Psychological distress is associated with vision-related but not with generic quality of life in patients with visual field defects after cerebral lesions.

Considerably diminished quality of life (QoL) is observed in patients with visual field defects after lesions affecting the visual pathway. But little is known to what extent vision-and health-related QoL impairments are associated with psychological distress. In 24 patients with chronic visual field defects (mean age=56.17±12.36) the National Eye Institute-visual functioning questionnaire (NEI-VFQ) for vision-related QoL, the Short Form Health Survey-36 (SF-36) for generic QoL and the revised Symptom-Checklist (SCL-90-R) were administered. Cases with clinically relevant SCL-90-R symptoms were defined. Demographic, QoL and visual field parameters were correlated with SCL-90-R scales. About 40% of the investigated patients met the criteria for the definition of psychiatric caseness. 8/12 NEI-VFQ scales correlated significantly with SCL-90-R phobic anxiety (r-range −0.41 to −0.64, P<0.05), 5/12 NEI-VFQ scales correlated with SCL-90-R interpersonal sensitivity (−0.43 to −0.50), and 3/12 with SCL-90-R depression (−0.51 to −0.57) and obsessive-compulsiveness (−0.41 to −0.43). In contrast, only 1/8 SF-36 scales correlated significantly with SCL-90-R depression, phobic anxiety and interpersonal sensitivity (−0.41 to −0.54). No substantial correlations were observed between visual field parameters and SCL-90-R scales. Significant correlations of SCL-90-R with NEI-VFQ but not with SF-36 suggest that self-rated psychological distress is the result of diminished vision-related QoL as a consequence of visual field loss. The extent of visual field loss itself did not influence the rating of psychological distress directly, since SCL-90-R symptoms were only reported when diminished vision-related QoL was present. Patients with reduced vision-related QoL due to persisting visual field defects should therefore be offered additional neuropsychological rehabilitation and supportive psychotherapeutic interventions even years after the lesion.


Introduction
Visual field defects after lesions to the visual pathway lead to impairments in activities of daily life such as reading, driving, or overall orientation and may therefore have severe impact on the patients` well-being and quality of life (QoL). 1 Objective functional impairments of vision which may cause diminished vision-related QoL are measurable with the National Eye Institute visual functioning questionnaire (NEI-VFQ). 2,3 Patients with visual field loss often show psychological distress which may be related to the vision impairment, but this is not sufficiently captured by the mental health subscale of NEI-VFQ. Since there is no questionnaire available that specifically targets psychological distress in the visually impaired, in the present study the Symptom-Checklist-90-revised (SCL-90-R) was applied to adequately measure mental distress. 4 In studies which focus on the impact of vision impairment on subjective vision-related QoL, the NEI-VFQ is often used as a valid and reliable instrument. 2 This questionnaire was originally designed for the assessment in ophthalmologic diseases. 3 More recently, some studies focused on the assessment of visionrelated QoL in patients with visual field loss after cerebral damage. [5][6][7] Here, it was demonstrated that diminished vision-related QoL was significantly related to the extent of the visual field loss. 7 However, no study to date assessed the subjective perception of psychological symptoms by a dedicated symptom check list, such as the SCL-90-R, to assess self-rated distress in patients with visual field loss. We hypothesized an association of SCL-90-R results with visual field loss as well as with vision-related QoL but not with general health-related QoL.
Many studies measured self-estimated disabilities after stroke using generic questionnaires of general health-related QoL. [8][9][10] However, none of these studies considered visual field defects as a comorbidity with possible influence on the patients' QoL and psychological distress, although it is known that visual field loss occurs in as many as 10% of stroke patients. 11 Additionally, a number of studies have shown that the incidence of neuropsychiatric conditions is high in post-stroke patients. Research focuses on poststroke depression, [12][13][14] apathy and anxiety. 13,[15][16][17] Post-stroke depression is associated with greater cognitive impairment, 18 increased mortality, 19 and poorer recovery of activities of daily living skills. 20 Again, none of these studies considered the possible effect of comorbid visual field defects.
Woessner and Caplan argued that since items of the SCL-90-R also cover general consequences of stroke, answers of neurological patients have to be interpreted in the context of the underlying disease. 21 Thus, 14 items of the SCL-90-R, mainly items of the obsessivecompulsive, hostility and depression scale, reflect common neurological symptoms following traumatic brain injuries that impede clinical interpretation. 22 Nevertheless, the SCL-90-R is a useful instrument in cerebrally damaged patients. Kaplan and Miner used SCL-90-R to test 17 patients with brain tumors and concluded that the SCL-90-R is an appropriate indicator of emotional distress and somatic effects of structural brain injury. 23 Linn, Allen and Willer tested 60 patients and their partners with the scales anxiety and depression six years after traumatic brain injury: 24 70% suffered from depression and 50% showed anxiety symptoms while also their partners demonstrated significant affective symptoms (73% depression, 55% anxiety). Baker et al. also tested patients after traumatic brain injuries with SCL-90-R and stated that this patient group can be analysed with this self-assessment inventory. 25 McCleary et al. tested 105 patients six months after traumatic brain injury and found that 42% reported depressive symptoms. 26 27 In visually impaired patients with lesions different from stroke, neuropsychiatric conditions were observed, too. For instance, in patients with diabetic retinopathy levels of depression and anxiety were clinically significant. 28,29 Moreover, declining vision in diabetes was found to be associated with substantially reduced QoL. 28 Symptom severity and emotional distress due to vision loss were related with self-reported disability in persons with low vision. 30 Psychological distress and depression were also common in patients with refractive error, 31 myopia, 32,33 and amblyopia. 34 Biofeedback-visual training in myopic patients was found to improve the psychological mental state and subjective vision abilities, but not visual acuity as determined by objective computer tests. 32,33 Reimer et al. reported clinically relevant distress measured with the SCL-90-R in every second patient before plaque radiotherapy. 35 Vision-and health-related QoL were impaired in these patients and further reduced after radiotherapy. Therefore, QoL data should be regularly assessed in neuroophthalmic patients to provide psychosocial treatments for patients at risk for low QoL and high distress. 35 Self-reported psychological distress was reported to be more appropriate to predict subjective QoL than clinician-rated symptom severity. 36 In the present study we therefore assessed subjective psychopathological symptoms with the SCL-90-R in cerebrally damaged patients with visual field defects. Additionally, vision-and health-related QoL was measured to allow for correlation analyses of QoL data with self-rated psychological distress measured by the SCL-90-R.

Materials and Methods
All questionnaires were self-administered. Data was collected as part of a cross-sectional study which included 24 brain-damaged patients with visual field loss due to several reasons (Table 1). Patients were investigated at a late follow-up of a neuropsychological visu-al field training and had documented visual field loss after cerebral damage indicated by standard perimetry and campimetry. Verbal intelligence was measured with a German verbal intelligence test. Best corrected near and distance visual acuity was measured monocularly using Landolt-ring test charts.
The mean time from lesion onset to data acquisition was 2.0±2.7 years (mean age ± standard deviation). In 13 cases the lesion was older than twelve months. In the whole sample the visual field defect was assessed with a computer campimetric method and standard automated perimetry with the Rodenstock Perimat 206. 37 Figure 1 shows the distribution of detected stimuli and the proportions of relative and absolute defects in perimetric measurements for both eyes. All patients were treated according to the ethical standards of the Declaration of Helsinki (1964).
The validated German 39-item version of the NEI-VFQ was administered for assessment of vision-related QoL 2 and the German Health Survey Short Form-36 (SF-36) for the collection of data concerning general health-related QoL based on the experiences during the last four weeks. 38 The German SCL-90-R revised version was assessed for measuring the subjective perception of psychological symptoms assessing the degree of self-rated distress over a time period of four weeks. 4 Cases with clinically relevant psychological symptoms were defined  according to T-criteria. 4 Demographic, QoL (NEI-VFQ and SF-36) and visual field parameters were correlated with SCL-90-R scales using the Spearman coefficient. NEI-VFQ and SF-36 results were compared by univariate analysis of variance between patients meeting the SCL-90-R case criteria and those who did not. Statistical analyses were carried out with SPSS 15.0.

Results
Vision-and health-related quality of life results of patients with visual field loss: National Eye Institute-Visual Functioning Questionnaire and German Health Survey Short Form-36 The mean values of the investigated patients were 20 points or more below those of a reference group in the following NEI-VFQ subscales: 39     Four patients showed T-values ≥60 for the positive symptom distress index and T-values ≥60 for the positive symptom total were observed in eight patients.

Article
Group comparison of quality of life questionnaire results according to Symptom-Checklist-90-revised case definitions Figure 2 shows NEI-VFQ mean values of patients according to the categorization in cases and no cases and F-values for group comparisons. Apparently cases had descriptively lower NEI-VFQ results in all subscales. However, only mental health and role difficulties scores significantly differed between groups. Figure 3 shows SF-36 mean values of patients according to the categorization in cases and no cases and F-values for group comparisons. Except for subscales bodily pain, vitality, social functioning and emotional well-being, cases showed lower scores. However, only physical functioning and role limitations (emotional) showed significant group differences ( Figure 3).
Correlation analyses between vision impairment, visual field and demographic variables with National Eye Institute-visual functioning questionnaire and Symptom-Checklist-90-revised Visual acuity Distance and near visual acuity (always best corrected) significantly correlated with some of the NEI-VFQ subscales. Distance visual acuity showed correlations with 6/12 NEI-VFQsubscales (r-range from 0.44 to 0.66, all P<0.05) and with the composite score (r=0.50, P<0.05). Near visual acuity correlated significantly with NEI-VFQ scale near activities (r=0.44, P<0.05), and SCL-90-R somatization (r=0.45, P<0.05). Correlations are shown in detail in Table 3.

Visual field
The intact visual field (measured as the number of correctly detected stimuli in % in computer campimetry) showed significant correlations with 9/12 NEI-VFQ subscales (r-range from 0.43 to 0.68, all P<0.05) and with the composite score (r=0.66, P<0.001). The absolute defect of the visual field, i.e. the number of missed stimuli in the perimetric visual field test in %, correlated with 10/12 NEI-VFQ subscales (r-range from -0.49 to -0.79, P<0.05) and with the composite score (r=-0.76, P<0.001). As expected, the number of detected stimuli in perimetry (in %) also showed significant correlations with 10/12 NEI-VFQ-sub-

Correlation analyses between vision-and health-related quality of life data and Symptom-Checklist-90-revised
There were a number of moderate correlations between vision-related QoL data as measured with the NEI-VFQ and SCL-90-R subscales (Table 4). Also the GSI was related to general health (r=-0.42) and mental health (r=-0.44).
Correlations with SF-36 results for healthrelated QoL were low and in most cases not significant. Only the SF-36 subscale role limitations due to emotional problems showed significant correlations with SCL-90-R interpersonal sensitivity (r=-0.41), depression (r=-0.54; P<0.01), and the total score (r=-0.42).

Discussion
In the present study psychological distress was self-evaluated with the SCL-90-R in patients with visual field defects after cerebral damage. Since psychological distress seems to be a better predictor of reduced QoL than symptom severity,36 the relation between vision-and health-related QoL measured with the NEI-VFQ and SF-36 with SCL-90-R subscales was investigated.
The observed relations between visual acuity, visual field parameters, and NEI-VFQ con- firm that the NEI-VFQ is an appropriate instrument to assess vision-related QoL after visual field loss. The results support previous studies demonstrating that the extent of visual field loss is related to the extent of reduced visionbut not health-related QoL. [5][6][7] We observed negative correlations between vision-related QoL and self-rated psychological distress as measured with the SCL-90-R. Thus, patients with higher vision-related QoL were less affected by psychopathological symptoms than patients with lower vision-related QoL. However, this relation was present for only some vision-related QoL dimensions. Thus, SCL-90-R phobic anxiety, interpersonal sensitivity, depression, and obsessive-compulsiveness were related to vision-related QoL.

Article
Except for the SCL-90-R subscale somatisation that showed an unexpected positive correlation with near visual acuity, no relations between psychopathological distress and vision impairment parameters were observed. Thus, whereas vision-related QoL was associated with SCL-90-R results, the objective results of assessment of visual functioning were not. Although patients with visual field defects clearly reported diminished visionrelated QoL, the extent of the visual field loss itself did not cause psychological distress in a direct way but mediated by vision-related QoL. This conclusion is supported by comparisons of patients that met case definition criteria of the SCL-90-R who showed consistently lower vision-related QoL than patients without clinically relevant psychological symptoms. With only a few exceptions reduced health-related QoL measured by the SF-36 was not related with SCL-90-R subscales. Also, SF-36 results did not correlate with vision parameters.
Verbal intelligence was positively correlated with NEI-VFQ social functioning, mental health and dependency, but negatively with SCL-90-R somatization, interpersonal sensitivity and phobic anxiety. This implies that persons with higher verbal abilities demonstrate higher NEI-VFQ scores, foremost in subscales that imply mental well-being and interaction with others. Moreover, patients with a higher verbal intelligence complained less frequently about somatization or anxieties. Thus, SCL-90-R results also seem to depend on intellectual abilities as reported earlier. 41 Further studies should focus on replicating this finding in larger samples.

Conclusions
We finally conclude that brain-damaged patients with visual field loss resulting in reduced vision-related QoL are at greater risk to suffer from psychological distress or to develop psychopathological symptoms. Psycho -logical distress was independent of the extent of visual field loss but related to diminished vision-related QoL. Because of the risk of suffering psychological distress, patients with persisting visual field defects should be offered supportive psychotherapeutic interventions in addition to neuropsychological rehabilitation even many years after the lesion.