Lamoureux Ecosse L, Ferraro John G, Pallant Julie F, Pesudovs Konrad, Rees Gwyn, Keeffe Jill E
Centre for Eye Research Australia, The University of Melbourne, Melbourne, Victoria, Australia.
Optom Vis Sci. 2007 Aug;84(8):789-96. doi: 10.1097/OPX.0b013e3181334b83.
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.
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.
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.
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.
确定视力损害评估工具（IVI）和青光眼症状量表（GSS）是否分别是评估青光眼患者日常生活参与度和眼科症状的有效工具。
从私立和公立诊所招募青光眼患者，并让他们完成IVI和GSS问卷。评估这两个量表与拉施模型的拟合度。评估单维性、单个项目和个体与模型的拟合度、反应类别表现（受访者如何区分反应选项）、项目功能差异（尽管潜在特征水平相同，但不同亚组对单个项目的反应如何不同）以及项目针对患者的情况（项目在患者分数的整个范围内的良好分布）。
招募了175名参与者（平均年龄 = 71岁）。大多数（65%）患有原发性开角型青光眼，较好眼的初始视力良好≥6/9（87%）。只有三分之一的参与者双眼有严重的视野缺损。所有GSS项目的阈值都存在紊乱，这表明类别难以区分，需要合并类别（从5个类别合并为3个类别）。没有证据表明个体和项目不匹配、项目功能差异和多维性。然而，两个量表都显示出个体与项目的靶向无效，因为大量参与者在最难的项目上几乎没有困难。
由于靶向不令人满意，IVI和GSS是评估青光眼但视力相对较好患者的次优量表。可能需要增加项目以优化这两种工具的性能。然而，可能需要开发一种专门针对青光眼患者的工具来评估该人群的生活质量。
