Authors: Chen Haisi, Huang Jinhai, Gao Rongrong, Ye Junming, Chen Min, Wang Qinmei
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Objective
To assess the applying value of Chinese shorter version of the Visual Function Index questionnaire (VF-11R-CN) for presenting low-vision cataract pre-operation and post-operation by using minimal clinically important difference (MCID) determined by combination of distribution-based with anchor-based methods, and to compare the improvement rate of vision-related quality of life (VRQol).
Methods
A cross-sectional study was performed in this study.Ninety-eight patients with presenting low vision cataract were enrolled at Eye Hospital of Wenzhou Medical University from May 2018 to June 2019.All the patients received a phacoemulsification with intraocular lens implantation.A questionnaire survey was carried out with VF-11R-CN Scale before surgery and 1 month-3 months after surgery, and a complement anchor item was added during the questionnaire after surgery.The applicability of the scale was assessed by floor or ceiling effects, and score difference of the VF-11R-CN over time and effective size was determined.Distribution-based MCID was calculated using 0.5 standard deviation (SD) of score difference and 1.96 standard error of measurement (SEM). Anchor-based MCID was calculated using the slope of the linear regression analysis.In responder analysis, sensitivity and specificity of MCID was reported.The differences of postoperative VRQol improvement rate based-on MCID were compared between male and female, single eye disease and multiple eye diseases, pre-operative and post-operative scores.This study protocol was approved by the Ethics Committee of Eye Hospital of Wenzhou Medical University, and followed the Declaration of Helsinki.Written informed consent was obtained from each patient prior to any medical examination.
Results
A total of 85 patients completed the following up.The mean score difference was 399.51±234.92, and that of the presenting visual acuity (PVA) was 0.65±0.36.Both the minor floor and ceiling effects were 1.18% before surgery, and the ceiling effects were 22.35% after surgery.The score before surgery was significantly higher than that after surgery (t=15.68, P<0.001). The effective size for the surgery was 1.63.The MCID was 122.23 and 123.10 according to 0.5 SD and 1.96 SEM.The linearity regression analysis showed that score difference reduced 106.17 if anchor item option increased 1.The average MCID estimate was 117.17.A total of 76 patients (89.41%) reported an improvement of VRQol.The sensitivity of MCID for the assessment of VRQol was 96.67% and specificity was 46.67%.No significant differences were found in VRQol improvement rate between gender, single cataract and multiple eye diseases or PVA (LogMAR 1.3 as cutoff value) (P=0.73, 0.88, 0.27).
Conclusions
VF-11R-CN scale is available for Chinese presenting low vision cataract patients undergoing surgery.The MCID value for the cataract surgery is 117.17 scores, with a high sensitivity and a relatively low specificity.