Reliability and reproducibility of a Chinese-language visual function assessment.
OBJECTIVE: The purpose of the study was to validate a Chinese-language visual function assessment within the context of a routine cataract surgery practice and to assess the contribution of the method of questionnaire administration. DESIGN: The visual function assessment (VFA) was translated into Chinese. Two groups of study subjects were recruited: Chinese who did not speak English and Chinese conversant in English. Consecutive preoperative cataract patients of Chinese ancestry presenting to an urban ophthalmology practice were recruited. The questionnaire was administered in person or by telephone interview. Pre-operative visual acuity was recorded. Visual function scores were analyzed to assess reliability and correlation with visual acuity. RESULTS: Among the 186 potential study subjects, 155 patients completed the study The Chinese-language visual function assessment had good internal consistency (Cronbach alpha = 0.97, inter-item correlations = 0.43 to 0.96) . Reliability (with regard to the English version) and test-retest reproducibility of the Chinese questionnaire were strong with intraclass correlation coefficients greater than 0.60. The method of administration contributed to the measures of reliability and reproducibility. CONCLUSION: These results show that a Chinese-language version of the VFA questionnaire is reliable and valid. In industrialized countries with large Chinese-speaking populations and newly developed countries of East and Southeast Asia, the visual function assessment may be helpful in assisting routine clinical patient evaluation and cross-cultural outcome assessment programmes. Our findings also suggest that self-administered visual function assessments may be more reliable and valid than interview-generated assessments.