To our knowledge, this is the first study comparing quality of life before and after cataract surgery inTibetan popolation. We found that NEIVFQ-25 scores for cataract patients were significant improvement after cataract surgery. Others also found the same results that cataract surgery could significant improve quality of life in Japan and the USA population[17, 18].
In general, NEIVFQ-25 is suitable for assessing the vision-related quality of life of cataract patients in China. Many questionnaires have been designed to measure quality-of-life in cataract patients,such as VF-14,15-dimension generic instrument. However, these questionnaires do not focus on social functioning, mental health in cataract patients.
One advantage of the NEI VFQ-25 questionnaire is that it can measure the effects of visual impairments on mental health,role difficulties, social functioning and dependence. In addition, the Chinese version of the NEI-VFQ-25 had been verified and proposed modifications in chinese population. It removed some redundant and poor targeting questions[19–22].
However, what needs to be noticed is that NEI VFQ-25 measures the combination of visual function and social emotional structure but lacks visual function evaluation. This may reduce the effectiveness of the composite score.
As we predicted, the scores of quality of life in cataract patients were very low before surgery. The lowest item were role difficulty and mental health. It mean that cataract seriously affects the patient’s mental health.
Visual impairment affects patients 'daily activities, leading to reduced social interactions and further exacerbates patients' psychological symptoms. Fagers found that psychiatric symptoms will increase with decreased of vision, but better as vision improved . These results suggest that we should give more mental health attention to cataract patients.
We found that improvement in contrast sensitivity and stereopsis were related to improvement in VRQOL after cataract surgery, however, visual acuity was not association with VRQOL. We further found that VRQOL score will improve 13 points if one log unit contrast sensitivity increased after adjusting for potential confounders. Previous research come to the same conclusion [6, 7]. The reason why contrast sensitivity affects quality of life is that contrast sensitivity is needed in everyday activities. This result suggested that we need take contrast sensitivity and stereopsis into account when assess the impairment caused by cataract.
We also found that the improvement in stereopsis was significantly associated with improved VRQOL after cataract surgery. However, previous studies rarely measured stereopsis when investigating the effects of cataract surgery on VRQOL. More and more research found that stereopsis is significantly associated with improvements in VRQOL.
A UK study found that the most strongly association with changes in VRQOL after surgery was stereopsis. Previous studies examining the impact of cataract surgery on VRQOL have seldom measured stereopsis, which was significantly associated with improved VRQOL. The studies from Spain and Denmark also found the same results.The specific mechanism by which stereopsis affects quality of life is still unclear, we need to study further.
The advantages of this article was that it is the first to assess cataract surgery on VRQOL in Tibetan population. Tibet is one of most poor area in China. Previous studies have seldom included rural inhabitants, and more than 93% of patients in this study were rural residents. It is important to concern the impacted of cataract surgery on VRQOL in poor areas. Another advantage of this study is using GEE linear regression model to eliminate other factors which may affect the vision-related quality of life, such as co-morbidities including and medication usage.