This cross-sectional-analytical study was performed in Khatam Al-Anbia hospital in Mashhad, Iran, during 2017-2018. Having explained the objectives of the study, participants’ approval was obtained to attend in the study and complete the questionnaire.
This study was done on visually healthy individuals as a control group and patients with glaucoma and cataracts as patients group. According to the data represented in Hatt article (9) with a confidence interval of 95% and a test power of 80%, 163 adult patients participated in this study as a sample group. The first group included 163 patients who were diagnosed with glaucoma and cataracts. The diagnoses were made by an expert glaucoma surgeon. The second group included visually healthy individuals who did not have any ocular, mental and musculoskeletal diseases; and any type of refractive error. This group was selected from the companion of patients group who had recently undergone ophthalmological examinations. The sampling was done randomly. The study was performed in accordance with the tenets of the Declaration of Helsinki and as approved by the ethics committee of Mashhad University of Medical Sciences .The aim of the study was explained to the patients and their parents, and then the consent forms were obtained.
The diagnosis of cataract and glaucoma was performed based on criteria that were reported in previously published articles. (10, 11) The questionnaire was the Persian version NEI-VFQ (EuroQol five-dimensional [EQ-5D] and 39-item visual functioning questionnaire structure [NEI-VFQ 39]). EQ-5D questionnaire measures the ability of individuals to perform tasks in 5 dimensions of mobility, personal care, normal activities (such as working, studying, doing household chores, having family or leisure activities), pain (discomfort) and anxiety (depression). This questionnaire is concise but comprehensive and takes 1 to 5 minutes to be answered depending on the situation. Then each health condition on a scale of 0 to 1 was evaluated. NEI-VFQ 39 QOL is one of the most common questionnaires to measure the QOL and measures various aspects of life, including general health, visual health, mental health, eye pain, distance & near vision activities, social performance, peripheral vision, color vision, limitation of doing an activity, driving, and dependency. According to the questionnaire instruction, each question’s answer was converted into a score between 0 and 100, in which 0 indicates the worst and 100 the best score and performance. (12)
These questionnaires have been translated into the Persian language and their validity and reliability have been confirmed. (8, 9, 13) However, the questionnaires’ reliability (EQ-5D and NEI-VFQ 39) was evaluated using Cronbach’s alpha test at a confidence level of 0.95 in SPSS software.
The interview format of the questionnaire was used to determine the QOL score. In addition to completing the questionnaire, demographic information affecting the QOL of patients (including age, sex and education) was also obtained. Finally, the QOL score of patients suffering from glaucoma with cataracts during pre and post-operation phases in comparison to healthy individuals was assessed, and the factors affecting the QOL score were evaluated.
SPSS-24 (IBM Corp, Armonk, New York, USA) software was used for data analysis. For evaluating the normality of the data, which is a prerequisite of using analysis of variance, the Kolmograph-Smiranov test was used. For showing the QOL data the mean with confidence interval and for investigating and evaluating the difference in the QOL during pre and post-operation phases, one-way analysis of variance was used at a confidence level of 0.95. P-value less than 0.05 was considered as significant level. Cronbach’s alpha test was used to examine the validity of the questionnaire used according to their main variables.