Vision, quality of life and depressive symptoms after first eye cataract surgery

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1 bs_bs_banner doi: /psyg PSYCHOGERIATRICS 2013; 13: ORIGINAL ARTICLE Vision, quality of life and depressive symptoms after first eye cataract surgery Michelle L. FRASER, 1 Lynn B. MEULENERS, 1 Andy H. LEE, 2 Jonathon Q. NG 3,4 and Nigel MORLET 3,4 1 Curtin-Monash Accident Research Centre (C-MARC), 2 School of Public Health, Curtin University, 3 Eye & Vision Epidemiology Research Group and 4 Centre for Health Services Research, School of Population Health, University of Western Australia, Perth, Western Australia, Australia Correspondence: Ms Michelle Fraser MPhil, Curtin-Monash Accident Research Centre (C-MARC), School of Public Health, Curtin University, Perth, WA 6845, Australia. M.Fraser@curtin.edu.au Financial support: None. Financial disclosure: No author has a financial or proprietary interest in any material or method mentioned. Received 5 December 2012; revision received 24 June 2013; accepted 5 August Key words: cataract surgery, cataracts, depression, first eye, quality of life. Abstract Background: Cataract affects not only vision, but also performance of everyday tasks, participation in social activities, quality of life and possibly depression. Depression is a major health issue for older adults. It is estimated that 6% 20% of community-dwelling older Australians experience depression. The aim of this study was to investigate changes in visionrelated quality of life and depressive symptoms after first eye cataract surgery and to determine which visual measures affect the change in these outcomes. Methods: In 2009 and 2010, 99 participants with bilateral cataract were recruited. Visual measures including visual acuity, contrast sensitivity and stereopsis were assessed 1 week before and 12 weeks after first eye cataract surgery. Vision-related quality of life was measured using the 25-item National Eye Institute Visual Function Questionnaire. Depressive symptoms were assessed by the 20-item Center for Epidemiological Studies Depression Scale. Separate regression analyses were undertaken to determine the association between visual measures and changes in vision-related quality of life and depressive symptoms after first eye cataract surgery. Results: Overall, vision-related quality of life improved after first eye cataract surgery. There was a small, non-clinically significant improvement in depressive symptoms after surgery. Improvement in vision-related quality of life after first eye cataract surgery was associated with improved contrast sensitivity in the operated eye (P < 0.001), whereas improvement in depressive symptoms after surgery was associated with improved stereopsis (P = 0.032). Conclusions: Contrast sensitivity and stereopsis, but not visual acuity, were significant factors affecting improvement in vision-related quality of life or depressive symptoms after first eye cataract surgery. INTRODUCTION Cataract affects not only vision, but also performance of everyday tasks, participation in social activities, quality of life and possibly depression. 1 Depression is a major health issue for older adults. It is estimated that 6% 20% of community-dwelling older Australians experience depression. 2,3 Vision-related quality of life (VRQOL) is a measure of the impact of visual impairment on daily activities and quality of life. 1,4 Evidence has suggested that first and second eye cataract surgery significantly improve VRQOL. 5 8 However, the majority of studies used VRQOL instruments that focused only on the performance of daily activities. 9 Social and mental impacts of visual impairment are now recognized as important outcomes of cataract surgery. Recently, VRQOL instruments, such as the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25), have incorporated these outcomes. 10 The impact of cataract surgery on depression is uncertain. A UK-based randomized controlled trial involving women aged over 70 years, reported a small 237

2 M. L. Fraser et al. but significant improvement in depressive symptoms after first eye cataract surgery. 7 Other studies have found no significant change in depressive symptoms after first and/or second eye cataract surgery. 6,11 16 However, the non-significance may be due to insufficient power with small samples typically less than 50 patients. Many studies that examined VRQOL and depression did not clarify whether participants underwent cataract surgery on the first, second or both eyes, or they analyzed all participants together. However, cataracts are usually bilateral and public hospital patients typically wait long periods before first and second eye surgery. It is likely that each surgery has different effects on the overall functioning of bilateral cataract patients. 5,17 For example, although first eye surgery can lead to significant visual improvements, it can result in large differences in vision between the operated and un-operated eyes for some bilateral patients as well as poor stereopsis. 5,18 It remains unclear which measures of vision affect change in VRQOL and depression following first eye cataract surgery. A Spanish prospective study of 104 bilateral cataract patients reported that the influence of visual measures on VRQOL changed throughout the different stages of cataract surgery. 19 Before first eye surgery, binocular visual acuity was associated with VRQOL. However, after first and second eye surgery, stereopsis was significantly associated with VRQOL. 19 A study of 154 elderly women also found that change in VRQOL after first eye surgery was most strongly associated with change in stereopsis, followed by binocular contrast sensitivity; it was least associated with change in visual acuity. 20 The majority of studies that examined change in depressive symptoms only included visual acuity measures. To address the gaps in the literature, this study investigated VRQOL and depressive symptoms before and after first eye cataract surgery. The aim was to determine which particular visual measures affect changes in these outcomes for patients with bilateral cataract. MATERIALS AND METHODS Study design A prospective cohort study was undertaken. Older adults with bilateral cataract were assessed before and after first eye cataract surgery. Ethical approval was obtained from the Curtin University Human Research Ethics Committee (Perth, WA, Australia) and the three Perth public teaching hospitals involved in the study. Participants A total of 99 participants were recruited from the three hospitals from October 2009 to December Participants were eligible if they were aged 55 years or older, drove, had bilateral cataract and were scheduled to undergo first eye cataract surgery by phacoemulsification. Participants were excluded if they had a confirmed diagnosis of dementia, Parkinson s disease or significant psychosis, were wheelchair bound, had other significant ocular conditions, were scheduled for combined ocular surgery or did not speak English. Of the 109 eligible patients recruited consecutively, 101 agreed to participate (93%). Two participants were lost to follow-up, leading to a final sample of 99 participants available for analysis. Data collection Informed written consent was obtained from each participant. Participation was entirely voluntary and patients could withdraw at any time without consequence on their cataract treatment. Data were collected during the week before first eye cataract surgery and approximately 12 weeks after surgery. No participant underwent second eye cataract surgery during the follow-up period. Sociodemographic and health information were solicited from individuals at baseline. Their medical records were also reviewed to confirm these details, other ocular conditions, and intraoperative or postoperative complications. At both assessments, three visual tests were performed under standard conditions. Current correction was used for visual testing if participants wore their corrective lenses for daily activities. Visual acuity (surgery eye, non-surgery eye and binocular) was measured using an Early Treatment Diabetic Retinopathy Study chart. 21 The Early Treatment Diabetic Retinopathy Study chart incorporates specific design criteria, including five letters on every line and geometric progression of letters, that make it more accurate than other commonly used visual acuity charts, such as the Snellen chart. Scores were expressed on a logarithm of the minimum angle of resolution (logmar) scale. LogMAR scores are the logarithm of decimal visual acuity. For example, a visual acuity score of 6/6 on the Snellen chart is 238

3 Quality of life after cataract surgery equivalent to 0.0 logmar and 6/12 is equivalent to 0.3 logmar. Each letter on the chart has a score value of 0.02 log units and each line has a value of 0.1 log units, with higher scores representing poorer visual acuity. Those who could not read any letters were assigned a score of 1.3 logmar units. Contrast sensitivity (surgery eye, non-surgery eye and binocular with current lens correction) was measured using a Pelli Robson chart in log units. 22 Stereopsis was assessed by the Titmus Fly Stereotest (Stereo Optical Co., Inc., Chicago, IL, USA), which measured disparity from to log seconds of arc. Participants who could not see any image were assigned a score of log seconds of arc. Cognitive ability was assessed using the Mini-Mental State Examination. 23 VRQOL was assessed via the researcheradministered NEI VFQ This questionnaire provided a continuous composite score and 12 subscale scores, which included general health, general vision, near vision, distance vision, driving, peripheral vision, colour vision, ocular pain, role limitations, dependency, social function and mental health. Each item on the questionnaire was measured on a five- or sixpoint scale, giving total scores ranging from 0 to 100 points. Each subscale contained between one and four items. To obtain each subscale score, its individual item scores were averaged. To obtain the composite score, 11 of the subscale scores were averaged. Per the instructions by Mangione et al., the general health subscale was not included. 10 The composite and subscale scores were measured on a scale from 0 to 100 with higher scores representing better VRQOL. 10 Depressive symptoms were measured using the 20-item Center for Epidemiological Studies Depression Scale. 24 A continuous overall score ranging from 0 to 60 was produced, with higher scores representing more depressive symptoms. It is generally considered that a score of 16 or higher on the scale represents the presence of significant depressive symptoms. 24 Statistical analysis Paired t-tests were applied to compare visual, cognitive, VRQOL and depressive symptom variables before and after cataract surgery. Separate stepwise regressions were then performed to investigate which particular changes in visual measures affected change in VRQOL and depressive symptom scores after surgery, while the pre-surgery scores were controlled to correct for regression to the mean. 25 For each visual measure considered in the model (surgery eye visual acuity, non-surgery eye visual acuity, surgery eye contrast sensitivity, non-surgery eye contrast sensitivity and stereopsis), the change from before to after surgery was calculated. Because binocular measures of visual acuity and contrast sensitivity were highly correlated with visual acuity and contrast sensitivity in the better eye before and after surgery, they were excluded for consideration in the final models. Potential confounding variables considered in the regression models were age, gender, country of birth, education, marital status, living situation, number of chronic health conditions, other eye conditions, receipt of new glasses after surgery and change in Mini-Mental State Examination score. Significance of the visual and other variables were tested based on two-sided P-values being less than All statistical analyses were performed using the SPSS package, version 18 (SPSS Inc, Chicago, IL, USA). RESULTS The 99 participants were aged 55 to 88 years with a mean age 1 SD of years at baseline. About half the participants were men (50.5%) and were born in Australia (46.5%). Fifty-four participants (54.5%) were married and 37 (37.4%) lived alone. For the majority (72.7%), primary or secondary school was their highest level of education. Participants had on average chronic conditions, the most common being circulatory conditions (79.8%), followed by musculoskeletal conditions (55.6%) and diabetes (31.3%). Fourteen participants (14.1%) experienced mild comorbid eye conditions in addition to cataract. In terms of type of cataract, 72.7% had nuclear sclerotic cataract, 1.0% cortical, 4.0% posterior subcapsular and 22.2% had a combination of types in their first surgery eye. There were no serious intraoperative or postoperative cataract surgery complications. Five participants (5.1%) experienced minor complications such as temporary inflammation. At the 12-week follow-up, 22.2% had received new glasses or lenses prescribed for their post-surgery vision. Visual and cognitive test scores, VRQOL and depressive symptom composite scores before and after first eye surgery are presented in Table 1. After surgery there were statistically and clinically significant improvements in surgery eye visual acuity 239

4 M. L. Fraser et al. Table 1 Visual, cognitive, vision-related quality of life and depressive symptom characteristics of bilateral cataract patients before and after first eye cataract surgery (n = 99) Outcomes Before surgery (mean 1 SD) After surgery (mean 1 SD) P-value Visual acuity (logmar units) Surgery eye 0.57 ± ± 0.16 <0.001 Non-surgery eye 0.32 ± ± Binocular 0.23 ± ± 0.13 <0.001 Contrast sensitivity (log units) Surgery eye 1.21 ± ± 0.17 <0.001 Non-surgery eye 1.47 ± ± Binocular 1.55 ± ± 0.16 <0.001 Stereopsis (log seconds of arc) 2.22 ± ± Mini-Mental State Examination score ± ± VRQOL score ± ± 9.18 <0.001 Depressive symptoms score 8.87 ± ± Lower scores represent better performance. logmar, logarithm of the minimum angle of resolution; VRQOL, vision-related quality of life. Table 2 Vision-related quality of life subscale scores before and after first eye cataract surgery (n = 99) Subscale scores Before surgery (mean 1 SD) After surgery (mean 1 SD) P-value General health ± ± General vision ± ± <0.001 Ocular pain ± ± Near activities ± ± <0.001 Distance activities ± ± <0.001 Vision-specific social functioning ± ± Vision-specific mental health ± ± <0.001 Vision-specific role difficulties ± ± <0.001 Vision-specific dependency ± ± Driving ± ± <0.001 Colour vision ± ± Peripheral vision ± ± (P < 0.001), binocular visual acuity (P < 0.001), surgery eye contrast sensitivity (P < 0.001), binocular contrast sensitivity (P < 0.001) and stereopsis (P = 0.001). There was no significant change in non-surgery eye contrast sensitivity (P = 0.179). Non-surgery eye visual acuity significantly worsened by 0.03 logmar units (P = 0.015). However, as clinicians often define a change of 0.1 logmar as meaningful, this decline was not considered to be clinically significant. After surgery, the composite VRQOL score significantly improved on average by points. The depressive symptoms score also significantly improved on average by points, though the difference was not considered to be clinically significant. Overall, the composite VRQOL score of 85 participants improved after surgery (85.9%), 1 remained the same (1.0%) and 13 declined (13.1%). The depressive symptoms score improved overall among 49 participants (49.5%), remained the same for 20 participants (20.2%) but worsened in 30 participants (30.3%). Table 2 compares the VRQOL subscale scores before and after first eye surgery. Before surgery, VRQOL subscale scores were poorest for general health, general vision and driving. Scores were highest for colour vision, vision-specific social functioning and vision-specific dependency; all had mean scores over 90 points. Following surgery, significant improvements in mean scores were evident for all subscales except general health, ocular pain and colour vision, with the lowest scoring subscales being the same as those before surgery. Tables 3 and 4 show the results of stepwise regression analyses of visual measures affecting change in VRQOL score and depressive symptoms score, respectively, after first eye cataract surgery. After 240

5 Quality of life after cataract surgery Table 3 Significant factors affecting change in vision-related quality of life after first eye cataract surgery (n = 99) Variable Coefficient 95%CI P-value Constant <0.001 VRQOL before surgery <0.001 Surgery eye contrast <0.001 sensitivity (change) Obtained new glasses <0.001 after surgery Age (years) Country of birth (non-australian) Estimates from stepwise regression analysis. Variables excluded were gender, number of chronic health conditions, education, marital status, living situation, other eye conditions, change in Mini-Mental State Examination score, change in surgery eye visual acuity, non-surgery eye visual acuity, non-surgery eye contrast sensitivity and stereopsis. CI, confidence interval; VRQOL, vision-related quality of life. Table 4 Significant factors affecting change in depressive symptoms after first eye cataract surgery (n = 99) Variable Coefficient 95% CI P value Constant Depressive symptoms <0.001 before surgery Stereopsis (change) Number of chronic health <0.001 conditions Obtained new glasses after surgery Age (years) Estimates from stepwise regression analysis. Variables excluded were gender, country of birth, education, marital status, living situation, other eye conditions, change in Mini-Mental State Examination score, change in surgery eye visual acuity, non-surgery eye visual acuity, surgery eye contrast sensitivity and non-surgery eye contrast sensitivity. CI, confidence interval. baseline VRQOL was controlled, change in surgery eye contrast sensitivity was the only significant visual measure affecting change in VRQOL after first eye cataract surgery. VRQOL score significantly improved as surgery eye contrast sensitivity improved (P < 0.001). In addition, having received new glasses postsurgery was significantly associated with improvement in VRQOL score (P < 0.001). In contrast, advancing age (P = 0.002) and being non-australian born (P = 0.036) were negatively associated with the VRQOL score (Table 3). After baseline depressive symptoms were controlled, change in stereopsis was the only visual measure affecting the change in depressive symptoms after first eye cataract surgery. Depressive symptoms significantly improved as stereopsis improved (P = 0.032). Having more chronic health conditions (P < 0.001) and advancing age (P = 0.009) were significantly associated with poorer depressive symptoms score, while receiving new glasses after surgery (P = 0.001) was associated with improved scores (Table 4). Interactions between the significant main effects were not significant when tested in the regression models. DISCUSSION This study found that change in surgery eye contrast sensitivity after first eye cataract surgery was the only visual measure significantly associated with improvement in VRQOL, after we controlled for the baseline VRQOL of each individual. In addition, change in stereopsis after first eye cataract surgery was significantly associated with improvement in depressive symptoms, whereas visual acuity had little effect on either outcome. It has been reported that visual acuity is strongly related to VRQOL before first eye cataract surgery but that stereopsis and contrast sensitivity have more influence after surgery. 19,20 For example, one study suggested that while change in VRQOL after first eye surgery was associated with binocular contrast sensitivity, it was most strongly related to stereopsis. 20 In contrast, change in VRQOL was most affected by change in visual acuity in the first surgery eye and not contrast sensitivity according to another study. 26 This study, however, used the Activities of Daily Vision Scale, which focuses strongly on activities that require visual acuity. The environment contains many low-contrast stimuli, meaning contrast sensitivity is necessary for the performance of a wide range of daily activities. 20,27 It is therefore plausible that contrast sensitivity plays an important role in VRQOL. Although contrast sensitivity is usually correlated with visual acuity, some cataract patients may have low contrast sensitivity, even when their visual acuity is within normal limits. 28 Consequently, the current focus on visual acuity in ophthalmology practice to determine visual disability and prioritize patients for cataract surgery may overlook patients who are significantly impaired. Only one previous study examined visual measures and change in depressive symptoms after first eye surgery, but it found that change was not associated with any visual measures. 20 The mechanism by which stereopsis may affect depression is currently unclear. 241

6 M. L. Fraser et al. However, a study of 200 older people in Taiwan concluded that while visual acuity was associated with performance of tasks, stereopsis was important for generic quality of life and well-being outcomes. 29 Receiving new glasses after first eye surgery was significantly associated with improvement in both VRQOL and depressive symptoms. Therefore, patients who wait to purchase appropriate glasses until after second eye surgery should reconsider and be advised accordingly. The NEI VFQ-25 subscale scores before surgery were very consistent with those previously reported for cataract patients in the USA. 10 As expected, scores were poorer than those previously reported for a reference population with no visual impairment. This reference population scored in the 90s for all subscales except general health (69), general vision (83) and driving (87). 10 This study demonstrated significant improvements in the composite VRQOL score as measured by the NEI VFQ-25 after first eye cataract surgery. This instrument incorporates the influence of visual impairment on social functioning, mental health, role difficulties, dependency and daily activities. 10 Large improvements were observed for subscales such as general vision, near activities, distance activities and driving. Interestingly, large improvements were also found for the vision-specific role difficulties (17 points) and vision-specific mental health (14 points) subscales, suggesting that first eye cataract surgery may have additional social, emotional and mental health benefits for patients. A small improvement in depressive symptoms was also recorded after first eye cataract surgery, although the magnitude of change did not have any clinical significance. 30 The finding was consistent with the literature, which similarly reported no significant difference in depression after surgery. 6,12,15 The low prevalence of depressive symptoms before surgery in the current study may provide a plausible explanation. However, depression is a complex construct with multifactorial causes and pathways. 2 A single factor such as cataract surgery may not be sufficient to have a significant impact on depressive symptoms. 15 A limitation of this study was the lack of a comparison group, which makes it difficult to establish cause and effect. Reporting bias also poses an intrinsic risk to validity due to the nature of self-reported VRQOL and depressive symptom data. In addition, visual measures including field of view, disability glare and refraction were not collected. The sample size of this study also did not allow for subgroup analyses to determine factors associated with improvement and non-improvement in VRQOL and depression. This is an area for further research. In conclusion, first eye cataract surgery was beneficial for VRQOL among bilateral patients but had no clinically significant effect on depressive symptoms. Contrast sensitivity or stereopsis, but not visual acuity, were associated with improvement in VRQOL and depressive symptoms after first eye cataract surgery. The role of these visual measures in VRQOL and depression should be further investigated and considered by clinicians when determining the effectiveness of first eye surgery and prioritizing patients for second eye surgery. ACKNOWLEDGMENTS No financial support was received for this study. REFERENCES 1 Margolis MK, Coyne K, Kennedy-Martin T, Baker T, Schein O, Revicki DA. 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