The present study examined anxiety and depression in Chinese glaucoma patients and investigated the factors influencing these two psychological disorders. The most important finding of the study was that patients’ self-reported VR-QoL other than objective visual function indices, such as MD and BCVA, played the most important deciding role in psychiatric illnesses.
The prevalence of anxiety and depression in glaucoma patients in our study was 12.11% and 25.78%, respectively, which was significantly higher than that of the general normal Chinese population (2.4% and 1.4% for anxiety and depression, respectively). It was consistent with previous studies [9, 12, 13], indicating that glaucoma is a predictor of psychological disturbances. The prevalence of anxiety in glaucoma patients in our study was significantly lower than that in Singapore (64%) [14] and was similar to that in Turkey (13.5%) [7] and Japan (13%) [9]. The prevalence of depression in our study was lower than that in Turkey (57%) [7] and Singapore (30%) [14], but was higher than that in Australia (19.09%) [15], Hungary (12.1%) [16] and America (10.9%) [13].
Univariate analysis showed that age had a positive correlation with each of the anxiety and depression in glaucoma patients. The relationships between age and anxiety were controversial. Zhang et al reported that the likelihood of having anxiety along with glaucoma did not change with age [17]. However, other studies revealed that age negatively correlated with anxiety [2, 3]. The reasons of the inconsistency could be due to the differences in races, age ranges and numbers of glaucoma patients. In terms of depression, our findings was consistent with previous studies [3, 15], which showed that older age was a risk factor for depression. Our results confirmed this finding in a larger range of ages (ranging from 18 to 91 years) in glaucoma patients.
Educational level was another demographic factor that reached statistical significance with both of anxiety and depression. The results implied that increased educational level was along with decreased anxiety and depression symptoms. Living with family related to a decreased anxiety status. In addition, smaller C/D of both eyes was positively associated with anxiety, indicating that worse situation of the better eye signified a more serious anxiety status. A single marital status, long glaucoma course, POAG type, less numbers of glaucoma medications and no history of surgery treatment were related to a low degree of depression. Besides, higher IOP of both eyes was positively correlated with depression.
Multivariate linear regression analysis revealed that the composite score of NEI VFQ-25 and most of the 12 subscales were significantly negatively correlated with each of anxiety and depression disorders after adjusting for socio-demographic and clinical variables. However, for visual function indices, only BCVA of the better- and worse- seeing eyes was significantly related to anxiety after adjustment for other variables and the composite score of VR-QoL. Standardized partial regression analysis further showed that the composite score of NEI VFQ-25 accounted the most important part in each of the HADS-A and HADS-D with statistical significance.
Glaucoma is characterized by progressive optic neuropathy that could lead to visual function damage including VF defects and VA decrease [18]. Ophthalmologists paid close attention to these objective visual function indices in clinical practice. However, our results indicated that patients’ self-reported QoL but not visual function components played the most important role in psychological distresses.
Reports about the associations between self-reported measures, objective visual function indices and anxiety in eye diseases were very little. Zhou et al found that worse self-reported visual function assessed by Glaucoma Quality of Life-15 questionnaire (GQL-15) was consistently correlated with decreased anxiety and depression in glaucoma patients [2]. In retinitis pigmentosa patients, the degree of anxiety was significantly correlated with the general health and role difficulties of the NEI VFQ-25 dimensions but not with any objective visual functions, such as BCVA of better- and worse- seeing eyes [19]. With regard to depression, our results were consistent with several previous studies. Skalicky et al reported that the total score of GQL-15 was an independent predictor of depression [15]. Jampel et al studied depression and mood indicators in newly diagnosed POAG patients. In compliance with our results, they found that poorer visual function, such as worse VA and more damaged VF, were not correlated with depression symptoms and altered mood. However, patients’ perception of their vision in daily-life activities was associated with depression significantly [20]. In a nationally representative glaucoma population, Wang et al observed that several self-reported measures of visual function including NEI VFQ-25 and how much time patients spent worrying about eyesight were significantly associated with depression. Objective measures of glaucoma severity, such as BCVA, MD and C/D, were not predictors of depression [13]. Wilson et al also found that severity of VA and VF were not predictors of depression [21].
To our knowledge, this is an initial Chinese study to find that VR-QoL measured by NEI VFQ-25 was most informative in identifying patients with high risk to suffer from psychological disorders. According to our results, glaucoma patients with reduced VR-QoL are vulnerable to develop anxiety and depression problems. On contrary, patients with good results of objective visual function measures, such as MD and BCVA, do not mean they have a healthy psychological status. Hence, patients with lower VR-QoL but not with lower objective visual function performances should be assessed for potential psychological disorders. Psychological interventions from psychiatrists are needed for glaucoma patients with severe psychological burdens if necessary. For ophthalmologists, except treating patients positively to save their objective visual functions, educating them an overall and detailed knowledge about glaucoma is essential and beneficial. For example, telling patients the slow progression nature of glaucoma and effectiveness in treatments on preventing glaucoma deterioration could alleviate their psychological abnormalities. Our previous study also confirmed that the level on understanding about glaucoma is an independent factor negatively associated with anxiety and depression while positively associated with patients’ VR-QoL [22].
This study has several limitations. First, selection bias may be caused because the participants were recruited from a single tertiary institution. Second, even though the HADS questionnaire is common used for study purpose, it could not represent a formal psychological diagnosis of anxiety and depression. In addition, the cross-sectional design of the study made it unable to establish causality. Prospective studies will be needed to further confirm the conclusions.