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| ORIGINAL ARTICLE |
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| Year : 2023 | Volume
: 11
| Issue : 1 | Page : 3-9 |
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Quality of life in patients with glaucoma using the Glaucoma Quality of Life-15 Questionnaire
Mukesh Kumar1, Shafia Parveen2, Lokesh Chauhan3
1 Department of Glaucoma, C L Gupta Eye Institute, Moradabad, Uttar Pradesh, India
2 Department of Optometry and Visual Sciences, C L Gupta Eye Institute, Moradabad, Uttar Pradesh, India
3 Department of Clinical Research, C L Gupta Eye Institute, Moradabad, Uttar Pradesh, India
| Date of Submission | 01-Jul-2022 |
| Date of Decision | 18-Nov-2022 |
| Date of Acceptance | 20-Nov-2022 |
| Date of Web Publication | 8-Feb-2023 |
Correspondence Address:
Mukesh Kumar
Department of Glaucoma, C L Gupta Eye Institute, Ram Ganga Vihar, Phase II (Ext) Moradabad - 244 001, Uttar Pradesh
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jcor.jcor_88_22
Purpose: The purpose of this study is to measure the quality of life (QoL) in patients with glaucoma using the Glaucoma QoL-15 (GQL-15) questionnaire. Methods: A cross-sectional study with a prospective enrollment of glaucoma patients was conducted. A total of 308 patients were participated in the study. Informed consent was obtained before the administration of the GQL-15 questionnaire. The QoL was assessed using an orally administered GQL-15 questionnaire. Patients' QoL was assessed based on their age, gender, visual field (VF) defect, severity of glaucoma, laterality of disease, history of previous glaucoma surgery, and the number of antiglaucoma medications (AGMs) they were taking. Participants were divided into mild, moderate, and severe glaucoma depending on the severity of VF defects using the Hodapp–Anderson–Parrish grading system. Results: A total of 308 glaucoma patients were interviewed. The mean age of participants was 57.7 ± 12.9 years; 173 (56.1%) of them were female. The average mean deviation (MD) of the patients was 7.8 ± 4.8 dB. There were 135 (43.8%) patients with mild, 122 (39.6%) with moderate, and 51 (16.6%) with severe glaucoma. In total, 114 (37%) patients had unilateral glaucoma, whereas 138 (44.4%) patients had previous glaucoma surgery. Sixty-two (22.1%) patients did not take any AGM. The correlation coefficient between VF MD and QoL was 0.7, which was significant at 0.01 level (two-tailed). Conclusion: The findings of this study demonstrated that the severity of VF defects has a negative impact on patient's QoL.
Keywords: Glaucoma, glaucomatous optic atrophy, normal-tension glaucoma, primary angle-closure glaucoma, primary open-angle glaucoma, quality of life, secondary glaucoma
How to cite this article:
Kumar M, Parveen S, Chauhan L. Quality of life in patients with glaucoma using the Glaucoma Quality of Life-15 Questionnaire. J Clin Ophthalmol Res 2023;11:3-9 |
How to cite this URL:
Kumar M, Parveen S, Chauhan L. Quality of life in patients with glaucoma using the Glaucoma Quality of Life-15 Questionnaire. J Clin Ophthalmol Res [serial online] 2023 [cited 2023 Mar 23];11:3-9. Available from: https://www.jcor.in/text.asp?2023/11/1/3/369360 |
| Introduction | |  |
Individuals with visual impairment have a negative influence on their physical and mental health. The most prevalent causes of vision impairment include cataract, glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy.[1] It was estimated that the number of glaucoma patients will reach 79.6 million by 2020.[2] In India, at least 12 million people are affected by glaucoma.[3] Glaucoma diagnosis is often delayed due to asymptomatic patients in the early stages of the disease. Many glaucoma patients consult an ophthalmologist or glaucoma specialist at a later stage when visual field (VF) loss involves central vision.
Health-related quality of life (QoL) has been continuously evolving since the 1980s to encompass all physical and mental aspects of a patient affecting health.[4],[5],[6],[7] QoL is the standard of health, comfort, and happiness experienced by an individual. A person's physical health, psychological state, personal beliefs, social relationships, and relationship to salient features of their environment can affect their QoL.[8] It is a multidimensional concept encompassing the emotional, physical, material, and social well-being of a person. Many studies have been published on the QoL of glaucoma patients.[9],[10],[11],[12],[13],[14] Measuring QoL is important in therapeutic decision-making. Glaucoma patients can have a low QoL due to treatment costs, functional incapacity, and side effects. Measuring QoL aids in determining a patient's overall well-being, visual function, and treatment satisfaction. This report intends to assess the QoL of glaucoma patients treated at a tertiary eye care institution in Moradabad, India.
| Methods | | |
This cross-sectional study with a prospective enrollment of glaucoma patients was carried out at a tertiary eye care institute using a Glaucoma QoL-15 (GQL-15) questionnaire. The study was approved by the institutional ethics committee and was conducted in accordance with the Declaration of Helsinki. Written informed consent was taken before the administration of the questionnaire. Consecutive glaucoma patients (diagnosed more than 6 months before enrollment) who were more than 18 years of age participated in the study. Patients with primary open-angle glaucoma (POAG), primary angle-closure glaucoma (PACG), normal-tension glaucoma, and secondary glaucoma were enrolled in the study. Secondary glaucoma included: patients with steroid-induced glaucoma, pigmentary glaucoma, pseudoexfoliation glaucoma, glaucoma associated with inflammation, traumatic glaucoma, neovascular glaucoma, drug-induced glaucoma, lens-induced glaucoma, and uveitic glaucoma. Patients with any other conditions (ocular diseases such as cataract, AMD, and retinal disorders) that could impair vision were excluded from the study. Patients with other diseases (e.g., systemic diseases) that could have an impact on the patient's QoL were excluded from the study. Patients who were not able to answer all questions were also excluded. All patients underwent a complete ophthalmic examination, including best-corrected Snellen visual acuity, gonioscopy, standard achromatic automated perimetry (Humphrey Field Analyzer; Carl Zeiss Meditec, Dublin, CA), and Goldmann applanation tonometry. The questionnaire was administered after clinical examinations. The questionnaire was administered by an independent study optometrist in a separate room. The interviewer was blinded to the clinical findings of the patient. The patient was classified into three groups according to the severity of VF defects using the Hodapp–Anderson–Parrish grading scale: (1) mild, an mean deviation (MD) of no worse than − 6 dB; (2) moderate, an MD of − 6 to − 12 dB; (3) severe, an MD worse than − 12 dB.[15],[16] The patient classification was done based on a better eye. Patients' QoL was assessed based on their age, gender, VF defect, severity of glaucoma, laterality of disease, history of previous glaucoma surgery, and the number of antiglaucoma medications (AGMs).
Glaucoma Quality of Life-15 Questionnaire
The QoL was assessed using the GQL-15 questionnaire developed by Nelson et al.[17],[18] It is a 15-item questionnaire designed to assess the effect of binocular VF loss on visual function. The questions are divided between four factors pertaining to visual disability: central and near vision (subscale 1: 2 items; maximum score 10), peripheral vision (subscale 2: 6 items; maximum score 30), dark adaptation and glare (subscale 3: 6 items; maximum score 30), and outdoor mobility (subscale 4: 1 item; maximum score 5). All the items in the GQL-15 are scored on a five-category difficulty scale, as follows: 1 = no difficulty, 2 = a little bit of difficulty, 3 = some difficulty, 4 = quite a lot of difficulty, and 5 = severe difficulty. The subscale score for each factor is calculated as the average of the sum of the item scores. Higher subscale scores indicate greater difficulty in performing vision-related activities and poorer QoL. The maximum summary score is 75, and higher scores indicate poorer QoL. The instrument is based on the premise that perceived visual disability (dark adaptation, disability glare, outdoor mobility tasks, and activities using peripheral vision) is significantly associated with binocular VF loss. It has good internal consistency and reliability.[10] The tool has been shown to demonstrate that difficulties in everyday life are mirrored by poor performance in a number of psychophysical tests.[18] In this study, we used summary and factor scores as measures of QoL in glaucoma patients.[19] GQL-15 has been continuously used to assess the QoL of glaucoma patients in many studies published in India.[9],[10],[13],[14] Gothwal et al. using Rasch analysis has reported that the total GQL-15 and subscale scores were valid, reliable, and possessed measurement characteristics.[10]
Statistical analysis
Statistical Package for the Social Sciences software version 23 (IBM, USA) was used for statistical analysis. The mean and standard deviation were calculated for continuous variables. The responses to questions were presented as percentage. D'Agostino-Pearson test for normal distribution was used to assess the normality of data. When data distribution was not normal, the independent sample KruskalWallis test and independent sample MannWhitney U-test were used for comparison. The Chi-square test was conducted to compare categorical variables. Reliability analysis was conducted to calculate Cronbach's alpha. A probability (P) of 0.05 or less was considered statistically significant.
| Results | | |
Demographics
A total of 308 patients diagnosed with glaucoma participated in the survey. The mean age of participants was 57.5 ± 12.4 years (range: 23–83 years). One hundred and seventy-three (56.1%) of them were female. Sixty-eight (22.1%) patients were not taking any AGM. Of the rest, 114 (37%) patients have been taking one, 90 (29.2%) patients two, and 36 (11.3%) patients three AGM. A total of 138 (44.4%) patients had a history of previous glaucoma surgery. A total of 114 (37%) patients have been diagnosed with unilateral glaucoma. There were 135 (43.8%) patients with mild, 122 (39.6%) with moderate, and 51 (16.6%) with severe glaucoma.
Quality of life score
Cronbach's alpha for GQL-15 was 0.96. Exploratory factor analysis revealed that the eigenvalue for the first factor was significantly higher than for the next factors (10.07 vs. 0.76). The first factor accounts for 67% of the total variance. The average QoL of all participants was 26.2 ± 13.2 (range: 23–75). The average QoL scores for the subscales (1) central and near vision, (2) peripheral vision, (3) glare and dark adaptation, and (4) outdoor mobility were 3.92.1, 11.15.3, 9.65.5, and 1.71.1, respectively. The average score of each question according to the severity of glaucoma is presented in [Table 1]. | Table 1: The distribution of the mean score for each question on the Glaucoma Quality Of Life-15 Questionnaire among the various glaucoma categories
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Quality of life score and VF defects (mean deviation)
The average MD was 7.8 ± 4.8 dB. The correlation coefficient between VF MD and QoL was 0.7, which was significant at 0.01 level (two-tailed) [Figure 1]. | Figure 1: Scatter plot between visual field defect (MD) and final QoL score. QoL: Quality of life, MD: Mean deviation
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Quality of life score and age of the patient
The correlation coefficient between age and final QoL score was 0.12. All participants were divided into two groups. Group 1 consists of patients over the age of 50 years, whereas Group 2 consists of patients equal to or under the age of 50 years. The average QoL score of Group 1 patients was 27.3 ± 13.8 and that of Group 2 patients was 23.1 ± 10.6. A one-way analysis of covariance did not reveal any statistically significant differences between the QoL scores of Group 1 and Group 2 when adjusted for MD (P = 0.18). A total of 12 (12/88) patients of <50 years of age and 19 (39/220) patients of more than 50 years of age belong to the severe glaucoma group. This difference was not statistically significant (P = 0.38; Chi-square test).
Quality of life score and severity of glaucoma
Patients with mild, moderate, and severe glaucoma had average QoL scores of 17.6 ± 4.1, 27.8 ± 7.4, and 50.2 ± 16.6, respectively (P ≤ 0.001, KruskalWallis test). Post hoc analysis using the Conover method for all pairwise comparisons revealed that the mean QoL score differed significantly between mild-and-moderate (P ≤ 0.001), mild-and-severe (P ≤ 0.001), and moderate-and-severe (P ≤ 0.001) glaucoma patients [Table 2]. In [Figure 2], the distribution of the final QoL score of mild, moderate, and severe glaucoma patients is presented. [Figure 3] shows the distribution of the mean QoL score (with a 95% of confidence interval) among different categories of glaucoma severity according to gender and history of glaucoma surgery. | Table 2: Comparison of the final quality of life score among categories of different variables
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 | Figure 2: Box plot showing the distribution of final QoL score among mild, moderate, and severe glaucoma patients. QoL: Quality of life
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 | Figure 3: Error bar plot showing the distribution of mean QoL score (with 95% confidence interval) among different categories of glaucoma severity according to gender and history of glaucoma surgery. QoL: Quality of life
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Quality of life and laterality of glaucoma
The average QoL score of patients with bilateral glaucoma was 28.1 ± 13.1 and that of unilateral glaucoma was 25.1 ± 13.1. The average subscale scores of bilateral and unilateral glaucoma patients are presented in [Table 3]. When adjusted for MD and age of the patient, there was no statistically significant difference in the QoL score of patients with bilateral glaucoma as compared to those with unilateral glaucoma (P = 0.42, one-way analysis of covariance). Similar results were reported for the average QoL score of subscales 1 (P = 0.62), 2 (P = 0.08), 3 (P = 0.49), and 4 (P = 0.28). | Table 3: Distribution of mean Glaucoma Quality of Life-15 subscale scores according to different categories of identified variables
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Quality of life score and gender
The average QoL score of male patients was 23.8 ± 11.9 and that of female patients was 28.1 ± 13.8. Gender-wise average subscale QoL scores are presented in [Table 3]. When adjusted for MD and age of the patient, there was no statistically significant difference in the QoL score of male patients as compared to those of female patients (P = 0.08, one-way analysis of covariance). Similar results were reported for the average QoL score of subscales 1 (P = 0.21), 2 (P = 0.07), 3 (P = 0.07), and 4 (P = 0.69). A total of 32 (32/173; 18.4%) females and 19 (19/135; 14%) males belong to the severe glaucoma group. This difference was found to be statistically significant (P = 0.012; Chi-square test).
Quality of life score and previous glaucoma surgery
The average QoL score of patients who had a history of previous glaucoma surgery was 23.3 ± 9.5 and of patients without any previous glaucoma surgery of 28.6 ± 15.2. The average QoL score of subscales 1, 2, 3, and 4 among patients with previous glaucoma surgery and without previous glaucoma surgery are presented in [Table 3]. There was no statistically significant difference between the QoL score of the patient who had undergone previous glaucoma surgery as compared to those with no history of glaucoma surgery when adjusted for MD and age of the patient (P = 0.34, one-way analysis of covariance). Similar results were reported for the average QoL score of subscales 1 (P = 0.13), 2 (P = 0.08), 3 (P = 0.34), and 4 (P = 0.18).
Quality of life score and antiglaucoma medication
The average QoL score of patients who have been not taking any AGM was 25.4 ± 14.3, on one AGM was 26.8 ± 10.1, on two AGMs was 24.4 ± 13.1, and on three AGMs was 30.6 ± 18.7 [Table 2]. There was no statistically significant difference between the QoL score of the patient who was not taking any AGM and patient who were on one, two, or three AGM, when adjusted for MD and age of the patient (P = 0.63, one-way analysis of covariance).
Quality of life score and type of glaucoma (primary open-angle glaucoma/primary angle-closure glaucoma)
The distribution of type of glaucoma among study participants is presented in [Table 4]. Among all, there were 36 patients of bilateral POAG and 50 patients of bilateral PACG. The average QoL score of POAG patients was 29.6 ± 16.9 and that of PACG patients was 23.2 ± 9.2 (P = 0.045, independent t-test). When adjusted for MD and age of the patient, there was no statistically significant difference in the QoL score of male patients as compared to those of female patients (P = 0.1, one-way analysis of covariance). | Table 4: Cross-tabulation of type of glaucoma between the right and left eye
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| Discussion | | |
The GQL-15 questionnaire was used in this study due to its good internal consistency and reliability. It is user-friendly in clinical settings and, on average, takes only 5 min to be administered. This questionnaire has been extensively used worldwide, including in India. It has been translated into many languages, such as Siberian,[20] Persian,[21] German,[22] and Chinese.[23] A meta-analysis by Wang et al. reported that patients with mild, moderate, and severe glaucoma exhibited significantly poorer QoL relative to that observed in patients without glaucoma.[19] The value of Cronbach's alpha in our study indicates a high level of internal consistency. There was no effect on the overall value of Cronbach's alpha even if we removed each question one by one. This indicates that there was no need to remove or modify any questions from the GOL-15 questionnaire for our study population. Factor analysis also revealed the unidimensionality of the questionnaire.
In our study, the average GQL-15 score of all glaucoma patients was 26.2 ± 13.2. This score was similar to the QoL score reported by previous studies (using the GQL-15 questionnaire) from Siberia (20.68),[20] China (28.79),[23] and Iran (26.8 for severe glaucoma).[21] However, studies from Germany (77.3) and Ethiopia (41.2 for mild glaucoma) reported significantly higher QoL scores.[22],[24] In our study, the average QoL score of patients diagnosed with mild glaucoma was significantly lower than that of patients with moderate or severe glaucoma. A higher QoL score corresponds to a worse QoL. The QoL score of patients with severe glaucoma was worse. Previous studies by Goldberg et al.[17] and Onakoya et al.[25] also reported statistically different average GQL-15 QoL scores between mild, moderate, and severe glaucoma patients. Kumar et al. reported a significant difference in QoL scores between moderate and severe glaucoma patients.[9] Nelson et al. have not reported any statistical difference between QoL scores of mild and moderate glaucoma patients.[18]
Female patients have higher QoL scores than male patients. Furthermore, the QoL score of every subscale was higher for females. Although this difference was not statistically significant when adjusted for VF defects and patient age. In our study, there were more severe glaucoma patients among females as compared to males. This could also be one reason why female patients had higher QoL scores. The patient's age was not correlated with the final QOL score. The QoL score for dark adaptation and glare was higher in patients who were more than 50 years of age. Older patients face more difficulty in performing their routine during the night. The distribution of severity of glaucoma among these groups was not found to be statistically significant. Alqudah et al. also reported an association of age and gender with the QoL of early glaucoma patients.[26]
In our study, VF defects were found to be significant predictors of the final QoL of a glaucoma patient. The average QoL score of patients who had a history of previous glaucoma surgery was lower than that of patients without a history of previous glaucoma surgery. When the difference was adjusted for the VF defect and age of the glaucoma patient, it was no longer significant. Furthermore, the QoL score of patients who had undergone glaucoma surgery was lower in subscales 1 and 2. This indicates that patients without glaucoma surgery felt significantly more compromised in their central and peripheral vision. However, it has no significant effect on dark adaptation and glare. A few previous studies have reported that there was no significant difference in average QoL score between medically and surgically treated groups.[27],[28] Hirooka et al. also reported significant improvement in QoL after the patients underwent combined cataract and glaucoma filtration surgery.[29] Changes in QoL after glaucoma surgery are important.
The average QoL score of bilateral glaucoma was higher as compared to unilateral glaucoma. Patients with bilateral glaucoma have been more concerned about this disease. It has also been reported in previous studies that bilateral glaucoma affects the QoL more than unilateral disease.[30],[31] Rulli et al. reported that bilateral VF defects have been associated with the deterioration of vision-related patient QoL.[32] The QoL score of patients who were on three AGMs was higher compared to others, but the difference was not significant. The use of AGMs has been associated with dry eye syndrome, and dry eye syndrome itself has a negative impact on patients' QoL.[33] However, GQL-15 has no questions regarding the AGMs and their impact on QoL.
There are some limitations to this study. Patients with the same grade of the disease may rate their QoL differently. Still, these comparisons are helpful in understanding the impact of this disease on the overall QoL of glaucoma patients in the study area. The questionnaire was orally administered and was not translated into the local language. However, to control the bias, all the questions were asked by a single trained interviewer in the local language of the participants. There was no control group. The questionnaire was administered only to glaucoma patients. However, the results are well compared with the previously published studies.
| Conclusion | | |
GQL-15 appeared reliable in the assessment of QoL in this study population. Summary scores differed significantly among patients with mild, moderate, and severe glaucoma demonstrating a trend of poorer QoL with increasing disease severity. This highlights the importance of early glaucoma diagnosis in preserving QoL. The patient VF defects and previous glaucoma surgery were identified as significant predictors of their QoL. There is a need to conduct longitudinal studies to evaluate possible changes in vision-related QoL of glaucoma patients.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4]
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