East Asian Arch Psychiatry 2015;25:115-121

ORIGINAL ARTICLE 

Dr Wei Zheng, MD, Guangzhou Brain Hospital (Guangzhou Huiai Hospital), Affiliated Hospital of Guangzhou Medical University, Guangzhou, PR China & Beijing Anding Hospital, Capital Medical University, PR China.
Dr Li-Rong Tang, MD, Beijing Anding Hospital, Capital Medical University, PR China.
Dr Christoph U. Correll, MD, Division of Psychiatry Research, The Zucker Hillside Hospital, North Shore-Long Island Jewish Health System, Glen Oaks, New York, United States.
Dr Gabor S. Ungvari, MD, PhD, University of Notre Dame Australia / Marian Centre and School of Psychiatry & Clinical Neurosciences, University of Western Australia, Perth, Australia.
Prof. Helen F. K. Chiu, FRCPsych, Department of Psychiatry, Chinese University of Hong Kong, Hong Kong SAR, PR China.
Dr Ying-Qiang Xiang, MD, PhD, Beijing Anding Hospital, Capital Medical University, PR China.
Dr Yu-Tao Xiang, MD, PhD, Unit of Psychiatry, Faculty of Health Sciences, University of Macau, Macao SAR, PR China.

Address for correspondence: Dr Yu-Tao Xiang, 3/F, Building E12, Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macao SAR, PR China.
Tel: (853) 8822 4223; Fax: (853) 2288 2314; Email: xyutly@gmail.com

Submitted: 3 February 2015; Accepted: 24 April 2015

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Introduction

Psychiatric patients have poorer physical health and less access to health care relative to the general population, and their medical conditions are frequently underdiagnosed and undertreated.¹ Psychiatric patients often neglect their medical symptoms, either because of limited financial resources to seek medical care or due to paranoid ideas.²

Ocular side-effects of psychiatric medications, such as diplopia and blurred vision, have been previously studied.³ Apart from the liver, the eye seems to be the organ most frequently affected by drug toxicity⁴ since all psychotropic medications can have ocular side-effects.³ Poor eyesight has the potential to negatively impact the patients’ social functioning and community living skills.

Few studies have examined the frequency of visual impairment in psychiatric patients. Visual impairment can arise as a result of either ocular side-effects caused by psychotropic medications or psychiatric disorders themselves. Ungvari et al5 examined 428 randomly selected hospitalised Chinese psychiatric patients and found that up to 75% had distant visual impairment (DVI); nonetheless the possible causes of DVI and its influence on patient function were not examined. In the past decades, quality of life (QoL) has been increasingly used as an outcome to evaluate the effectiveness of mental health services.6,7 We identified no study that explored the impact of visual impairment on psychiatric patients’ QoL. The present study aimed to examine the frequency of DVI in Chinese psychiatric patients and explore its demographic and clinical correlates and influence on patients’ QoL.

Methods

Study Design and Participants

The study was conducted between 1 July 2013 and 30 September 2013 at Beijing Anding Hospital, a standalone 700-bed university-affiliated psychiatric centre in Beijing, China that serves approximately 19 million people. During the study period, all consecutively admitted patients aged ≥ 18 years who were able to understand the simple instructions of the eye examination and were willing to give written informed consent were invited to participate in the study. The study protocol was approved by the Human Research and Ethics Committee of Beijing Anding Hospital.

Instruments and Assessments

Face-to-face interviews were conducted by 2 interviewers for all assessments. Basic socio-demographic and clinical characteristics were collected using a data collection form designed for the study. Data on the current use of first- and second-generation antipsychotics, psychiatric diagnoses, and major medical conditions including ocular diseases were collected from the medical records and confirmed with patients and family members where available.

Presenting monocular distant visual acuity was measured from a distance of 2.5 metres with a Logarithm of the Minimum Angle of Resolution (LogMAR) chart (Wenzhou Xingkang Medicaltech Co., Ltd., Wenzhou, Zhejiang Province, China) under standard illumination while patients were wearing their spectacles, if they had them.⁸ This method on presenting visual acuity was preferred rather than the best corrected eyesight, because the ocular vision with usual spectacle correction characterises the actual level of vision in everyday life.⁹ Visual impairment was defined as a presenting (as opposed to uncorrected) acuity binocular distant visual acuity of a LogMAR score of ≥ 0.5 that corresponds to < 6/18 Snellen acuity.^9,10 We used presenting as opposed to uncorrected visual acuity assessments in order to be able to correlate real-life visual acuity with QoL measures. Nonetheless to allow for comparison with the literature,⁵ we also calculated the frequency of uncorrected DVI in the current sample using 20/40 or worse on the Snellen Chart, the same cutoff as used by these authors.

The severity of psychotic symptoms was assessed with the Brief Psychiatric Rating Scale.^11,12 The Chinese version of the 16-item Quick Inventory of Depressive Symptomatology (Self-Report) total score measured the severity of depressive symptoms within the past week (total score range, 0-27; higher score indicates more severe depressive symptoms).^13,14 The Chinese version of the Udvalg for Kliniske Undersøgelser Side Effect Rating Scale¹⁵ was used to record drug-induced side-effects. Current smoking referred to smoking at least 1 cigarette daily during the past month.¹⁶ Current alcohol use was defined as at least 1 standard alcoholic beverage per month during the past year.¹⁷

Generic QoL was assessed with the Chinese version of the 12-item Short-Form Medical Outcomes Study (SF- 12).¹⁸ The SF-12 is a multidimensional generic instrument with 12 items addressing 2 components: physical and mental QoL. A higher score on SF-12 indicates better QoL. Vision- related QoL was measured using the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ25),¹⁹ a self-administered instrument. Its total score ranges from 0 to 100, with a higher score indicating lower QoL.

Prior to the study, the 2 interviewers (the first and second authors) underwent 3 weeks of training by an ophthalmologist on the measurement of visual acuity. They were also trained in the use of the above-mentioned assessment tools in 20 psychiatric patients. The inter-rater reliability of the rating instruments and the judgement of DVI between the raters yielded satisfactory-to-good agreement (> 0.75).

Statistical Analyses

The statistical analysis was performed using the Statistical Package for the Social Sciences version 20.0 (SPSS Inc., Chicago [IL], US). Comparisons between DVI and non-DVI patients in terms of demographic and clinical variables were made with Chi-square tests, t tests, or Mann-Whitney U tests as appropriate. Quality of life was compared between the DVI and non-DVI groups after controlling for the confounding effects of basic demographic and clinical variables that significantly differed in univariate analyses using analysis of covariance. Multiple logistic regression analysis with the “Enter” method was used to determine the demographic and clinical variables significantly associated with DVI. Due to the exploratory nature of this study, statistical significance was set at 0.05 (2-tailed).

Results

Of the 376 patients invited to participate in the study, 356 (94.7%) fulfilled the study entry criteria and completed the visual acuity test. The mean (± standard deviation) age of patients was 37.6 ± 12.6 years, with a mean illness duration of 8.8 ± 9.5 years; 43% were male (Table 1). Most patients had a primary diagnosis of schizophrenia (44%) followed by bipolar disorder (33%) and major depressive disorder (MDD) [23%]. The most frequently prescribed medication classes were antipsychotics (85%) followed by benzodiazepines (34%), mood stabilisers (29%), antidepressants (28%), and anticholinergics (22%).

Altogether, 119 (33%) patients had some form(s) of eye disease: 68 had myopia, 36 had astigmatism, 10 had presbyopia, 3 had ocular trauma, 2 had chronic conjunctivitis, and 2 had cataract; 56 (47%) of these patients wore spectacles. In total, 12.6% (n = 45) of the whole sample had DVI; the corresponding figures were 15.2% (n = 24) in schizophrenia, 11.9% (n = 14) in bipolar disorder, and 8.8% (n = 7) in MDD (Chi-square = 2.0, degrees of freedom = 2, p = 0.35). The mean logMAR scores of left and right eye were 0.16 ± 0.28 and 0.18 ± 0.28, respectively. Using the same DVI definition as that by Ungvari et al,⁵ i.e. uncorrected distant vision acuity of 20/40 or worse, with the Snellen chart the frequency of DVI rose to 35.7%.

Compared with the non-DVI group, DVI patients were more likely to have ocular disease, an obvious association (Table 1). After controlling for the confounding effect of ocular disease, DVI patients had lower QoL in the domain of general vision compared with the non-DVI group, but there was no difference in the physical and mental domains of the SF-12 and in other subscales of the NEI-VFQ25 (Table 2).

Table 3 displays the factors independently associated with DVI in logistic regression analyses. Compared with the non-DVI group, DVI patients were more likely to have ocular disease, which accounted for 12.9% of the variance of DVI (p < 0.001).

Discussion

In this study, the frequency of DVI (12.6%) was within the range reported in the Chinese general population (5.4%- 15.8%),^20,21 but significantly lower than the figure (75%) found in chronic psychiatric patients in Hong Kong.⁵ Nonetheless direct comparisons between either sample are complicated by the fact that DVI was defined differently and that frequencies of DVI vary greatly with demographic and clinical characteristics. Notably, ethnicity,²² visual test measures, and types of mental health services are relevant determinants of DVI in psychiatric patients.⁵ Therefore, one needs to be cautious in comparing results across studies and regions.

In a multicentre survey of blindness and visual impairment in a general Chinese population aged ≥ 50 years, the frequency of visual impairment ranged between 5.4% and 15.8%.^20,21 These authors, however, used different measures and cutoffs for visual impairment (< 20/63 Snellen acuity).²³ In the Hong Kong study of chronic psychiatric patients, uncorrected DVI was defined as 20/40 or worse using the Snellen chart.⁵ Having calculated the frequency of uncorrected DVI in the current sample and using the same cutoff, the frequency of DVI rose to 35.7%, still lower than the 75% reported from Hong Kong.⁵ This discrepancy is likely due to demographic and clinical characteristics between the 2 samples. For example, the mean age of our sample was 10 years younger (37.6 ± 12.6 vs. 48.3 ± 12.1 years) and the duration of illness was over 10 years shorter (8.8 ± 9.5 vs. 20.5 ± 10.9 years). We could not locate any other studies that examined presenting DVI in psychiatric patients.

Visual impairment restricts daily activities including communication, self-care, personal hygiene, safety and mobility,²⁴ which in turn have a negative impact on QoL.²⁵ Multivariate analyses revealed that patients with DVI had a lower QoL only in the domain of general vision compared with the non-DVI group. This was somewhat surprising, given the relevance of visual activity for daily activities. Nonetheless as only inpatients were involved in this study, it is likely that some functions measured by the NEI-VFQ25 could not be accurately assessed in the hospital. Further, QoL measures can be classified into generic (SF-12)¹⁸ and disease-specific (NEI-VFQ25).¹⁹ The advantage of generic instruments is that they allow comparisons across different conditions although they are not sufficiently sensitive to identify small changes in QoL. Disease-specific instruments are more sensitive, but they are limited to measurement of the QoL dimensions of the particular disease. This could explain the non-significant difference between the DVI and non-DVI patients in the SF-12 scores.

Consistent with findings in the literature,^8,26 only patients with ocular disease had more frequent DVI, which is an expected finding. A number of demographic and clinical variables, such as age,²¹ antipsychotic medications,²⁶ psychiatric disorders,²⁴ major medical conditions,⁸ body mass index,²⁷ and smoking²⁸ may contribute to DVI, but these factors were not significantly associated with DVI in this study. The reasons for this lack of additional risk factors are unclear, but may be due to our relatively young sample, in which presence of ocular disease overpowered weaker correlates, calling for larger studies.

The results of this study should be interpreted with caution because of its limitations. First, this sample originated only from a single, university-affiliated psychiatric hospital, limiting the generalisability of findings to other psychiatric settings in China. Second, some variables, such as major medical conditions and ocular diseases, were only ascertained from medical records, rather than by comprehensive examination, and might have biased the findings to an uncertain extent. Third, some variables that may influence visual function, such as the cumulative amount of lifetime psychotropic drugs, were not examined. Fourth, the sample size was relatively small, and might have limited the power to detect more significant determinants of DVI. Future studies with a larger sample size are needed. Finally, the impact of DVI on patients’ functional outcomes in the community could not be measured directly.

In conclusion, inpatients in a university-affiliated Chinese psychiatric centre had less DVI than reported previously in a study from Hong Kong⁵ that assessed an older sample and used different methodologies. Distant visual impairment was only related to the presence of ocular disease, and had a negative impact on vision-related QoL. Considering the impact of DVI on daily functioning and QoL, enquiring about eyesight and performing regular eye examinations should become a routine part of the comprehensive health assessment of patients with severe mental illness. Since such patients are less likely to see general practitioners than the general population for a whole host of health conditions,²⁹ psychiatric care providers should engage in the simple clinical assessment and screening and facilitate referrals as needed in order to improve the patients’ overall outcome and functioning.³⁰

Declarations

Dr Christoph U. Correll has been a consultant and / or advisor to or has received honoraria from: Actelion, Alexza; Bristol-Myers Squibb; Cephalon; Eli Lilly; Genentech; Gerson Lehrman Group; IntraCellular Therapies; Lundbeck; Medavante; Medscape; Merck; Janssen/J&J; Otsuka; Pfizer; ProPhase; Roche; Sunovion; Takeda; Teva; and Vanda. He has received grant support from Bristol-Myers Squibb; Janssen/J&J; and Otsuka.

Acknowledgements

This study was supported in part by grants from the National Natural Science Foundation of China (81171270; 30800367; 30770776), the Beijing Nova Program of the Beijing Municipal Science and Technology Commission (2008B59). No investigator benefited from participating in this study. The authors are grateful to all clinicians involved in this study.

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