1
Cicendo Eye Hospital National Eye Center Bandung ABSTRACT
Introduction
Glaucoma management aims not only to maintain visual function, but also the patients’
quality of life (QOL). A reliable visual field assessment is needed to monitor progression of glaucoma, as well as assessing visual disability. Visual Field Index (VFI) as the latest global index offers a practical summary of visual field status and has the advantage of not being affected by cataract and focuses on the central visual field.
Objective
To determine the correlation between visual field deterioration using VFI and the QOL of glaucoma patients using National Eye Institute Visual Function Questionnaire-25 (NEI- VFQ-25).
Method
We found 72 subjects who were diagnosed primary open or closed angle glaucoma on both eyes and whose visual fields were unaffected by other condition besides glaucoma. All subjects had reliable 24-2 or 30-2 visual field test within last 6 months and had been interviewed with NEI-VFQ-25 Indonesian version. Correlations were calculated between the better eye’s VFI and NEI-VFQ-25 subscales. A single linear regression analysis was utilized between composite score and better eye’s VFI.
Results
Modest correlations were found between VFI and majority of NEI-VFQ subscales: general vision, near acuity, distance acuity, social function, mental health, role difficulties, and dependency. Weak correlations were found between VFI and ocular pain, and general health. Strong correlations were found between VFI and composite scores (r=0.746).
Conclusions
A strong positive correlation was found between visual field defect as represented by VFI and with QOL in glaucoma patients.
Keyword: visual field, glaucoma, visual field index, quality of life
INTRODUCTION
Glaucoma is a chronic and progressive optic neuropathy.
Blindness due to glaucoma is ranked
third worldwide. The International Agency for the Prevention of Blindness (IAPB) states that in 2015 there were 253 million people with
visual impairment, with 36 million of them are blind. From these numbers, about 2.78% of visual impairment and 1.91% of blindness caused by glaucoma. Blindness on both eyes is estimated to occur in 5.9 million people with open-angle glaucoma and 5.3 million people with closed-angle glaucoma.1-5
Glaucoma patients need treatment and clinical evaluation for life, therefore the management of glaucoma not only to maintain visual function, but also the quality of life.
The use of vision-specific questionnaire is more recommended than generic questionnaire in evaluating the correlation of quality of life with visual field in glauoma.
Although glaucoma specific questionnaires are available such as Glaucoma Quality of Life-15 (GQL- 15), NEI-VFQ-25 has better correlation and reliability than GQL- 15. The NEI-VFQ-25 questionnaire has also been used in assessing the quality of life of glaucoma patients in multicentered studies with large populations.6-9
Most study regarding the quality of life of glaucoma patients and decreased visual field use the global index Mean Deviation (MD).
Although MD can reliably evaluate field deterioration, it is not sensitive in identifying focal depression and
affected by cataracts. Decreased visual field due to cataracts or glaucoma needs to be distinguished, because both conditions are age- related and often occur together. In recent years, VFI was developed for calculating the rate of glaucoma progression. Bengtsson and Heijl reported that VFI was more accurate in detecting central visual field abnormalities without being affected by cataracts. Sawada et al compared the correlation of VFI and MD with the quality of life in glaucoma patients in Japan using the NEI-VFQ-25 instrument. The result is VFI has better correlation than MD.
Unfortunately studies of quality of life for glaucoma patients using VFI parameters are still minimal. Until today, little information has been obtained regarding the quality of life of glaucoma patients in Indonesia, as well as its relationship with the decreased visual field. Therefore this study aims to evaluate the correlation between visual field deterioration based on VFI, with the quality of life in glaucoma patients.10-15
SUBJECTS AND METHODS This study is an analytic cross- sectional study conducted at the Glaucoma Unit of the National Eye Center Cicendo Eye Hospital
Bandung in March-May 2020. The inclusion criteria were subjects aged 40-80 years, had been diagnosed primary glaucoma (open angle or closed angle) in both eyes, and have reliable perimetry in the past 6 months, or can undergo Humphrey SITA Standard 30-2 or 24-2 visual field examination, at least in one eye.
The exclusion criteria are patients with best corrected visual acuity less than 1/60, had a history of intraocular surgery within 3 months, patients with acute angle closure glaucoma, ocular inflammation such as blepharitis, conjunctivitis, keratitis, and uveitis, corneal abnormalities that affect visual axis such as keratopathy, patients with ocular pathology of the retina or optic nerve, and who have known comorbid diseases that affect quality of life such as mental disorders, dementia, end-stage renal failure, stroke and malignancy.
Patients who had speech impairment or unable to speak Indonesian, and were not cooperative during interview were also excluded.
After obtaining approval from institutional ethics board, due to Corona Virus pandemic situation, subjects were enlisted in two ways, consecutive visit at Glaucoma clinic and based on medical records. Data search through medical records was
performed using the 10th Revision of the International Statistical Classification of Disease and Related Health Problems (ICD-10) code with diagnosis of primary open angle glaucoma (code H40.1) and primary angle closure glaucoma (code H40.2) who have undergone Humphrey's perimetry examination in November 2019 - May 2020. Patients who met the inclusion criteria were contacted via telephone, then given explanation of the procedure and benefits of the study.
Data collection includes the patient's name, gender, age, residential address, and contact number. The socioeconomic status of the patient including education level, occupation, and income level was also recorded. Data related to glaucoma including diagnosis and type of glaucoma, intraocular pressure, history of anti-glaucoma medications and eye surgery. Systemic disease and treatment were also recorded. Visual acuity, anterior segment examination using slit lamp biomicroscopy, intraocular pressure measurement with Goldmann aplanation tonometer, and evaluation of optic nerve with Digital Wide Field lens or 78 D lens were done. For subjects who could not visit the glaucoma clinic, clinical
examination data were taken from the latest visit.
Perimetry data used were Humphrey Visual Field 24-2 or 30-2 SITA Standard strategy with reliability index fixation losses <20%, false-negative and false-positive errors <15%. The VFI values in better eye were obtained for correlation analysis with the NEI-VFQ-25 questionnaire.
The interview method was chosen with the aim that all patients had same perception for each question. All scores from each subscale of each respondent will be added up and averaged to become a composite score according to the NEI-VFQ-25 manual.
Data normality were analyzed using the Kolmogorov-Smirnov test.
The statistical correlation between numerical data used the Spearman correlation test. The correlation strength (r) based on the Guillford criteria are: 0.0 - <0.2 = very weak or negligible; 0,2 - <0,4 = weak; 0.4 -
<0.7 = moderate; 0.7 - <0.9 = strong.
Linear regression analysis was used to
assess the correlation strength and direction (positive or negative) between the VFI score and the composite score.
RESULTS
The total medical record search results were 349 datas, but the data that fit the inclusion criteria were 102 datas. From these data, 28 subjects could not be contacted via telephone, and 2 subjects were excluded because uncooperative during interview. Total of 72 subjects met the inclusion criteria, of which 18 subjects were obtained from Glaucoma unit follow up visits, while 54 subjects were obtained from medical records.
Table 1 shows similar percentage between male subjects (48.6%) and women (51.4%). The mean age of participants was 63.28 years. Majority of patients had moderate level of education (54.2%), and unemployed (66.7%). Patients with low incomes were 33.3%, while those with high and very high incomes were 25%.
Table 1. Demographic Social Characteristics of Research Subjects
Variabel Total (n= 72) Percentage (%)
Gender
Male 35 48.6
Female 37 51.4
Age(Years)
Mean±SD 63.28±9.085
Rentang (minimal-maksimal) 41.00-80.00
Education Level
Low 25 34.7
Moderate 39 54.2
High 8 11.1
Occupation
Unemployed 48 66.7
Employee 11 15.3
Entrepreneur 12 16.7
Other 1 1.4
Income Level
Low 24 33.3
Moderate 12 16.7
High 18 25
Very High 18 25
Notes:SD = Standard Deviation
Subjects were primary open angle glaucoma patients (56.9%) and primary angle closure glaucoma patients (43.1%). Most subjects had good vision, 54.2% included in the category of no visual impairment and
23.6% mild visual impairment (table 2). The mean intraocular pressure were under control (<21 mmHg). The median value of VFI in better the eye is 78.50%.
Table 2. Clinical Characteristics of Research Subjects
Variable n=72 subjects , n (%)
Primary Glaucoma Types
Open Angle 41(56.9)
Closed Angle 31(43.1)
Visual Acuity (Better eye)
Good (≥ 6/12) 39 (54.2)
Mild (6/18 - < 6/12) 17 (23.6)
Moderate (6/60 - < 6/18) 12 (16.7)
Severe (3/60 - < 6/60) 4 (5.5)
Blindness (NLP - < 3/60) 0
Intraocular Pressure Right Eye
Mean±SD 18.13±7.394
Left Eye
Mean±SD 15.67±4.876
Visual Field Index (Better Eye)
Median 78.50%
Range (min-max) 2.00-97.00%
Mean Deviation (Better Eye)
>-6 dB 17 (23.6)
6-12 dB 22 (30.6)
< - 12 dB 33 (45.8)
Notes:SD = Standard Deviation.. NLP: No Light Perception
The result of Spearman correlation test between the VFI variables with each subscale variable and the composite score from the NEI-VFQ- 25 questionnaire had a value of r = 0.251 - 0.746 (p <0.05). The color vision subscale was not analyzed because the response of subjects who responded to color vision was less than 50% (24 patients). The
correlation between the two variables was conducted using the Guilford criteria. Weak correlation was found between VFI and the general health subscale and eye pain. Strong correlation was found between VFI and the peripheral vision subscale (r = 0.70) and the composite score (r = 0.746), while other subscales had moderate correlation (table 3).
Table 3. Correlation Analysis of Visual Field Index (VFI) with Composite Score and Quality of Life Subscale using the NEI-VFQ-25 Questionnaire
A positive correlation was found between VFI score and NEI-VFQ-25 composite score, with a linear regression equation y = 0.484x + 38.034. The single linear regression
line in Figure 1 shows that the higher the Visual Field Index value, the higher the quality of life score on the NEI-VFQ-25 questionnaire.
Variabel r Nilai p
VFI with Composite Score 0.746 0.0001*
VFI with General Health 0.251 0.033*
VFI with General Vision 0.683 0.0001*
VFI with Eye pain 0.378 0.0001*
VFI with Near Vision 0.605 0.0001*
VFI with Distance vision 0.683 0.0001*
VFI with Social Function 0.638 0.0001*
VFI with Mental Health 0.666 0.0001*
VFI with Role limitation 0.581 0.0001*
VFI with Dependency 0.607 0.0001*
VFI with Driving 0.633 0.001*
VFI with Color Vision Tidak dianalisis
VFI with Peripheral Vision 0.700 0.0001*
Note: the significance value is p <0.05. The sign * indicates statistical significance, r: correlation coefficient using the Spearman correlation test.
0.0 20.0 40.0 60.0 80.0 100.0 120.0
0 20 40 60 80 100 120
Composit score
Visual Field Index score y= 0,484x + 38,034
Figure 1. Scatter plot correlation of quality of life scores with Visual Field Index
Figure 2 shows an overview of the results of each subscale score and composite score of the NEI-VFQ 25 questionnaire. A score of 0 on the NEI-VFQ-25 questionnaire is the worst value, while a score of 100 indicates no visual impairment. The
highest score in this study is the social function subscale (median 87.50), while the lowest score is the driving subscale (median 45.83). The mean composite score of the NEI-VFQ-25 questionnaire from all subjects in this study was 67.49.
Figure 2. Average scores of each subscale and composite scores of all patients DISCUSSION
This study included 72 patients with age range of 41 to 80 years. The global glaucoma prevalence in the population of 40-80 years is 3.54%.3 The prevalence of primary angle closure glaucoma varies depending on race and ethnicity. The risk of primary glaucoma increases with age. In primary open-angle glaucoma, people over 70 years have a risk 3-8 times higher than the age of 40 years.16
Age, gender, occupation, environment, ethnicity, and culture can influence the results of quantitative assessments of quality of life. The average composite score in this study was 67.49. This value is lower than similar quality of life studies in patients with open-angle primary glaucoma in Japan (mean composite score 78.3).14 Most patients in this study were not of productive age (average age of 63.28 years), had a history of moderate education level,
and had low income. Glaucoma patients with a younger age and higher education are reported to have a higher quality of life score.17-19 The general health subscale in the NEI-VFQ-25 questionnaire assesses an individual's perception of his general health as a supporting part of vision-related quality of life. In this study the general health subscale is decreased (score 50). Sawada defines the NEI-VFQ-25 score subscale as low if a score below 59.17 Open angle primary glaucoma patients have lower general health scores than those without glaucoma using the generic health questionnaire SF-36.7 Further studies by Sawada and Madonna using NEI-VFQ-25 questionnaire found a significant but weak correlation between general health and VFI (r = 0.197 and r = 0.201).14, 20 Similar results were also found in this study (r = 0.251). Most of the patients (45.8%) in this study had severe glaucoma (MD > 12 dB). McKean- Cowdin stated that the decline in quality of life in terms of general health can occur even in patients with mild visual field loss (6 dB <MD <2 dB).
There is a different individual perceptions between people with glaucoma and non-glaucoma regarding vision-related quality of life. This individual perception is generally assessed through the eye
health subscale score. This study shows a moderate correlation (r = 0.683) between the decrease in visual field with the eye health subscale. The median eye health score for all subjects in this study was 60. This score was slightly lower than the study by Sawada (score 66.6) and Riva (score 65.8).14, 22 Loss of visual field, decreased visual acuity, and complex treatment history in glaucoma correlated with the patients’
perception of their eye health.
A weak correlation (r = 0.378) for the eye pain subscale is explainable because patients with eye pain such as acute glaucoma have been excluded.
Chun et al found that gender may affect on eye pain complaints. Women generally had lower eye pain scores than male patients.23 In this study the mean eye pain score in male patients was 78.6 while in women was 72.3.
The median eye pain subscale score in this study was 75. Although there was a decrease in score, 67% of patients in this study responded to pain that was mild and did not interfere with daily activities. In glaucoma with severe visual field loss, lower eye pain scores are also associated with poorer vision in the eyes.23 Controlled intraocular pressure showed that complaints of eye pain from most patients did not originate from raised intraocular pressure, but may come from ocular
surface conditions. Ocular surface disease has a prevalence of 15% in individuals over the age of 65 years and increased to 59% in patients with glaucoma.24
Psychosocial conditions assessed in NEI-VFQ-25 questionnaire include the mental health subscale, social functioning, role limitations, and dependency. These four subscales have a moderate correlation. Social function is the subscale with the most minimal reduction (median score of 87.5). There may be ethnic and cultural influences related to such outcomes. Correlation results between decreased visual field with the incidence of depression in people with glaucoma also still vary.25,26 The effect of direct visual field decrease on limitations in driving, fear of falling, and poor balance mentioned contribute to the relationship between glaucoma and depression.7 Prevalence of anxiety and depression in patients with primary open-angle glaucoma was evaluated in a case-control study using the Hospital Anxiety and Depression Scale (HADS). The prevalence of patients with anxiety (13.0%) and depression (10.9%) is significantly higher than in the control group (7% and 5.2%).27 The study also states that glaucoma patients with a younger age tend to have more anxiety than with older ones.
However, many factors needed to be
explored further in assessing the correlation between objective measurements with mental health conditions. The mental health subscale can be more influenced by the patient's individual perception of his vision than by objective clinical measurements. In addition, the condition of depression itself can cause worse response to the questionnaire questions.
This study shows a moderate correlation (r = 0.633) between the value of VFI and driving. The Salisbury Eye Evaluation study found a strong correlation between the visual field with nighttime driving, even after adjusting for contrast sensitivity factors.28 The Los Angeles Latino Eye Study reports that moderate to severe bilateral visual field loss has a significant effect on driving, whereas severe unilateral vision has minimal effect on driving ability.29 Several studies have shown that glaucoma patients tend to change their driving habits as a result of the visual perception. Habits changes include stop driving at night, reducing the frequency and duration of driving, and stop driving in unfamiliar places.
Compared with individuals without glaucoma, the decision to stop driving is significantly more common in patients diagnosed with bilateral glaucoma than unilateral. Patients with bilateral glaucoma were three
times more likely to stop driving than those without glaucoma.30 In this study where all subjects had bilateral glaucoma, 42% of subjects had stopped driving after being diagnosed with glaucoma.
The subjects' responses to the color vision subscale differed from the results of the other subscales The NEI-VFQ-25 questionnaire contains questions in the form of the patient's ability to choose and match clothing.
Only 33% of patients still interested in matching clothes, so the results of this score could not describe the assessment of all subjects for color vision.
This study shows a strong correlation (r = 0.70) between VFI and peripheral field of view.
Mobilization is one of the daily activities that is disrupted because of visual field abnormalities in glaucoma.
Positive and strong correlation was shown between better eye VFI with a composite score of quality of life using the NEI-VFQ-25 questionnaire (r = 0.746). Worsening of visual field, as seen from the lower VFI score, causing lower quality of life score on the NEI-VFQ-25 questionnaire. This indicates that VFI can potentially be used as an indirect measure in monitoring visual disability in the management of glaucoma patients.
This finding also shows that clinicians
should not only pay attention to poorer eye, but also to better eyes to prevent glaucoma worsening and result in decreased quality of life.
There are several limitations in this study, including the potential for reporting bias due to interviewer differences. However both interviewers have minimized this by conducting the interview method as much as possible in accordance with the sentences listed in the interviewer's NEI-VFQ-25 questionnaire format. Another limitation of this study is not analyzing the influence of socioeconomic factors and psychological conditions. Objective measurements of the contrast sensitivity, glare and stereoacuity was also not done. Individual subjectivity factors may make the results of the questionnaire do not truly reflect the actual disturbance experienced by patients in their daily activities. The use of performance-based tests may provide a more objective representation of decreased visual field experienced by people with glaucoma in their daily activities.
CONCLUSION
Positive and strong correlation was found between visual field index scores with the quality of life in glaucoma patients using the NEI- VFQ-25 questionnaire.
REFERENCES
1. Saunders, L. J., Medeiros, F. A dkk. What rates of glaucoma progression are clinically significant? Expert Review of Ophthalmology. 2016;11(3):
227–234
2. Ichhpujani P. Kumar S. What’s New in Pathogenesis of Glaucoma. In: Glaucoma. First Edition. Singapore:
Springer;2019: p.1-2
3. Tham, Y.C., Li, X dkk. Global Prevalence of Glaucoma and Projections of Glaucoma Burden through 2040. Ophthalmology.
2014; 121(11): 2081–90.
4. Balantrapu T. Latest Global Blindness & Visual Impairment prevalence figures published in Lancet [document on the Internet]. IAPB; 2017 [cited 2020 January]. Diunduh dari:
http:/
https://www.iapb.org/news/latest global-blindness-vi-prevalence- figures published-lancet/
5. Pascolini, D., & Mariotti, S. P.
Global estimates of visual impairment: 2010. British Journal of Ophthalmology.2011;
96(5): 614–618.
6. European Glaucoma Society.
Terminology and guidelines for glaucoma. 4thed. Savona, Italy:
DOGMA; 2014.
7. Quaranta, L., Riva, I. dkk.
Quality of Life in Glaucoma: A Review of the Literature.
Advances in Therapy. 2016;
33(6);959–81.
8. Mangione CM, Lee PP, Gutierrez PR, et al; National Eye Institute Visual Function Questionnaire Field Test Investigators.
Development of the 25-item National Eye Institute visual function questionnaire. Arch Ophthalmol 2001;119(7):1050–8 9. Kumar, S., Thakur S, Ichhpujani P. The impact of primary open- angle glaucoma: Comparison of vision-specific (National Eye Institute Visual Function Questionnaire-25) and disease- specific (Glaucoma Quality of Life-15 and Viswanathan 10) patient-reported outcome (PRO) instruments. Indian J Ophthalmol. 2019; 67(1): 83–88.
10. Heijl A; Vincent M P; Bengtsson B. Effective Perimetry. Fourth Edition. Dublin, CA : Carl Zeiss Meditec Inc.; 2012:pp.1-22, 45- 72
11. Shaarawy TM, Sherwood MB, dkk. Glaucoma Medical Diagnosis and Therapy. Second Edition. Philadelphia: Elsevier;
2015: pp.128-9, 272-3, 510-9 12. Bengtsson, B., & Heijl, A. A
Visual Field Index for Calculation of Glaucoma Rate of Progression. American Journal of Ophthalmology.2008;145(2):
343–353.
13. Peters, D., Heijl, A., Brenner, L.,
& Bengtsson, B. Visual impairment and vision-related quality of life in the Early Manifest Glaucoma Trial after 20 years of follow-up. Acta Ophthalmologica.2015;93(8);
745–752
14. Sawada, H., Fukuchi, T., & Abe, H. Evaluation of the relationship between quality of vision and the visual function index in Japanese glaucoma patients. Graefe’s Archive for Clinical and Experimental
Ophthalmology.2011; 249(11):
1721–1727
15. Rosalina D, Harijo W. Visual Field Abnormality and Quality of Life of Patient with Primary Open Angle Glaucoma. Jurnal Oftalmologi Indonesia. 2011;
7(5): 175−180
16. American Academy of Ophthalmology. Section 10:
Glaucoma: Introduction to Glaucoma: Terminology, Epidemiology, and Heredity. In : Basic and Clinical Science Course. San Fransisco: American Academy of Ophtalmology;
2019.
17. Medeiros, F. A., Gracitelli, C. P.
B., et al. Longitudinal Changes in Quality of Life and Rates of Progressive Visual Field Loss in
Glaucoma Patients.
Ophthalmology,2015;122(2):293 –301.
18. Sawada H, Fukuchi, T., &
Haruki, A. Evaluation of the relationship between quality of vision and visual function in Japanese glaucoma patients.
Clinical Ophthalmology, Clinical Ophthalmology 2011:5:259–67 19. Kuo, Y.S., Liu, C. J, et al. Impact
of socioeconomic status on vision-related
quality of life in primary open-
angle glaucoma.
Eye.2017;31(10):1480–7.2010 [diunduh 17 Januari 2020].
Tersedia dari:
https://onlinelibrary.wiley.com/d oi/abs/10.1111/j.1755-
3768.2010.4356.
20. Madonna R.J., D. Rutner, L.
Nehmad. Investigating the Association between Visual Field Index Scores and NEI VFQ-25 Scores in Glaucoma Patients. Investigative Ophthalmology & Visual Science [abstract]. 2019;50:3771 [diunduh 17 Januari 2020].
Tersedia dari:
https://iovs.arvojournals.org/arti cle.aspx?articleid=2366157 21. McKean-Cowdin, R., Varma, R.,
et al. Severity of Visual Field Loss and
Health-related Quality of Life.
American Journal of Ophthalmology, 2007;143(6):
1013–23
22. Riva, I., Legramandi, L., dkk.
Vision-related quality of life and symptom
perception change over time in newly-diagnosed primary open angle glaucoma patients.
Scientific Reports. 2019;9(1) 23. Chun, Y. S., Sung, K. R., Park, C.
K., et al. Factors influencing visionrelated
quality of life according to glaucoma severity. Acta Ophthalmologica.
2019;97(2):216-24.
24. Leung EW, Medeiros FA, Weinreb RN. Prevalence of ocular surface disease in glaucoma patients. J Glaucoma.
2008;17:350–5.
25. Skalicky, S. E., Martin, K. R, dkk. Cataract and quality of life in patients
with glaucoma. Clinical &
Experimental Ophthalmology.
2014;43(4), 335–41.
26. Jampel HD, Frick KD, Janz NK, et al. Depression and mood indicators in newly diagnosed glaucoma patients. Am J Ophthalmol 2007;144(2):238- 44.
27. Mabuchi F, Yoshimura K, Kashiwagi K, et al. High prevalence of anxiety and depression in patients with primary open-angle glaucoma. J Glaucoma.2008;17:552–7.
28. Freeman EE, Munoz B, West SK, Jampel HD, Friedman DS.
Glaucoma and quality of life: the Salisbury eye evaluation.
Ophthalmology. 2008;115:233–
8.
29. McKean-Cowdin R, Wang Y dkk. Impact of Visual Field Loss on Health-Related Quality of Life in Glaucoma. The Los Angeles Latino Eye Study.
Ophthalmology.2008; 115:941-8 30. Freeman EE, Munoz B, Turano KA, West SK. Measures of visual function and their association with driving modification in older adults.
Invest Ophthalmol Vis Sci.
2006;47:514–20.