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Abstract
Aim To evaluate vision-related quality of life in persons with branch retinal vein occlusion (BRVO) using the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25).
Design Observational, cross-sectional, interviewer-administered study.
Methods 46 patients with unilateral BRVO were included in this study. Scores on the VFQ-25 were analysed and converted to scaled scores per NEI VFQ-25 algorithms. Clinical data including age, gender, employment status, living arrangements, visual acuity, number of systemic diseases and duration of BRVO were also recorded. Subscale results were compared with previously published data, and subgroup analyses were performed.
Results Mean adjusted subscale responses among BRVO patients were higher (except for ocular pain) than known averages in patients with diabetic retinopathy, central retinal vein occlusion, age-related macular degeneration and low vision, but lower than known averages in a reference group of people without ocular disease. Subscale responses correlated significantly with visual acuity in the involved eye. This observation held true in eight of 12 subscales, even in patients who maintained vision of 20/25 or better in the uninvolved eye. The General Health subscale and number of systemic diseases correlated significantly with both the General Vision and Peripheral Vision subscale scores. There was no correlation between subscale responses and age.
Conclusions BRVO is a retinal vascular disease that is associated with a decrease in vision-related quality of life as determined by the VFQ-25. A decrease in VFQ-25 score is correlated with involved eye visual acuity, even when good visual acuity is maintained in the uninvolved eye.
- Quality of life
- branch retinal vein occlusion
- VFQ
- BRVO
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Venous occlusive disease is a common retinal vascular disorder.1 Known risk factors include hypertension, diabetes, hyperlipidaemia, glaucoma, smoking and age-related atherosclerosis.2 3 Branch retinal vein occlusion (BRVO) may lead to severe vision loss from macular oedema, macular ischaemia and vitreous haemorrhage. While the pathological consequences of a BRVO have been studied, the effect of BRVO on vision-related quality of life has not been evaluated.
The National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) is a questionnaire that was designed to evaluate vision-related quality of life (QOL) and to test the psychometric properties of diseases that cause vision loss.4 This questionnaire has been used to assess vision-related quality of life in patients with cataract, diabetic retinopathy (DR), age-related macular degeneration (AMD) low vision (LV), central retinal vein occlusion (CRVO) and individuals without ocular disease (REF).4 5
We report the vision-related quality of life in patients with BRVO in one eye assessed with the NEI VFQ-25.
Methods
Individuals with a clinical diagnosis of unilateral branch retinal vein occlusion (BRVO) (ICD 362.36) seen at the Duke University Eye Center between January 1990 and June 2000 were identified by a search of a computerised patient database. The only inclusion criterion was the presence of BRVO. Exclusion criteria were age less than 18 years old and diagnosis by a non-retinal specialist.
Approval was obtained from the Institutional Review Board (IRB # 2287.00.12ER). Eligible persons were asked to participate in a voluntary 20 min survey during their routine clinic appointment or by telephone. It has been demonstrated in the past that this mixed mode of administration does not yield results that are statistically different.6 One of the authors (SHE) administered the survey. The first 46 consecutive patients to complete the survey were included in the study.
The NEI VFQ-25 was used to assess vision-related quality of life in our group of patients. The VFQ-25 addresses 12 subscales: General Health (one question), General Vision (one question), Near Vision (three questions), Distance Vision (three questions), Driving (two questions), Peripheral Vision (one question), Colour Vision (one question), Ocular Pain (two questions), Role Limitations (two questions), Dependency (three questions), Social Functioning (two questions) and Mental Health (four questions).4 Answers to each question on the VFQ-25 were converted to a 100-point scale in which 100 represents the best possible score, and 0 represents the worst. Each subscale represents the average of one or more questions. Guidelines published by the NEI were adhered to when calculating the above scale conversions and subscale scores.7 Additionally, patients were asked about employment status and living arrangements. Clinical variables, including age, gender, most recent Snellen visual acuity and number of comorbid ocular diseases and systemic diseases, were obtained from the medical record. Approximations for visual acuity worse than 20/400 were as follows: counting fingers=20/2000, hand motions=20/4000, light perception=20/8000 and no light perception=20/16 000.8 Snellen vision was converted to logMAR for statistical analysis.
Subscale scores for BRVO patients were compared with previously published data on patients with diabetic retinopathy (DR), central retinal vein occlusion (CRVO), age-related macular degeneration (AMD), low vision (LV) and a reference group (REF) without ocular disease.4 5 Statistical analysis was performed using SAS statistical analysis software (SAS Institute, Cary, North Carolina). The Student t test was used to compare subscale results in persons with BRVO with those with DR, CRVO, AMD, LV and those without ocular disease.
For patients with BRVO, several additional analyses were carried out. The significance of the differences in subscale responses for employment status (working or not) and living arrangement (living alone or not) was assessed using the Wilcoxon rank sum test. Correlations between other variables (visual acuity in affected eye and fellow eye, better-seeing and worse-seeing eye, age, visual acuity better than 20/25 in fellow eye, number of systemic conditions and General Health) and subscale responses were assessed using the Kendall Tau-b correlation coefficient. Associations between the General Health subscale and the remaining subscales, controlling for age and vision, were assessed using the Spearman correlation.
Results
The first 50 consecutive patients to complete the above questionnaire participated in the study. Forty-six patients with unilateral BRVO were included in this analysis; four patients with bilateral BRVO were excluded from the analysis. The average age was 67.8 years (range: 44–83 years). Twenty-three (50%) were female. The median visual acuity (logMAR) in the affected eye at the time of study entry was 0.4771 (∼20/60). Thirty-three eyes had unilateral BRVO with a visual acuity of 20/25 or better in the fellow eye. The mean duration of the occlusion prior to administration of the VFQ-25 was 1.7 years (SD=1.6 years). Patient characteristics are summarised in table 1.
Patient characteristics
The mean subscale responses of all persons with BRVO (n=46) are presented in table 2. These responses were compared with previously published data as described above in the Methods section.4 5 Data from these comparisons with corresponding p values are also presented in table 2.
Summary of subscale responses
Overall, the results of the BRVO group were significantly greater (p<0.05) in all categories when compared with central retinal vein occlusion, 11 of 12 subscales when compared with the LV group, and 10 of 12 subscales when compared with DR and AMD groups (table 2). Patients with BRVO noted a significantly lower subscale response than patients without ocular disease in every category, with the exception of Colour Vision. (table 2).
The results of the analysis comparing subscales by living arrangement and employment status are shown in table 3. No significant difference between vision-related quality of life and living arrangement or employment category was found in any of the VFQ subscales.
Subscale scores in subgoups
The relationship between VFQ-25 subscale scores and visual acuity in the worse-seeing versus better-seeing eye as well as affected (eye with BRVO) versus non-affected eye is shown in table 4. A strong negative correlation between visual acuity in the worse-seeing eye and vision-related quality of life was found in nine of 12 subscales (this correlation was not seen in the General Health, Colour Vision or Social Functioning subscales). Since visual acuity is measured in logMAR units (the lower the value, the better the vision), a negative numerical value of correlation implies a positive relationship with the subscale. This same relationship held true when the data were analysed for affected eye. The worse-seeing eye was the affected eye in 36 of 46 patients included in this analysis (six patients had worse vision in the non-affected eye, and four patients had equal vision in the affected and non-affected eyes). In contrast, no significant correlations were found for the better-seeing eye or for the non-affected eye.
Correlation of subscale response with visual acuity Kendall tau-b correlation (p value)
In order to control for poor vision in the non-affected eye and further determine the specific effect of BRVO on vision-related quality of life, a subgroup analysis was performed, which included only patients with a visual acuity of 20/25 or better in the non-affected eye (table 5). The significant correlation between BRVO and VFQ-25 subscale score was maintained in eight of 12 subscales (this correlation did not hold for General Health, Colour Vision, Dependency or Social Functioning subscales). This was similar to findings when all eyes were included, as described above (table 6).
Subscale responses in 33 patients with unilateral branch retinal vein occlusion and visual acuity of 20/25 or better in the uninvolved eye
Correlation of subscale responses with visual acuity in involved eye of 33 patients with unilateral branch retinal vein occlusion and uninvolved eye 20/25 or better
The number of systemic medical conditions was examined in each of the patients included in this analysis in order to determine whether systemic health was related to vision-related QOL (table 7). This was assessed using the Kendall Tau-b correlation coefficient. There was no correlation between the number of systemic diseases and VFQ-25 subscale scores, except for Colour Vision (p=0.012). Further, a correlation of General Health to each of the subscales was performed and revealed a significant correlation with General Vision and Peripheral Vision. This association was maintained when age and vision were controlled for using the Spearman rank correlation (table 7). Even though these correlations are significant, the correlations are not strong. Vision in the better-seeing eye was not significantly correlated with vision-related QOL (table 8). Finally, patient age did not correlate significantly with VFQ-25 responses (table 9).
Correlation of number of systemic diseases and general health with subscales
Correlation of vision in better-seeing eye with subscales, controlling for general health
Correlation of age with subscales
Discussion
The validity and usefulness of vision-related QOL surveys, including the NEI VFQ-25, have been described previously.4 5 10 It has also been shown that the psychological attitude of the patient towards their health problem is associated with the total average score.9 While loss of vision does not mean loss of ability, our study demonstrates that persons with BRVO experience a subjective negative impact in vision-related QOL. When compared with a reference group without ocular disease, decreases in subscale responses were found to be statistically significant in patients with BRVO in every category with the exception of Colour Vision.
When compared with other vision-threatening ocular disease including DR, CRVO, AMD and low-vision patients, the impact of BRVO on vision-related QOL did not appear to be as great (table 2). While several patients with BRVO reported difficulties with many aspects of daily life, there was no correlation between living arrangements or employment status with VFQ-25 subscale scores.
While the data presented in table 2 demonstrate a correlation between BRVO and VFQ-25 subscale scores, it is possible that this correlation was due to the presence of other ocular problems in the non-involved eye. In order to control for this, we performed a subgroup analysis that included only patients with a visual acuity of 20/25 or greater in the non-involved eye. This group included 33 patients, and the subgroup analysis continued to demonstrate a statistically significant correlation between VFQ-25 subscale scores and visual acuity in the affected eye in eight of 12 subscales (table 6). Therefore, excellent visual acuity in the non-involved eye does not change the observation of BRVO associated with lower vision-related QOL scores shown in table 4.
When compared with persons who have lost vision from CRVO, persons with BRVO had significantly higher indices on each of the VFQ-25 subscale scores. These were significant at the p=0.001 level on the Driving, Peripheral Vision, Dependency and Social Functioning subscales and at the p=0.005 level on the remaining subscales (table 2).
A significantly better quality of life is found in patients with BRVO than in those with DR, CRVO, AMD or LV (table 2). It may be that the majority of LV patients are AMD patients, and thereby the two groups approximate each other. Diabetic retinopathy and age-related macular degeneration also tend to be bilateral disorders, unlike BRVO or CRVO where the majority are unilateral (our study included only unilateral BRVO). This may account for the lower scores generated by persons with DR, AMD or LV, when compared with BRVO.
Patients with BRVO often have systemic vascular disease, including hypertension and diabetes mellitus.2 Because systemic disease and comorbidities can affect VFQ-25 scores, we correlated the number of systemic diseases identified in our series of BRVO patients with VFQ-25 subscale scores (table 7). No significant correlation was found in 11 of 12 categories. This analysis further supports the correlation of BRVO with decreased vision-related QOL scores as identified by the VFQ-25, as the number of systemic diseases was not found to be a confounding variable. A correlation between General Health and General Vision and Peripheral Vision was identified; however, no correlation in the remaining subscales was found. This association was maintained when age and vision were controlled.
Any venous occlusive disease may be associated with a poor visual prognosis.11 12 In the Branch Vein Occlusion Study (BVOS), the mean visual acuity of eyes treated for macular oedema (n=43) was 20/40 (logMAR 0.30) to 20/50 (0.40) after 3 years, while untreated eyes (n=35) stabilised at 20/70 (0.54).11 The median visual acuity included in our analysis was 20/60. We demonstrate that unilateral BRVO with this median visual acuity, even when excellent visual acuity is maintained in the non-involved eye, correlates with a diminished vision-related QOL as measured by the VFQ-25.
Footnotes
Funding Supported by Research to Prevent Blindness (SHE, PPL, SF), Heed Ophthalmic Foundation Fellowship (VAD); Ronald G Michels Fellowship Foundation (VAD); AOS-Knapp Fellowship (VAD).
Competing interests None.
Ethics approval Ethics approval was provided by the Duke University Medical Center Institutional Review Board (IRB # 2287.00.12ER).
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.