白内障患者报告结局条目库的研制

目的:基于Rasch模型研制白内障患者报告结局(PROs)条目库,为准确、全面和动态评估白内障PROs奠定基础.方法:横断面调查研究.根据纳入标准选取我院已确诊的白内障住院患者,采用本课题组前期基于循证医学方法构建的白内障PROs条目池对其进行问卷调查.通过Rasch分析各维度条目选项概率曲线(CPC)、测量精密性、条目拟合指标(infit/outfit MNSQ)、单维性、匹配度和条目功能差异(DIF)等测量特性指标,并反复迭代、提炼,直至得到测量特性优良的条目.采用Pearson相关分析评估各维度和视力的相关性.结果:共纳入296例白内障患者,其中男130例,女166例,年龄70(63,77)岁,受过小学及以上教育者178例(60.1%),术前双眼日常生活视力(LogMAR)为0.0~3.0,中位数为0.6.条目库共纳入3个维度,其中视觉相关活动受限维度23个条目,视觉症状维度14个条目,精神心理健康11个条目,所有条目选项数量均为4个.视觉相关活动受限维度中,选项类别阈值分别为-1.84、0.04、1.79,被试分离信度/被试分离系数(PSR/PSI)为0.93/3.59,主成分分析(PCA)第一成分未解释方差特征值为2.61,匹配度为-0.81,DIF值均小于1;该维度得分与好眼视力(r=0.619,P<0.01)和双眼视力(r=0.622,P<0.01)有相关性.视觉症状维度中,选项类别阈值分别为-1.83、-0.18、2.00,PSR/PSI为0.88/2.68,PCA第一成分未解释方差特征值为2.53,匹配度为-1.35,2个条目在眼部并发症方面的DIF值大于1,其余DIF值均小于1;该维度得分与好眼视力(r=0.482,P<0.01)和双眼视力(r=0.492,P<0.01)有相关性.精神心理健康维度中,选项类别阈值分别为-2.83、0.03、2.80,PSR/PSI为0.88/2.68,PCA第一成分未解释方差特征值为2.79,匹配度为-0.34,所有条目DIF值均小于1;该维度得分与好眼视力(r=0.425,P<0.01)和双眼视力(r=0.426,P<0.01)有相关性.上述所有条目infit和outfit值均介于0.50~1.50之间.结论:基于Rasch分析研制的白内障PROs条目库覆盖了视觉相关活动受限、视觉症状和精神心理健康3个方面,全面地反应了白内障PROs的内涵,且条目简明易懂,临床可操作性好,具有较好的测量特性.     

中文版儿童间歇性外斜视生存质量量表的Rasch分析

目的通过Rasch分析提炼和优化中文版儿童间歇性外斜视量表（CIXTQs）,以更好地评估中国间歇性外斜视儿童和家长的生存质量状况。方法横断面研究。在2016年6-8月期间收集5~17岁间歇性外斜视儿童青少年211例,平均年龄（9.7±3.0）岁。其中5~7岁54例,8~17岁157例。分别按要求对儿童和家长采用CIXTQs进行调查,分为5~7岁儿童、8~17岁儿童、家长代理和家长问卷4个量表。根据每一量表的每一条目得分情况使用Winsteps 3.72.3软件的等级模式进行Rasch分析,分析条目及答案的心理计量特征。各量表分析的项目包括分解维度、选项排序、局部独立性、适合度分析、项目适中性分析、最终确定维度等。结果选项排序发现5~17岁儿童青少年量表的选项均为3个,分别是“从来没有”、“有时”、“总是”,家长代理量表和家长问卷量表保留的选项排序和原量表相同,为5个。家长问卷量表仍保留3个维度,分别为功能维度、社会心理维度和手术维度;项目适合度分析发现需要删减家长问卷量表的功能维度中的条目1,社会心理维度中的条目5;删减条目后发现家长问卷量表中的手术维度的个体分离指数较差（＜1.5）。项目适中性分析发现各量表项目难度和研究对象个体能力之间的匹配情况均很好。结论提炼和优化后的CIXTQs将能更明确地反映间歇性外斜视对儿童青少年及其家长生存质量影响的因素,更敏感地评估间歇性外斜视儿童及其家长的生存质量状况。     

后囊环形切除及其联合前段玻璃体切除术对后发性白内障影响的Meta分析

目的 系统评价白内障超声乳化吸除术中选择Ⅰ期后囊环形切除（PCCC）与选择Ⅰ期后囊环形切除联合前段玻璃体切除（PCCC＋AV）对患者后发性白内障的影响。设计 基于文献检索的Meta分析。研究对象 检索MEDLINE数据库、中国期刊网专题全文数据库、中文生物医学文献数据库、维普中文科技期刊数据库、中国医学学术会议论文、中国优秀硕博士论文数据库、超星数字图书馆、书生之家数字图书馆等；手工检索国内外相关教科书、会议论文等；并以所有检出文献的参考文献作为补充。方法 严格按照纳入、排除标准筛选文献，并对纳入文献进行质量评估，提取研究所需信息。数据分析选用Review Manager 4．2．2软件、SPSS10．0软件，检验异质性，根据检验结果选择相应的效应模型进行Meta分析，以优势比（OR）判定PCCC术式和PCCC＋AV术式对患者后发性白内障的影响，并改变选择的效应模型，计算失效安全数（Nfs）进行敏感性分析。主要指标 纳入研究的文献异质性，研究结果的敏感性，95％置信区间（CI）及Nfs。结果 6篇文献共计305例白内障患者。经异质性检验，纳入文献无异质性，选择固定效应模型计算OR值。后发性白内障PCCC组与PCCC＋AV组的合并OR值为0．13（95％CI：0．06～0．25），差异有统计学意义（P〈0．000）。改用随机效应模型计算OR值，进行敏感性分析，差异仍有统计学意义（P〈0．000），且Nfs=76．8，纳入文献稳定性好。结论 白内障超声乳化吸除术中选择Ⅰ期PCCC＋AV术式患者较术中单纯选择I期PCCC术式的患者更能有效抑制后发性白内障的发生。     

中文版低视力者生活质量量表的 Rasch分析

目的：通过Rasch分析评估中文版低视力者生活质量量表（CLVQOL）,优化提炼该量表。方法：回顾 性系列病例研究。收集2017年1-12月在温州医科大学附属眼视光医院低视力门诊就诊的低视力患 者189例,对其进行CLVQOL问卷调查。患者的年龄为（40.9±20.2）岁,男/女比例为1.6∶1。根据 每一量表的每一条目得分情况使用Winsteps 3.72.2软件的等级模式进行Rasch分析,分析条目及答案 的心理计量特征。分析的项目内容分别为：分解维度、选项排序、局部独立性、适合度分析、项目 差别功能和项目适中性分析。结果：CLVQOL由4个维度组成。各维度选项之间存在互相包含现象, 且第一特征根均在2左右,单维性检验尚在可接受范围内。选项排序发现选项2和4与其相邻选项分 离不够清晰。同一维度内条目间具有较好的独立性。第四维度Q24的适合均方为1.55,不适合均方 为1.58,超过了0.60～1.40的标准范围。按性别分析4个维度的项目功能差异,Q24在性别间差异大 于5。项目与个体匹配不是很好,除了第三维度项目平均分高于个体平均得分外,其他维度项目平 均得分均低于个体平均得分。同时,各维度对个体的测量信息也较低。结论：CLVQOL具有良好的 信效度,通过Rasch分析表明其量表选项应根据我国社会经济背景及低视力人群生活需求进行重新 设计优化,使量表更适用于中国低视力人群。     

白内障术前眼球生物学参数测量和应用专家共识(2023)

白内障是全球主要的可治疗性致盲眼病, 目前手术摘除混浊晶状体并植入人工晶状体(IOL)是治疗白内障的主要方法, IOL屈光力的准确计算是提高术眼术后视觉质量的关键, 其计算涉及术眼术前眼球生物学参数的准确测量。白内障术前应重点关注眼球生物学参数的测量和应用, 主要包括精准的眼球生物学参数测量设备的选择和IOL屈光力计算公式的选择等。为了更好地满足术眼术后视觉质量和生活质量的需求, 本专家共识依据国际上的重要文献和循证证据对白内障术前眼球生物学测量参数的选择和测量方法提出推荐意见, 既包括传统的眼轴长度、角膜曲率、前房深度、晶状体厚度、角膜直径及中央角膜厚度等眼球结构参数, 还纳入了Kappa角、Alpha角及波前像差等视光学参数。本共识同时还推荐了IOL屈光力计算公式需要的参数, 旨在规范临床医生对白内障患者实施白内障手术术前眼球生物学测量参数的选择、测量和应用, 从而提高白内障手术后的屈光效果和视觉质量。     

Catquest 9SF-CN量表在白内障中的最小临床重要差异研究

目的：评估Catquest 9SF -CN量表应用于白内障手术人群的反应度，并结合校标法和分布法确定最小临床重要差异值（MCID）。方法：前瞻性队列研究。对纳入温州医科大学附属眼视光医院的213例白内障术前患者进行Catquest 9SF -CN量表调查。术后1～3个月对来院复查的患者再次进行量表调查和7个选项的校标条目调查。分析量表的天花板和地板效应，通过配对t检验分析手术前后量表得分和视力的差异，采用效应值、标准化反应均数和变化率三个指标联合评估量表的反应度。然后根据术前视力、术前并发症（有/无）和术眼数量（单眼/双眼）分组，计算手术带来的得分变化。通过单因素方差分析（根据术前视力分组）或独立样本t检验（根据并发症或者术眼数量分组）分析组间差异。分布法通过1个效应值、1个测量标准误和1/2个得分变化标准差估算MCID，校标法通过校标选项和得分变化的线性回归分析估算MCID，最后根据平均值法确定取值。结果：共144人完成Catquest 9SF -CN量表的随访调查。量表术前的天花板和地板效应为4.2%，术后提高至17.3%。手术带来的量表总得分变化为（10.4±7.7）分，logMAR视力变化为（0.3±0.3），两者有相关性（r=0.30， P<0.001），且各自手术前后的差异具有统计学意义（t视力=13.44，t得分=16.75，P<0.001）。量表的效应值、标准化反应均数和变化率分别是1.71，1.40和44.46%。有完整随访资料的患者根据术前视力分成3组，或者根据术眼数量分成2组后，组间的得分变化差异均无统计学意义。根据并发症分组后，差异有统计学意义（t=2.90，P=0.004）。分布法中1个效应值、1个测量标准误和1/2个得分变化标准差估算MCID分别为1.71分，2.12分和3.96分。校标法中量表得分变化和校标条目选项存在显著相关（r=-0.35，P<0.001），回归公式中的β系数为3.74，用来估计MCID值。结合分布法和校标法取平均值得到最终MCID值2.88分。结论：Catquest 9SF-CN量表适用于白内障生活质量评估，在中国白内障手术前后的反应度良好，并建立了MCID值2.88分作为应用参考。     

翼状胬肉治疗中应用贝伐单抗的疗效的Meta分析

目的 探讨贝伐单抗（bevacizumab）在翼状胬肉治疗中的临床疗效。设计 Meta分析。研究对象 国内外于从2001年1月1日至2014年9月30日发表的以翼状胬肉患者作为研究对象,治疗方案采用贝伐单抗与对照组相比的随机对照试验。方法 应用循证医学的研究方法检索美国国立医学图书馆、荷兰医学文摘、循证医学数据库、中国知网、万方数据库、中国期刊全文数据库及维普中文科技期刊数据库并辅以手工检索,遵循Cochrane Handbook 5.0偏倚风险评估工具评价纳入研究的质量,采用RevMan 5.0和SPSS 10.0软件进行统计学处理。主要指标 贝伐单抗用于翼状胬肉的复发率和并发症的比值比（OR）。结果 纳入7项随机对照试验,共398眼。分析结果显示：与空白对照组相比,贝伐单抗组在防止胬肉复发方面,差异无统计学意义[OR=0.60,95%CI(0.34~1.05),P=0.07,I2=7%];在术后并发症方面,两组比较差异无统计学意义[OR=0.68,95％CI (0.38~1.22),P=0.19, I2=0%]。结论 在翼状胬肉治疗中,应用贝伐单抗不能降低复发率。     

双眼先天性白内障儿童生活质量量表的制订及评价

目的制订8～15岁双眼先天性白内障儿童生活质量量表,评价量表的效度、信度以及反应度。方法根据儿童生活质量的定义设计,涵盖与视功能损害有关的重要指标,编制23个条目的双眼先天性白内障儿童生活质量量表。应用该量表对8～15岁的18例正常视力儿童和76例双眼先天性白内障儿童进行了量表调查。应用离散程度法、相关系数法、因子分析法、区分度分析法、克朗巴赫系数法和重测信度法来筛选量表有效条目,并评价筛选后量表的效度、信度以及反应度。结果条目5、7和21经筛选后删除,形成20个条目的量表。每个条目和每个分项的内容效度相关系数均大于0．6（P〈0．05）。正常儿童和白内障儿童、白内障儿童术前和术后总得分间的差异均有统计学意义（P=0．000）。重测信度的相关系数为0．895（P=0．000）。本量表4个分项的克朗巴赫a信度系数值分别为0．822、0．922、0．797和0．794。效应尺度统计量为1．141。结论经筛选后的20个条目的量表符合生活质量量表效度、信度以及反应度的技术要求,可以应用于8～15岁的双眼先天性白内障儿童生活质量的临床研究。     

高阶像差对人工晶状体眼视觉质量的影响

目的 观察高阶像差对超声乳化并人工晶状体植入术后眼视觉质量的影响,探讨改善术后视觉质量的方法.方法 检测129例（129眼）白内障超乳并人工晶状体植入术后眼总高阶像差、球差（Z400）、彗差（Z310、311）等各高阶像差均方根值（RMS）,并用问卷调查表进行视觉质量评分,行Pearson相关分析检验.结果 所用问卷调查表的信度较高,重复测量效果良好;球差（Z400）、二级散光（Z420）、总高阶像差与术后患者的主观视觉质量之间存在较强的关联,相关性具有统计学意义（P＜0.05）.结论 白内障超乳并人工晶状体植入术后,眼高阶阶像差会影响术后患者的主观视觉质量,尤其是总高阶像差、球差,二级散光.     

波前像差测量技术在白内障手术方面的应用意义（综述）

波阵面像差（wavefront aberration）（亦有学者称波前像差）是近年来眼科研究的一个热点。波前像差测量技术可应用于白内障术后患者视觉质量的评价以及非球面人工晶状体的个性化选择。本文就波前像差的概念及波前像差测量技术在白内障手术后视觉质量的评价及非球面人工晶状体个性化选择中的应用进展做一简要综述。     

国人版角膜接触镜配戴者生活质量量表的研制与评估

目的：研制国人版角膜接触镜配戴者生活质量量表（CLIQ）并评估其信度和效度,分析得分的影响因素。方法：对英国原版CLIQ进行翻译、回译、文化调试,形成国人版量表。采用横断面研究,选择2015年4─12月在温州医科大学附属眼视光医院就诊的角膜接触镜配戴者205例进行问卷调查, 其中再随机选取20例由2名调查员分别进行调查,对问卷数据进行统计分析。结果：回收有效问卷201例。视功能维度因应答率小于50%被删除。量表Cronbach's α系数为0.77,眼部症状维度为0.68, 便利性、经济和情感维度均>0.7,量表Guttmann Split-Half系数为0.89,眼部症状、便利性、经济和情感维度分别为0.75、0.78、0.65和0.93。认知维度Cronbach's α系数和Guttmann Split-Half系数均为 0.49故被删除;删除条目20后健康关注维度Cronbach's α系数和Guttmann Split-Half系数分别为0.68 和0.73。2名调查员之间的评分结果高度相关（r=0.87～0.99,P<0.001）。各条目的条目水平内容效度指数为0.83～1.00,量表的平均水平内容效度指数为0.95。探索性因子分析提取的5个因子分别对应各维度,累计方差贡献率60.43%。眼部症状维度与年龄（r=-0.153,P=0.03）和戴镜年数（r=-0.167, P=0.018）轻度相关,情感维度与戴镜年数轻度相关（r=0.209,P=0.003）。量表总分在不同戴镜年数[（3.60±0.34）年 vs. （3.71±0.32）年,P=0.026、每月戴镜天数[（3.60±0.33）d vs. （3.70±0.33）d, P=0.041]和无/有眼部症状（3.71±0.32 vs. 3.60±0.34,P=0.021）的配戴者间差异有统计学意义。软镜配戴者的经济维度对分高于硬镜配戴者（t=2.588,P=0.017）。结论：删去视功能维度、认知维度和条目20后,CLIQ量表的信度和效度较好,戴镜年数越长、每月戴镜天数越多以及无眼部症状的患者得分较高,硬镜配戴者在花费方面的担忧更多。     

Development and validation of a multidimensional quality-of-life scale for myopia.

BACKGROUND: Five dimensions of health-related quality of life in myopia were hypothesized to affect satisfaction with visual correction modality. Items on these dimensions reflected the frequency of visual compromise and ocular symptoms; individual tolerance of these compromises and symptoms; cosmesis; psychological constructs (including situation-dependent characteristics such as adaptability, self-efficacy, and subjective well-being); and personality traits such as extraversion and introversion. METHODS: Psychologically oriented items and visually oriented items were developed in two stages involving 1,647 participants. Item development was based on a comprehensive literature review, interviews with experts, myopic subjects, and graduate students, and written feedback. Items were selected through factor analysis and the examination of their ability to discriminate between treatment conditions (spectacle wear, daily use of contact lenses, continuous use of contact lenses, or laser-assisted in-situ keratomileusis for myopia). After development, selection, and validation of the psychological items and then the vision items, a final multidimensional scale combining both types of items was designed. The scale was administered to 124 subjects whose myopia was corrected by one of several treatment modalities to determine final construct validity. RESULTS: Using principal axis factoring and oblimin with Kaiser normalization rotation methods, five factors with strong item loadings evolved as hypothesized. The final multidimensional scale consisted of 13 items related to specific aspects of frequency of visual compromise and ocular symptoms with 13 corresponding items for level of tolerance for these problems; three items related to cosmesis; 10 items related to psychological characteristics; and six items related to personality traits. Good internal consistency in each factor (Cronbach's alpha range, 0.76 to 0.92) for the scale was evident. DISCUSSION: This report describes the development and validation of an easily administered, short, effective multidimensional health-related quality-of-life questionnaire for use in selecting and measuring success of methods for correcting myopia.     

Description and measurement of handicap caused by vision impairment.

To develop an instrument to describe and quantify handicap caused by vision impairment an item pool was derived from focus groups and from a review of vision-related quality-of-life questionnaires. Only items related to handicap were included and grouped into five subscales. The 76-item 'Impact of Vision Impairment' was administered to 95 people who were vision impaired. Content validity was established by consultation with professionals and with people with impaired vision. Forty-six items remained after the elimination of those found to be irrelevant and others with inter-item correlation coefficients of > or = 0.7. Univariate and multivariate analyses revealed an association between visual acuity and type and degree of handicap on subscales, except emotional reaction to vision loss, which is related to cause of vision impairment. The instrument is responsive to the level of vision loss and discriminates the different performances of people with different causes of vision loss.     

Development of a questionnaire for measurement of vision-related quality of life

PURPOSE. To define vision-related quality of life, to outline the development of a vision-specific quality of life instrument and to present the characteristics of a 10-item `core' questionnaire. METHOD. A standard method included: 1. Generation of relevant issues by individual interviews with 38 visually impaired adults, consultation with 37 professionals and support workers and literature review. 2. Operationalisation, involving 58 ophthalmic patients. 3. Pre-testing, to maximise face validity and content validity, involving 184 individuals with a variety of different visual problems and social backgrounds. 4. Adoption of a modular approach to item selection. 5. Formal piloting in 92 individuals to establish reliability and construct validity. RESULTS. More than 232 items were tested of which 139 were considered suitable for a final question pool or `parent' questionnaire (the VQOL). From this parent questionnaire individual items or groups of items can be selected. Ten broadly applicable items referring to physical, social and psychological issues were selected for the core questionnaire (the VCM1). The VCM1 has high reliability (alpha = 0.93) and validity. CONCLUSIONS. Any self-reported problem relating to vision may constitute a quality of life issue. A modular approach to item selection may provide the flexibility to investigate vision-related quality of life in a wide range of clinical settings, allowing detailed assessment of specific problems and also cross-study comparisons where appropriate.     

Further validation of the Daily Living Tasks Dependent on Vision: identification of domains

AIM: To examine the Daily Living Tasks Dependent on Vision (DLTV), a visual function questionnaire for domain structure, and redundancy. METHOD: 235 subjects underwent full ophthalmic assessment and completed the DLTV questionnaire by interview. Principal component analysis with varimax rotation and item response theory (IRT) were used to assign the items to domains. The internal consistency of each domain was examined using Cronbach's alpha. Redundancy was assessed by regressing each item in a domain against the remainder of items in that domain. RESULTS: Four domains were identified. Domain 1 was formed by nine items, which after applying IRT were seen to be among the most difficult questions in the instrument. Domain 2 contained eight items, all of which fell in the easier half of the instrument on applying IRT. Domain 3 contained only three items, all of which were among the easier questions and appear to deal with peripheral vision function. Domain 4 consisted of two items dealing with adaptation to light and dark conditions. Cronbach's alpha for each domain was 0.96, 0.93, 0.73, 0.66. Redundancy was found to be present in domain 1, which was therefore reduced by two items, with little effect on internal consistency. CONCLUSIONS: The authors believe using the domains identified in this report will optimise the information provided by patients on their ability to function on visually demanding tasks.     

Are standard instruments valid for the assessment of quality of life and symptoms in glaucoma?

PURPOSE: To determine if the impact of Visual Impairment Instrument (IVI) and Glaucoma Symptom Scale (GSS) are valid instruments to assess participation in daily living and ophthalmic complaints, respectively, in a glaucoma population. METHODS: Patients with glaucoma were recruited from private and public clinics and completed the IVI and GSS questionnaires. The two scales were assessed for fit to the Rasch model. Unidimensionality, individual item and person fit to the model, response category performance (how respondents differentiate between the response options), differential item functioning (how subgroups, despite equal levels of the underlying trait, respond differently to an individual item), and targeting of items to patients (good spread of items across the full range of patients' scores) were assessed. RESULTS: One hundred seventy-five participants (mean age = 71 year) were recruited. The majority (65%) had primary open angle glaucoma and good presenting visual acuity >or=6/9 in the better eye (87%). Only one-third of the participants had severe visual field loss in both eyes. Disordered thresholds were evident across all GSS items, indicating that the categories were difficult to discriminate and required category collapsing (5 to 3 categories). There was no evidence of person and item misfit, differential item functioning, and multidimensionality. However, both scales displayed ineffective person-item targeting as a large number of participants demonstrated little difficulty with the most difficult items. CONCLUSIONS: Because of unsatisfactory targeting, The IVI and GSS are suboptimal scales to assess patients with glaucoma but relatively good vision. It is likely that items could be added to optimize the performance of both instruments. There may however be a need to develop a glaucoma-specific instrument to assess Quality of Life in this population.     

Assessment of the impact of vision impairment

PURPOSE: To describe the psychometric characteristics of the Impact of Vision Impairment (IVI) Profile and evaluate its validity and reliability over time and between different forms of administration. METHODS: The IVI is a 32-item questionnaire developed to measure the impact of vision impairment on restriction of participation in daily activities in five domains of functioning. Each item is rated on a six-level scale from "no difficulty" to "can't do because of vision." The IVI was administered by trained interviewers to 115 people with impaired vision (visual acuity less than 6/12 or visual field deficit) who attended the Royal Victorian Eye and Ear Hospital, a vision rehabilitation agency, or a self-help group for people with impaired vision. Data were also collected on demographic characteristics of participants, cause of vision impairment, and distance and near vision. General health status was assessed with the Short Form-12 (SF-12) of the Physical and Mental Health Summary Scales. A subset of participants completed the IVI twice, either 1 to 2 weeks apart or by different forms of administration (different interviewers or self). RESULTS: Internal consistency of total and domain average IVI scores was high (alpha = 0.80-0.96) and sequential elimination of items did not affect consistency. Total and domain average IVI scores correlated moderately with both near and distance vision (r = 0.21-0.31) but did not correlate with physical or general health or comorbidity. Total and domain average IVI scores correlated most closely with global measures of restriction of participation (r = 0.44-0.82). Principal-components analysis confirmed that all IVI items contribute to one underlying theme and tended to confirm two of the five domains: emotional reaction to vision loss and mobility. The first three components explained 43%, 8%, and 6% of the variation in the data. Guttman split-half reliability coefficients between different forms of administration and over time ranged from 0.73 to 0.94 for domain and total IVI scores. Mean absolute difference for domain and total scores between administrations was less than 1 step for all domains and the total score. CONCLUSIONS: This study provides support that the IVI has sufficient internal and construct validity to measure the effect of vision impairment on restriction of participation in daily activities. The IVI demonstrates acceptable reliability over a short period and yields consistent results between interviewers. The IVI can also be self-administered with assurance that the results will be comparable to those that would have been obtained by a trained interviewer. Therefore, the psychometric characteristics of the IVI support its use in assessment of the vision rehabilitation needs of people with impaired vision. Its stability over time indicates that it has potential to evaluate outcomes of intervention.