Authors: Gao Rongrong, Guo Yan, Chen Haisi, Zhang Sifang, Wang Qinmei, Yu Ayong, Huang Jinhai
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Background
Cataract is the main cause of blindness in the world.The comprehensive evaluation of the visual function of the patients with cataract should be combined with clinical examination results and subjective evaluation.Visual function index-14 (VF-14) is an assessment tool for the cataract patients in developed countries.
Objective
This study was to develop a Chinese version visual function index-14 (VF-12-CN) and assess its application value in the evaluation of cataract patients, quality of life (QoL) and the affecting factors.
Methods
A prospective cross-sectional investigation was carried out.The VF-14 was revised and developed into a VF-12-CN by translating, back-translating and cultural adaptating.The QoL questionnaires of VF-12-CN were given to 215 patients with age-related cataract or daibetic cataract who were going to receive cataract surgery in Eye Hospital of Wenzhou Medical University from February to October, 2013.Psychometric properties of the VF-12-CN, including item difficulty and discrimination, Cronbach’s α coefficient, Split-Half reliability, intra-investigators reliability, content validity, and construct validity were tested, and the influence factors of the final questionnaire were analysised.Forty-eight patients who finished questionnaires were scored by 2 invistigators separately.Level 4 score method was used to assess whether VF-12-CN could reflect the psychometric properties of cataract.The Ethics Committee of the Eye Hospital of Wenzhou Medical University approved the study.
Results
Total 200 questionnaires were taken back with the response rate of 93.02%.Three items which involved filling of form, physical training and recreational activities were revised based on Chinese culture and life style, and 2 items that related with driving were deleted from VF-14 due to a lower response rate.The VF-12-CN showed an excellent item discrimination, with the Cronbach’s α coefficient of 0.863, Split-Half reliability of 0.874, intra-investigators reliability of 0.958 and I-CVI, S-CVI/UA, and S-CVI/Ave of 1.0.Two common factors were extracted by the factor analysis, with a cumulative variance contribution rate of 59.3%.The scale scores were positively correlated with age, uncorrected distant visual acuity (UCDVA) of better eyes and UCDVA of worse eyes(r=0.277, 0.534, 0.367, all at P<0.01). The scores were 12.5±8.6 in the illiteracy group and 15.7±7.4 in the non illiteracy group, showing an evidently difference between them (t=2.798, P<0.01), and significant differences also were found between different ages, UCDVA of better eyes, UCDVA of worse eyes or the number of cataract eyes (all at P<0.05). No significant differences were seen between gender, with and without ocular or systematic concomitant disease (t=-0.426, 0.304, -1.019, all at P>0.05). The main factors affecting the QoL of cataract patients included UCDVA of better eyes, educational degree and age, with the regression equation: scores=25.045-10.927×UCDVA of better eyes-3.342×education+ 3.201×age (R=0.586, R2=0.334, F=34.247, P=0.000).
Conclusions
VF-12-CN is a reliable and valid tool for assessing the visual functions of Chinese cataract patients.The UCDVA of better eyes is the main factor affecting QoL in cataract patients.