眼科疾病患者的UBM图像.由3名眼科医师手动分为房角开放和房角关闭两类,使用改进后的CNN VGG16模型实现前房角开闭状态的自动识别.结果 该CNN模型对前房角UBM图像的开闭状态识别准确率为0.9619,灵敏度为0.9618,AUC为0.9973.结论 基于CNN模型的前房角开闭状态的自动识别方法准确可靠,为原发性闭角型青光眼的UBM影像自动诊断奠定了实验基础.

目的 基于深度学习(deep learning,DL)和前房角超声生物显微镜(ultrasound biomicroscopy,UBM)图像进行前房角开闭状态的自动识别,为原发性闭角型青光眼的临床自动诊断提供辅助分析.方法 数据集为天津医科大学眼科医院采集的眼科疾病患者的前房角UBM图像,由眼科专家将UBM图像分为房角开放和房角关闭两类,按照6:2:2的比例随机设置训练集、验证集和测试集.为提高深度学习模型的鲁棒性和识别精度,对训练集图像随机进行了旋转、平移和反转等不影响房角形态的数据增强操作.比较VGG16、VGG19、DenseNet121、Xception和InceptionV3网络模型在本文数据集上的迁移学习结果,根据迁移学习结果对VGG16进行卷积层和全连接层的微调,用微调后的VGG16模型实现前房角开闭状态的自动识别.用接收者操作特征曲线下面积和准确率等评价指标对模型识别结果进行定量评价,用类激活热力图可视化模型识别前房角开闭状态时的主要关注区域.结果 类激活热力图表明微调后的VGG16模型识别前房角开闭状态的主要关注区域为房角中心区域,与眼科专家的识别依据一致.该模型的识别准确率为96.19％,接收者操作特征曲线下面积为0.9973.结论 基于深度学习和前房角UBM图像能够以较高的准确率实现前房角开闭状态的自动识别,有利于原发性闭角型青光眼自动诊断技术的发展.

ARVO 2020 : Association for Research in Vision & Ophthalmology Annual Meeting, May 3, 2020 - May 7, 2020, Baltimore, MD, US

Background To introduce a novel protocol to treat refractory acute primary angle closure (APAC): transscleral cyclophotocoagulation (TCP) followed by cataract surgery. Methods Thirteen APAC eyes (13 patients) were enrolled in this prospective case series as study group. All patients underwent emergency TCP (20 pulses of 2000 mW during 2000 ms applied to the inferior quadrant) followed by scheduled cataract surgery. They were compared to 13 age- and gender-matched patients treated with emergency phacotrabeculectomy. We recorded intraocular pressure (IOP), best corrected visual acuity (BCVA), and complications, and several ultrasound biomicroscopy (UBM) parameters before and after TCP. Results In the study group, IOP decreased from 51.5 ± 7.0 mmHg (mean ± standard deviation) before TCP to 16.4 ± 5.4 mmHg 1 day after TCP ( P < 0.001). At 6 months, there was no significant difference in IOP between the study group (14.0 ± 3.4 mmHg) and control group (16.7 ± 4.3 mmHg; P = 0.090); IOP lowering medications were used by 0/13 in the study group and 2/13 patients in the control group ( P = 0.48). At 6 months, there was no significant difference in BCVA between the study group and the control group (20/25 (20/200 to 20/25) and 20/30 (20/50 to 20/25), respectively; P = 1.0). The UBM parameters anterior chamber depth ( P = 0.016), angle-opening distance at 500 μm ( P = 0.011), and maximum ciliary body thickness ( P < 0.001) increased significantly while the iris-ciliary process distance decreased significantly ( P = 0.020) after TCP. Conclusions TCP effectively lowers IOP and modifies the anterior chamber morphology in APAC; TCP followed by cataract surgery can be considered an alternative to treat refractory APAC but needs further evaluation. Trial registration This project was registered in Chinese Clinical Trial Registry ( ChiCTR1800017475 ) at July, 31, 2018 ( http://www.chictr.org.cn/edit.aspx?pid=29629&htm=4 ).

目的比较年龄相关性白内障患者术前Lenstar LS900、iTrace像差仪测量角膜曲率及角膜散光各参数的差异。方法收集我院年龄相关性白内障患者42例(42眼)，术前分别通过Lenstar LS900和iTrace像差仪测量角膜相关参数，包括平坦角膜曲率(运1)、陡峭角膜曲率(运2)、两者的平均值(Km)散光值以及散光轴位，其中将角膜散光通过傅立叶矢量转换公式转换成矢量表示法(J0，J45)进行比较。两种仪器所测数据间的对比采用配对检验，一致性比较采用Bland-Altman分析。结果 Lenstar LS900测量K1、K2、Km、J0和J45分别为(44.206±1.136)、(45.070±1.099)、(44.638±1.079)、(0.032±0.348)、(0.040±0.390)；iTrace像差仪测量K1、K2、Km、J0和J45分别为(44.052±1.233)、(44.986±1.211)、(44.519±1.183)、(-0.043±0.447)、(0.050±0.336)；配对检验，结果显示差异均无统计学意义(=0.551，0.741，0.6330，0.392，0.897，>0.05)。 Bland-Altman分析说明两种仪器的检测结果具有较好的一致性。结论 Lenstar LS900及iTrace像差仪均可以应用于年龄相关性白内障患者术前测量角膜散光的各项参数。

Objective To compare the differences of corneal keratometry and corneal astigmatism measured by Len?star LS900 and KR-1 auto-refractor of age-related cataract. Methods Seventy-six patients with cataract (76 eyes) were in?cluded in this study. Flat keratometry (K1), steep keratometry (K2), mean keratometry (Km) and astigmatism were measured before operation by Lenstar LS900 and KR-1 auto-refractor. The parameters of astigmatism were transformed into J0 and J45 by Fourier vector transform, and which was compared. Results Values of K1, K2, Km, J0 and J45 were (43.960±1.440) D, (44.901±1.319)D, (44.430±1.336)D, 0.043±0.402 and 0.017±0.425 measured by Lenstar LS900, respectively, and which measured by KR-1 auto-refractor were (44.007 ± 1.400)D, (44.859 ± 1.338)D, (44.433 ± 1.330)D,-0.058 ± 0.322 and 0.031 ± 0.419, respectively. There was no statistical difference between these values measured by two instruments ( P>0.05). The Bland-Altman plots showed that two devices had coincident results for corneal parameters. Conclusion Lenstar LS900 and KR-1 auto-refractor can be applied in the measurement of corneal astigmatism of age-related cataract before surgery.