Prevalence and risk factors for eye diseases, blindness, and low vision in Lhasa, Tibet

AIM: To determine the prevalence and risk factors for eye diseases, blindness, and low vision in Tibet, and to assist the development of eye disease prevention and treatment schemes.METHODS: We carried out a survey of eye diseases among a population living at high altitude. A total of 1 115 Tibetan permanent residents aged 40 years or older from the towns and villages of Qushui County, Lhasa Prefecture, Tibet Autonomous Region, participated in this study. All participants completed a detailed questio-nnaire, and underwent presenting and pinhole visual acuity tests,and a comprehensive ophthalmic examination.RESULTS: There were 187 blind eyes (8.43%), 231 eyes with low vision (10.41% ). The leading cause of visual impairment was cataract of 55.0% (101/187) blindness and of 50.2% (116/231) low vision, followed by fundus lesions of 22.9% blindness and 23.8% low vision, while only a low prevalence of glaucoma of 9.6% blindness and 1.7% low vision was observed. The analysis of 2 219 eyes showed that the most common external eye disease was pterygium (27.2%) in Tibet.CONCLUSION: The high prevalence of blindness and low vision in the Tibetan population at high altitude is a serious public health issue. There is a need to establish and maintain an appropriate effective eye care program in Tibet.

Validity and reliability study of Turkish version on low vision with quality of life questionnaire

AIM:To adapt the low vision-related quality of life(LVQOL) instrument into Turkish language and to assess its validity and reliability.METHODS:The study was conducted in 387 patients attending the Centre of Low Vision Rehabilitation,Faculty of Medicine,Ankara University.For statistical analyses,the Spearman's correlation coefficient,Cronbach's alpha coefficient and Confirmatory Factor Analysis(CFA) were used.RESULTS:According to results of CFA,the item in the 'Adjustment' subscale because of having the factor loading below 0.40,was excluded from the questionnaire.The reliability of the questionnaire was assessed according to Cronbach's alpha coefficients.The reliability of the 'Distance Vision,Mobility,and Lighting' subscale was ?琢=0.863;of the 'Adjustment' subscale was ?琢=0.694;'Reading and Fine Work' was ?琢=0.791,and 'Activities of Daily Living' was ?琢= 0.770.So these results indicate that the questionnaire is reliable to measure the vision related quality of life of low-vision patients.The correlations between the subscales were also analyzed,and the correlation between 'Adjustment' and 'Reading and Fine Work' was found to be the lowest(rs=0.336,P <0.001),whereas the strongest correlation was found between the 'Reading and Fine Work',and 'Activities of Daily Living'.Additionally,the 'Adjustment' dimension showed the strongest correlation with only 'Distance Vision,Mobility,and Lighting' dimension.CONCLUSION:After removing the last item in the second dimension,the Turkish adaptation of all dimensions of the LVQOL has been shown to be reliable,valid and suitable for use in patients with low vision in Turkey.

VISUAL REHABILITATION IN LOW VISION PATIENTS WITH AGE-RELATED MACULAR DEGENERATION

Using optical visual aids, visual rehabilitation was performed in 14 low vision patients(25 eyes) with age-related macular degeneration. With distance aids, visual acuity improvement appeared in 24 eyes(95%) out of the 25 eyes. Twelve eyes(48%) obtained a visual acuity equal to or better than 0.4. With near visual aids, near acuity of all eyes(100%) was improved. Thirteen eyes(52%) got the near vision equal to or better than 0.5. Ten patients could read No.5 Chinese Reading Card. The reading success rat...

Responsiveness and minimal clinically important difference of the Chinese version of the Low Vision Quality of Life Questionnaire after cataract surgery

AIM: To investigate the Chinese version of the Low Vision Quality of Life Questionnaire(CLVQOL) as an instrument for obtaining clinically important changes after cataract surgery.METHODS: Patients underwent cataract surgery in Shanghai General Hospital, Shanghai Jiao Tong University, who fit the inclusion criteria were recruited. Two CLVQOLs were administered, including a preoperative CLVQOL and a CLVQOL at the end of the 3 mo follow-up period, and were completed using face-to-face interviews or phone interviews conducted by trained investigators. The minimal clinically important difference(MCID) was calculated using an anchor-based method and a distribution method. In addition, the responsiveness of the questionnaire was measured.RESULTS: A total of 155 residents were enrolled. The average visual acuity(VA) preoperatively was 0.08(SD=0.05), and it increased to 0.47(SD=0.28) at the end of followup. Statistically significant positive changes in the CLVQOL scores indicated significant improvement of vision related quality of life after cataract surgery. With the larger value between the two results as the final value, the MCID values of the CLVQOL(scores of the four scales as well as the total score) were 8.94, 2.61, 4.34, 3.10 and 17.63, respectively. The CLVQOL has both good internal and external responsiveness.CONCLUSION: CLVQOL scores are appropriate instruments for obtaining clinically important changes after cataract surgery. This study is an effective exploration for establishingcataract surgery efficacy standards, which helps clinical and scientific research workers in ophthalmology to gain a more in-depth understanding when using CLVQOL.

Functional outcome of the low vision aids for visual impairment secondary to central nervous system tumors in children

To assess functional outcomes of optical low vision aids(LVAs) for pediatric visual impairment due to central nervous system(CNS) tumors. A prospective case study was conducted on 15 children with history of CNS tumors with mean age of 10.47±1.85 y. Lighthouse distance, near visual acuity tests, cycloplegic refraction, reading speed measurement and visual field examination were done. Prescription of far and near LVAs followed by training sessions. LVPrasad-functional vision questionnaire was done to evaluate performance. Visual impairment was moderate(13.3%), severe(73.3%), profound(6.7%) and near blindness in 6.7%. Telescopes prescribed in 33.4%, video magnifier in 46.7%. Questionnaire scores were significantly improved for distant rather than near tasks(P≤0.05) after training. LVAs rehabilitation is an effective method of improving vision in pediatric visual defects secondary to CNS tumors.

Low Vision Assessment: Complications from Juvenile Rheumatoid Arthritis

Background: Juvenile Rheumatoid Arthritis (JRA) is an inflammatory disease that affects the joints of children and is associated with ocular complications, like uveitis and cataract. Patients with such complications can benefit from a low vision assessment to improve their functionality and their quality of life. In this case study, the importance of early detection and management of ocular complications of JRA, as well as visual rehabilitation through a low vision assessment, are highlighted and discussed. Case Presentation: A 12-year-old female of East Indian descent presented to the Low Vision Center of the University of the West Indies Optometry Eye Unit, bilaterally aphakic (absence of crystalline lens) as a result of complications she developed secondary to a systemic condition diagnosed as JRA. She presented with a distance visual acuity of 2.30 logMAR in the RE, and 1.64 logMAR in the LE, at near she was able to read 8.0 M and 3.2 M at a distance of 8 cm for RE & LE respectively. She has a history of ocular disorder secondary to JRA such as cataract, uveitis, upon low vision assessment a new spectacle prescription and an illuminated stand magnifier of 8D was issued, the patient was satisfied with the outcome of the treatment, management and low vision device issued. Conclusion: At the end of the low vision assessment, the patient was extremely satisfied and looked forward to the prospect of returning to school. Although JRA can have severe ocular complications, with the correct management, a patient’s quality of life can be dramatically improved thus stressing the importance of these types of visual assessments.

The Contrast Sensitivity Function in Low Vision

The contrast sensitivity of 51 low vision patients (95 eyes) showed a substantial decrease in all spatial frequencies. The peak contrast sensitivity was shifted to 1 C/D from the normal 3-4 C/D. The high-frequency cut off is correlated to the visual acuity positively. Of the 33 patients, the preferred eye was the eye with better peak sensitivity in 28 patients (84%), while the preferred eye was the eye with better visual acuity in 22 patients (66%). It seems that the peak sensitivity is more important t...

Quantitative Evaluation of Flicker ERG Waveforms in Low Vision Patients

Flicker electroretinograms(FERGs)of 30Hz were recorded for 46eyes(23 cases)of low vision,including 38 eyes with retinal diseases and 8eyes with optic neuropathy,and for 39 normal eyes(33 cases).The recordedwave forms were analysed by two methods:(1)to measure the peak to peakamplitude and pseudophase directly,and(2)to measure the amplitude andphase of fundamental response component(30Hz)by discrete Fourier trans-form(DFT).The abnormality ratios between these two methods were com-pared in low vision pati...

AB097.Barriers and facilitators related to the use of optical low vision aids,a scoping review

Background:In recent decades,several studies have been performed in the field of(non-)use of assistive technology devices(ATs)and have found that many variables are likely to be involved in the decision-making process of whether a person with a disability uses or abandons their aids.In low vision rehabilitation,high variability rates and a variety of reasons for non-use of low vision aids has been reported.Determinants of non-use of ATs have previously been categorized into personal factors,ATs factors,environmental factors of the user,and intervention factors.It is probable that some of these factors are also associated with the use of optical low vision aids(OLVAs).Thus,using a framework about adherence with medical interventions,the aim of this scoping review was to explore barriers and facilitators related to OLVAs(non-)use.Methods:Existing guidelines of the scoping review Methods were used to examine and summarize the extent,range,and nature of findings regarding factor categories associated to OLVAs usage.Searches were conducted using the following online databases:Embase,MedLine,and ERIC without limitation on publication dates.A combination of key words and MeSH terms was used based upon the identified core concepts of the research question:(I)low vision;(II)assistive technology;and(III)adherence.A charting form,a flow chart of the study selection process,and a combination of a descriptive numerical analysis and a thematic analysis of 24 studies were performed.Results:The results of this review indicate high variability rates(range:13-50%,M=24%,SD=10%)of people possessing OLVAs but not using them.Most authors do not use a precise definition of“non-use”,and when a definition is provided,the terminology is inconsistent.As expected,the four categories of variables identified are likely to be involved in OLVAs’(non-)use:(I)the largest number of concerns were personal factors.Several aspects regarding personal characteristics were identified,such as demographic,physical,psychological,social-emotional,and occupational factors.Some variables,such as age,diagnosis and visual acuity were reported as contradictorily influencing the OLVAs’usage;(II)ATs factors were associated with quality,appearance,practical aspects of use and the very type of OLVAs;(III)environmental factors referred to social support,physical barriers,expectations of the social environment,presence of a helper,and stigmatization;(IV)finally,intervention factors consisted of taking into account user’s opinions,positive health care experiences,instruction and training,provision processes,delivery periods,and follow-up services.Conclusions:This scoping review provides the preliminary evidence that factors related to OLVAs non-use could be classified into the same four typical categories described in the theory of non-adherence.These results suggest that strategies intended to enhance adherence might be for OLVAs should focus on these four aspects of device use.

Profile of Low Vision Patients in a Resource-Poor Underserved Setting of a Developing Country

Objectives: To identify causes of low vision among the patients in the Eye clinic of University of Nigeria Teaching Hospital (UNTH). Methods: This was a cross-sectional study of all new consecutive low vision patients seen at the eye clinic of University of Nigeria Teaching Hospital-(UNTH) Ituku-Ozalla. All patients with low vision were evaluated by the researcher and the findings entered on a research protocol. Data were analyzed using descriptive statistics to generate frequency and percentage distributions and analytical statistics to test for significance of observed inter-group differences. In all comparisons, statistical significance was indicated by p < 0.05. Results: A total of 197 patients were seen comprising of 120 males and 77 females (M:F = 1.6:1) aged 39.3 ± 22.9 SD years. The main causes of low vision in the study population were glaucoma (36.0%), followed by oculocutaneous albinism (14.7%). The mean presenting distant VA was logMAR 1.1 (95% CI), while the mean near VA is logMar 1.0 (6/60, 20/200). After refraction, the mean distant VA was logMar 1.0, using unpaired t-test, the difference between the distant presenting and refracted VA were not statistically significant. 57.9% had distant VA after optical low vision assessment of logMar 0.9 - logMar - 0.2 while the mean distant VA was logMar 0.8 which was statistically significant. Near vision after optical assessment improved with a mean of logMar 0.8, which was statistically significant. Conclusion: Glaucoma was the commonest cause of low vision in this study. Optical low vision aids improved the visual functions of majority of the patients in this study.

Prevalence of Charles Bonnet syndrome in low vision:a systematic review and meta-analysis

Background:Charles Bonnet syndrome(CBS)is characterized by vivid lifelike visual hallucinations and is typically seen in individuals with visual impairment.In this systematic review,we summarize current knowledge on the prevalence of CBS in patients with low vision.Methods:We searched 11 literature databases on 21 April 2021 for studies on the prevalence of CBS in low vision populations.Our protocol was registered in the PROSPERO database(reg.No.CRD42021255021).Eligible studies were defined as those on a population of low vision patients wherein the prevalence of CBS was evaluated(without any further restriction on the method for diagnosis of CBS).No restriction was enforced on study design,but we expected observational cross-sectional studies due to the nature of our research question.Two authors independently extracted data and evaluated risk of bias of individual studies using the Agency for Healthcare Research and Quality checklist for cross-sectional studies.Studies underwent qualitative review in the text and quantitatively in a prevalence meta-analysis using the random-effects model.Sensitivity analysis was made to evaluate the robustness of the summary estimate.Results:We identified 11 studies,which summarized data on 4,521 individuals with visual impairment.Diagnosis of CBS was based on screening questions or interviews,which in positive cases often was explored in more detail with follow-up questions or interviews.Most studies either had normal mental state as a participant eligibility criterion or as a part of the diagnosis of CBS.The pooled prevalence of CBS in low vision patients aged≥40 years was 19.7%(95%CI:13.8%to 26.4%).The sensitivity analysis showed certain robustness in the summary prevalence estimate wherein prevalence estimates ranged from 16.9%to 22.5%.Conclusions:CBS is a prevalent condition in patients with low vision at a rate of approximately one in five patients.Considering that an estimated 239 million individuals have moderate visual impairment or worse,we estimate a global number of patients with CBS at approximately 47.2 million.

基于计算机视觉的腰背痛患者痧象图片处理和分析研究

目的提出痧象图片处理和分析的思路和方法,为痧象数字化研究提供参考。方法以计算机视觉技术为基础,以腰背痛患者背部痧象处理和分析为目标,提出痧象图片预处理、特征提取和筛选、痧象分析等系列方法,并进行实验验证。结果痧象预处理方法能够实现原始图像颜色校正和背部区域精准分割;特征提取方法提取了腰背痛患者94个痧象颜色和纹理特征,筛选得到20个关键特征;痧象分析方法能够找到与不同证候相关的关键特征。结论利用计算机视觉方法能够较好地完成痧象图片的预处理、特征识别和提取、痧象分析和理解,可以为痧象数字化和客观化研究提供支撑。

基于低空视觉的直升机旋翼轴心轨迹测量法

为满足直升机飞行状态旋翼轴心轨迹测量需求,提出了一种基于低空双目视觉的轴心轨迹测量方法。首先,针对高速旋转体的小量测量,基于立体视觉测量原理设计构建了以无人机为低空移动平台的旋翼轴心轨迹视觉测量系统。其次,针对动-动测量环境条件,提出了地面标定与空中动态实时标定联合的测量系统标定方法。然后,基于空间几何关系,论述了旋翼轴心静态估计与动态轨迹测量方法;最后,进行了测量系统地面精度验证试验与直升机地面开车状态的旋翼轴心轨迹测量试验。试验结果表明,该方法准确可靠,点间距离精度优于1‰,可实现轴心轨迹的非接触精确测量,还可推广应用于其他动态小量测量任务。

低视力患者一般自我效能感LPA及其与生存质量的关系研究

目的探究低视力患者一般自我效能感潜在类别,探讨不同潜在类别与生存质量的关系及生存质量的影响因素。方法采用横断面临床研究设计,纳入2021年5月—2022年4月在首都医科大学附属北京同仁医院就诊的低视力患者234例(289只眼),采用一般自我效能感量表(GSES)和中文版低视力生存质量量表(CLVQOL)进行调查,使用Mplus8.0和SPSS 26.0统计学软件分析一般自我效能感潜在类别及与生存质量的关系,采用多重线性回归法分析生存质量的影响因素。结果(1)剖面分析结果:当一般自我效能感潜在剖面数为3时,艾凯克信息准则(AIC)、贝叶斯信息准则(BIC)、调整贝叶斯信息准则(aBIC)值最大,entropy更接近1,剖面3为最佳模型。(2)类别特点及命名:本研究中的低视力患者分为3个潜在类别,类别1(23.9%)一般自我效能感水平最高,命名为高效能感型;类别2(54.7%)位于整体得分的中间水平,命名为中效能感型;类别3(21.4%)一般自我效能感得分最低,命名为低效能感型。(3)类别的基本特征:一般自我效能感不同潜在类别的低视力患者基本特征比较显示,年龄(χ^(2)=16.727,P=0.033)、文化程度(χ^(2)=11.389,P=0.023)、医疗费用来源(χ^(2)=27.914,P=0.000)、户籍类型(χ^(2)=16.503,P=0.002)、视力损伤时长(χ^(2)=36.607,P=0.000)、职业类型(χ^(2)=11.207,P=0.004)、视力(χ^(2)=19.433,P=0.001)和既往眼部手术史(χ^(2)=8.293,P=0.016)在3个不同潜在类别间的差异均有统计学意义,其他社会人口学特征差异均无统计学意义(P>0.05)。(4)类别与生存质量的关系:不同自我效能感潜在类别的低视力患者生存质量总分比较,差异有统计学意义(F=8.187,P=0.000),生存质量各维度比较显示,远视力、移动、光感(F=6.057,P=0.003)、阅读和精细工作(F=9.648,P=0.000)、调节能力(F=5.214,P=0.007)、日常生活能力(F=8.164,P=0.000),差异均有统计学意义。(5)生存质量影响因素的多因素分析:视力(t=-6.582,P=0.000)、一般自我效能感不同潜在类别(t=-2.092,P=0.039)为生存质量的独立影响因素,差异均有统计学意义。结论低视力患者的一般自我效能感存在异质性,应重点关注低效能感型和视力受损严重的低视力患者,探索一般自我效能感干预策略,提高其生存质量水平。

视觉Transformer在低级视觉领域的研究综述

Transformer是一种革命性的神经网络模型架构,最初为自然语言处理而设计,但其由于卓越的性能,在计算机视觉领域获得了广泛的应用。虽然关于Transformer在自然语言处理领域的应用有大量的研究和文献,但针对低级视觉任务的综述相对匮乏。简要介绍了Transformer的原理并分析归纳了几种变体。在低级视觉任务的应用方面,将重点放在图像恢复、图像增强和图像生成这三个关键领域。通过详细分析不同模型在这些任务中的表现,探讨了它们在常用数据集上的性能差异。对Transformer在低级视觉领域的发展趋势进行了总结和展望,提出了未来的研究方向,以进一步推动Transformer在低级视觉任务中的创新和发展。这一领域的迅猛发展将为计算机视觉和图像处理领域带来更多的突破,为实际应用提供更加强大和高效的解决方案。

一种面向机器视觉感知的暗光图像增强网络

低光照等恶劣环境下的目标检测一直都是难点,低光照和多雾因素往往会导致图像出现可视度低、噪声大等情况,严重干扰目标检测的检测精度。针对上述问题,提出了一个面向机器视觉感知的低光图像增强网络MVP-Net,并与YOLOv3目标检测网络整合,构建了端到端的增强检测框架MVP-YOLO。MVP-Net采用了逆映射网络技术,将常规RGB图像转换为伪RAW图像特征空间,并提出了伪ISP增强网络DOISP进行图像增强。MVP-Net旨在发挥RAW图像在目标检测中的潜在优势,同时克服其在直接应用时所面临的限制。模型在多个真实场景暗光数据上取得了优于先前工作效果并且能够适应多种不同架构的检测器。其端到端检测框mAP(50%)指标达到了78.3%,比YOLO检测器提高了1.85%。

基于机器视觉的低对比度工件轮廓尺寸标定方法

受照明不均匀和图像噪声的影响,低对比度工件的轮廓可能不连续且边缘模糊,导致尺寸参数标定结果误差增加,影响了工件尺寸参数的准确性。针对这个问题,引入机器视觉技术来改善工件轮廓的清晰度和准确性。首先,通过摄像机和相关设备的布置,获取工件的图像,针对低对比度可能存在的噪声,采用正交处理方法对图像进行降噪以提高图像质量;接下来,基于预处理图像提取工件表面形态与轮廓信息,为尺寸参数标定提供参考和基准。为了进行标定,采用一维标靶的设计,建立相机平面到一维标靶平面的空间映射路径。在这个映射路径下将工件轮廓映射到二维平面坐标上,实现尺寸标定。对比实验结果表明:设计的方法应用效果良好,可以标定低对比度工件轮廓尺寸,标定后的工件轮廓尺寸与设计值的误差小于1 mm,提高工件的加工、生产制造精度。

从局部到全局的零参考低照度图像增强方法

为解决现有的低照度图像增强方法存在的色彩失真、细节损失以及暗区增强不足和亮区增强过度导致低照度图像增强效果不理想的问题,提出了一种从局部到全局的零参考低照度图像增强方法。采用局部照度增强对低照度图像进行像素级增强,改进了自适应光照映射估计函数,提升了照度调整能力,避免了生成大量的迭代参数,提高了模型的推理速度;采用基于Transformer结构的全局图像调整对局部增强后的图像进行全局调整,解决了亮区照度增强过度的曝光问题和暗区照度增强不足的问题,提升了图像的整体对比度;优化损失函数,对低照度图像特征和增强图像特征进行相似性约束,提升了目标检测精度。实验结果表明,LOL数据集上的客观指标峰值信噪比和结构相似性达到了20.18 dB和0.80,MIT-Adobe FiveK数据集上达到了23.31 dB和0.87,ExDark数据集上增强后图像的目标检测精度提高了7.6%,有效提升了低照度图像可视化质量和目标检测效果。

“互联网+中医护理服务”对低视力病人生活质量的影响

目的:探讨“互联网+中医护理服务”对低视力病人生活质量的影响。方法:选取2020年9月—2022年9月中国中医科学院眼科医院内障眼病科收治的100例低视力病人作为研究对象,采用随机数字表法将病人分为试验组及对照组,每组50例。对照组采用常规中医护理,试验组在对照组基础上采用“互联网+中医护理服务”。比较两组病人干预前及干预3个月后焦虑、生活质量、自理能力。结果:试验组病人干预3个月后生活质量评分为(58.90±6.35)分,高于干预前[(34.98±5.13)分]及同期对照组[(37.98±6.24)分];自理能力评分为(71.66±4.62)分,高于干预前[(53.46±5.27)分]及同期对照组[(61.50±4.77)分];焦虑评分为(46.94±6.99)分,低于干预前[(55.12±8.85)分]及同期对照组[(52.62±7.35)分],差异均有统计学意义(P<0.05)。结论:采用“互联网+中医护理服务”能有效改善低视力病人生活质量、自理能力及焦虑状态。

极低频数据中的Pc1地磁脉动自动识别

极低频电磁台网成功观测到大量的Pc1地磁脉动事件,研究极低频Pc1地磁脉动的自动识别方法对于全面分析地球空间电磁物理环境具有重要意义.本文采用了YOLOv8目标检测网络、ResNet残差网络和定向特征增强技术,提出了一种基于计算机视觉的Pc1地磁脉动自动识别模型(Automatic Detection Model for Pc1 Geomagnetic Pulsation,简称ADM-Pc1).以大连台站和丽江台站的极低频观测数据为例,利用2015—2016年的数据作为训练集进行模型的监督学习,并使用2017—2022年的数据作为测试集对模型性能进行评估.实验结果显示,ADM-Pc1模型的F1-Score值达到了95%,错分率仅为0.9%,虚警率仅为5.8%,漏检率仅为9%,处理1天数据平均耗时是2.72 s,显著优于现有的最优识别模型.这表明,ADM-Pc1模型在识别效果和计算速度方面均能更好地满足实际工程需求.