Impact of glaucoma on vision-specific quality of life in monocular glaucoma patients using the Indian vision function questionnaire

Abstract

Purpose:

To evaluate the determinants affecting the quality of life in monocular glaucoma patients using the Indian vision function questionnaire.

Methods:

In this prospective cross-sectional study, total of 196 patients were divided into two groups: cases and controls. Indian Vision Function Questionnaire (IND-VFQ) was administered and analyzed. One hundred twenty-nine (58.6%) patients who had lost their vision in one eye due to glaucoma were included as cases and 67 (30.4%) patients who had lost their vision due to other causes were taken as controls.

Results:

Median composite score of subscales was 54.62 (29.7–74.7) in group 1 and 45.38 (23.7–76.7) in group 2. The psychosocial impact scale was the most affected scale, the median scores were 33.02 (0 to 60.0) and 19.07 (0 to 53.0) in groups 1 and 2, respectively. Among all dimensions of IND-VFQ, the highest score was for color vision 100.0 (0–100.0) and 100.0 (0–100.0), and the lowest median score was found in mental health and dependency in both the groups. Multiple linear regression analysis demonstrated that visual acuity was associated with a low score (P < 0.001). Female gender was significantly associated with the overall score in the univariate model (P = 0.006).

Conclusion:

Monocular glaucoma patients have a poor general and vision-related quality of life. Depression associated with monocularity and the perception of dependency and being a burden on their family members greatly impacted the mental health of the participants.

The term “quality of life” (QoL) is a broad concept incorporating the patient’s perspective of health, it also reflects the gap between a person’s expectations and their present status.[1] QoL was introduced to ophthalmology in the 1980s as an evaluation. Compared with the general QoL evaluation tools, vision-related QoL measurements have been widely accepted as they specifically reflect the impact of visual function impairment on the individual.[2] Maximizing a patient’s QoL has been one of the main goals of glaucoma treatment[3] because vision-related QoL is reduced by glaucoma.[4,5] In 1996, Zimmerman et al.[6] challenged the current guidelines for the treatment of glaucoma focusing attention away from clinical indicators to the quality of life. Outcome assessment has become increasingly important as a critical measure for the treatment and management of medical conditions, and Zimmerman et al.[6] and Lee et al[7] have highlighted the need for patient-centered care in glaucoma.[8]

A myriad of patient-reported outcomes (PROs, commonly referred to as questionnaires or instruments) has been developed in the field of ophthalmology over the past 20 to 30 years.[9] The National Eye Institute Visual Functioning Questionnaire (NEI-VFQ), developed by Mangione et al.[10] is among the most popular questionnaires. It has been developed predominantly for a Western population and thus the content may be perceived as irrelevant by those in developing countries such as India. In contrast, the Indian Vision Function Questionnaire (IND-VFQ) was specifically developed for the Indian population.[11] During the development of IND-VFQ, recruited patients were of cataract, glaucoma, and retinal conditions (diabetic retinopathy and age-related macular degeneration) in methodology, thus it is validated for our patient population.[12] Some previous studies have indicated that conventional clinical measures such as visual acuity (VA) and visual field assessments failed to fully capture the picture of visual disability on daily visual functioning and on abilities to perform activities of daily living that are valued by patients. Thus, questionnaires will be helpful to better evaluate visual and general health disabilities.[13]

Glaucoma impacts individuals at various levels, it reduces the ability to carry out self-care activities,[14] increases dependence,[15] depression,[16] falls,[17] traffic accidents,[18,19] risk of fracture,[20,21] and mortality.[13,14] A few studies have evaluated the functional impact and recovery from acquired monocular vision and sampled a more diverse population of monocular patients and employed custom-made rather than validated questionnaires to evaluate the function and recovery of their patients. Statistical significance was found between normal and those with monocular vision following surgery.[22-24] To date and to the best of our knowledge, no study in the literature has assessed the quality of life in monocular patients with glaucoma in the Indian population.

The primary purpose of this cross-sectional questionnaire-based study was to assess the QoL in monocular glaucoma patients with IND-VFQ and the factors affecting their QoL. The secondary purpose of our study was to compare the differences in vision-related quality of life (VRQoL) between monocular glaucoma patients and monocular vision loss due to any etiology other than glaucoma.

Methods

This was a prospective hospital-based cross-sectional study conducted in a glaucoma clinic at a tertiary eye care center in Tirunelveli, Tamil Nadu, India. The study was approved by the Institutional Ethics Committee of the hospital. It was conducted as per the tenets of the Declaration of Helsinki.

Patients, aged 40 years and above, with primary open-angle glaucoma (POAG) and primary angle closure glaucoma (PACG) on long-term drug therapy with vision loss in one eye due to glaucoma with best-corrected visual acuity (BCVA) in better eye >0.5 without any significant media opacity were taken as cases for the study. Monocular patients with vision loss due to reasons other than glaucoma were taken as control. Patients with suspected glaucoma, bilaterally blind patients, patients with primary neurodegenerative diseases, macular pathology, and psychologically disturbed patients were excluded from the study.

POAG patients who had been previously diagnosed and met at least two of the following three eligibility criteria were included: intraocular pressure (IOP) consistently greater than 21 mmHg with open-angle, visual field changes associated with glaucoma, or optic nerve changes consistent with glaucoma. Angle-closure glaucoma included cases with glaucoma in association with a closed angle (iridotrabecular contact noted on gonioscopy in >270° angle) with or without peripheral anterior synechiae with elevated IOP and consistent optic disc changes.

Demographic information (age, sex, and educational background) was collected by the investigators through face-to-face interviews. Detailed clinical evaluation included slit-lamp biomicroscopy, IOP measurement using Goldmann applanation tonometry (HAAG-STREIT 900, Haag-Streit, USA), central corneal thickness using ultrasound pachymeter (Tomey SP-3000, Tomey Ltd, Japan), and gonioscopy using a 4 mirror Sussman gonio lens (Ocular Instruments Inc., Bellevue, WA).

Optic disc evaluation with a Volk 90 D lens and visual field examination was conducted using the Swedish interactive threshold algorithm (SITA) standard program of Humphrey field analyzer (Carl Zeiss Meditec Inc, Dublin, CA) using the central 24-2 strategy. The central visual field was analyzed with the 10-2 SITA standard strategy. Visual field defects were classified into mild, moderate, and severe visual field loss using mean deviation (MD) indices and a modification of the Hodapp–Parrish–Anderson classification. Mild visual field loss was defined as a mean deviation of less than or equal to −6 decibels (dB), moderate visual field loss was defined as MD greater than − 6 dB but less than −12 dB, and severe visual field defect as MD greater than −12 dB. Visual acuity was assessed with a logarithm of the minimum angle of resolution (logMAR) chart and recorded separately for each eye by a trained optometrist. Phakic eyes underwent evaluation of crystalline lens with pupillary dilatation using the lens opacity classification system II (LOCS II). All these examinations were within the routine check-up for the glaucoma patient’s follow-up visits.

Patients were then divided into two groups. Group 1 (cases) consisted of monocular patients diagnosed with POAG and PACG. Group 2 (controls) consisted of monocular patients who had lost their vision in one eye due to causes other than glaucomas such as trauma, choroidal neovascular membrane (CNVM), vitreous hemorrhage, and vein occlusion.

IND-VFQ was administered to 220 patients. Reply to the questionnaire was filled with the help of an expert clinical research associate. For the subjects with writing difficulties, the research associates stated the questions and possible answers in a neutral tone for their independent choice was recorded accurately. Twenty-four incomplete and incorrect data were excluded, and 196 complete data were included in the final analysis.

Indian vision function questionnaire

The IND-VFQ (Annexure) [Table 1] is a patient-based measure of vision-related quality of life that was developed and field tested in apex eye institutions of India.[12] Interviewer bias during the administration of the questions was taken care of, and translation and back-translation methods were used by competent bilingual translators to ensure accuracy.

Table 1.

Indian vision function questionnaire

Indian vision function questionnaire (33 items)						In the first section, I am going to ask you how much your vision problem affects you in doing your daily activities. I will read out a choice of four answers and you will choose the one you feel describes you best. If you cannot do or do not want do this activity because of vision, or other reasons, please tell me.
Please tick! the response box
Q.No	General functioning scale	Not at all	A little	Quite a bit	Cannot do this because of my sight
1	Because of your vision, how many problems do you have climbing stairs?
2	Because of your vision, how much problem do you have in making out the bumps and holes in the road when walking?
3	Because of your vision, how much problem do you have in seeing if there are animals or vehicles when walking?
4	Because of your vision, how many problems do you have in finding your way in new places?
5	Because of your vision, how much problem do you have in going to social functions such as weddings?
6	Because of your vision, how many problems do you have going out at night?
7	Because of your vision, how many problems do you have in finding your way indoors?
8	Because of your vision, how much problem do you have in seeing the steps of the bus when climbing in or out?
9	Because of your vision, how much problem do you have in recognizing people from a distance?
10	Because of your vision, how much problem do you have in recognizing the face of a person standing near you?
11	Because of your vision, how much problem do you have in locking or unlocking the door?
12	Because of your vision, how many problems do you have in doing your usual work either in the house or outside?
13	Because of your vision, how much problem do you have in doing your work up to your usual standard?
14	Because of your vision, how much problem do you have in searching for things at home?
15	Because of your vision, how much problem do you have in seeing outside in bright sunlight?
16	Because of your vision, how much problem do you have in seeing when coming into the house after being in the sunlight?
17	Because of your vision, how much problem do you have in seeing differences in colors?
18	Because of your vision, how much problem do you have in making out differences in coins or notes?
19	Because of your vision, how many problems do you have in going to the toilet?
20	Because of your vision, how much problem do you have in seeing objects that may have fallen in the food?
21	Because of your vision, how much problem do you have in seeing the level in the container when pouring?
In the next section, I am going to ask you how you feel because of your eye problem, I will read out a choice of four answers and you will choose the one you feel describes you best. Please tick! the response box
Q. N O	Psychosocial impact scale	Not at all	A little	Quite a bit	Cannot do this because of my sight
22	Because of your eye problem, do you feel frightened to go out at night?
23	Because of your eye problem, do you enjoy social functions less?
24	Because of your eye problem, do you ashamed that you cannot see?
25	Because of your eye problem, do you feel you have become a burden on others?
26	Because of your eye problem, do you feel frightened that you may lose your remaining vision?
In the next section, I am going to ask you to what extent you have the following eye problems. I will read out a choice of four answers and you will choose the one you feel describes you best. Please tick! the response box
Q. N O	Visual symptom scale	Not at all	A little	Quite a bit	Cannot do this because of my sight
27	Do you have reduced vision?
28	Are you dazzled in bright light?
29	Is your vision blurred in sunlight?
30	Does bright light hurt your eyes?
31	Do you close your eyes because of the light from vehicles?
32	Does light seem like stars?
33	Do you have blurred vision?

Scaling

The questionnaire was administered to the patients in the hospital on a routine visit. It consisted of 33 items and it was divided into three scales, which were general functioning (Q1–Q21), psychosocial impact (Q22–Q26), and visual symptoms (Q27–Q33).

The general functioning scale consisted of questions regarding the day-to-day problems faced by the patients. Questions regarding the psychological burden of the disease were noted on the psychosocial impact scale. Any symptoms related to vision were recorded on the visual symptom scale.

Responses to the general functioning scale were rated on a 5-point Likert-type scale and psychosocial and visual symptoms scales were rated on a 4-point Likert scale.

These scales were further divided into 10 subscales-general vision (GV, 3 items), difficulty with near-vision activities (NV, 7 items), difficulty with distant-vision activities (DV, 2 items), limitation of social functioning because of vision (Soc. health, 3 items), mental health problems because of vision (MH, 2 items), role limitations because of vision (LOA, 6 items), dependency on others because of vision (Dep, 1 item), difficulty with color vision (CV, 1 item), difficulty with peripheral vision (PV, 1 item), and glare disability and dark adaptation (8 items). Each subscale score was converted to a score from 0 to 100. Higher scores indicated better vision-specific QoL. The composite score is the mean score of all subscales, calculated by adding all subscales divided by the number of subscales.

Developed as an interviewer-administered questionnaire and taking an average of 20–25 min to complete, the IND-VFQ is suitable for use in populations of mixed literacy levels and short enough to keep respondent burden to a minimum.[12]

Statistical analysis

In demographic data, continuous variables are represented as mean and standard deviation (SD), and categorical variables are represented as frequency (percentage). The Chi-square test or Fisher’s exact test was used to assess the association in categorical data. The normality of the variables was verified using the Shapiro–Wilk test. IND-VFQ scores are presented as median and interquartile (IQR). The mean comparison of ocular parameters between case and control was performed using an independent t-test for normally distributed data and Mann–Whitney U test for skewed data. Linear regression analysis was used to find the factors associated with quality of life scores. All subjects were included in the model. The statistical analysis was performed by STATA 14.0 (College Station, TX, USA). P < 0.05 was considered statistically significant.

Results

A total of 196 patients, 86 (44%) female and 110 (56%) male, with 72 POAG, 57 PACG, and 67 controls, were taken for the final analysis [Fig. 1]. Demographic data of the patients are shown in Table 2. In all, 68.41% of patients were educated. The mean ages of participants were 64.7 ± 9.5 years and 62.70 ± 10.4 years in groups 1 and 2, respectively. The mean IOP in the better eye was 13.94 ± 4.2 and 14.87 ± 3.8 mmHg in groups 1 and 2, respectively, which were not statistically significant. The best-corrected median logMar VA was 0 (0 to 0.18) in group 1 and 0.18 (0 to 0.30) in group 2. The median mean deviation of Humphrey Field Analysis (HFA) in the better eye in group 1 was − 12.50 db (−20.9 to − 7.1) and in group 2 was − 8.20 db (−11.1 to − 4.1). Statistical significance was seen between the two groups in the mean deviation of the visual field of the better eye (P = 0.008). The median duration from monocular blindness to questionnaire analysis was 84 (36 to 132) months in group 1 and 60 (12 to 96) months in group 2. Family history was present in 5 (3.9%) of group 1 participants, and 29 (22.5%) had a systemic illness in the form of diabetes, hypertension, asthma, or cardiac problems. In group 2, systemic illness was present in 15 (22.4%) participants.

Figure 1.

Patient population enrolled in the study

Table 2.

Demographic and clinical characteristics of study participants

	Case	Control	Total	P
Number of subjects	129	67	196
Age, years
Mean (SD)	64.71 (9.5)	62.70 (10.4)	64.03 (9.8)	0.174b
Male gender, n (%)	69 (53.5)	41 (61.2)	110 (56.1)	0.302a
Educated, n (%)	87 (67.4)	47 (70.2)	134 (68.4)	0.699a
Duration of monocularity
Median (IQR), months	84 (36 to 132)	60 (12 to 96)	72 (24 to 120)	0.036 c
Family history, n (%)	5 (3.9)	Nil	5 (2.6)	0.168a
Systemic illness, n (%)	29 (22.5)	15 (22.4)	44 (22.4)	0.988a
Lens status, n (%)
Phakic	60 (46.5)	40 (59.7)	100 (51.0)	0.080a
Pseudophakia	69 (53.5)	27 (40.3)	96 (49.0)
IOP in the better eye, mmHg
Mean (SD)	13.94 (4.2)	14.87 (3.8)	14.26 (4.0)	0.132b
BCVA in the better eye
Mean (SD)	0.15 (0.2)	0.19 (0.3)	0.16 (0.2)	0.182c
Median (IQR)	0 (0 to 0.18)	0.18 (0 to 0.30)	0 (0 to 0.30)
MD in the better eye, dB
Median (IQR)	- 12.50(-20.9 to -7.1)	-8.20 (-11.1 to -4.1)	- 10.84 (-18.4 to -6.5)	0.008 c

SD: Standard deviation, IQR: Interquartile range, IOP: Intraocular pressure, BCVA: Best-corrected visual acuity, MD: Mean deviation, log MAR: logarithm of the minimum angle of resolution, ^aChi-square test; ^bindependent t-test; ^cMann–Whitney U test; P<0.05 statistical significant

The median scores for the general functioning scale, psychosocial impact scale, and visual symptom scale were 67.80 (41.1 to 80.8), 33.02 (0 to 60.0), and 42.04 (14.0 to 80.7), respectively. In group 1 and group 2, scores were 54.00 (32.0 to 82.0), 19.07 (0 to 53.0), and 42.05 (28.0 to 76.0), respectively. The psychosocial impact scale was the most affected scale among all other scales Table 3. Among all dimensions of IND-VFQ, the highest median score was for color vision 100 (0–100.0) and 100 (0–100.0), followed by near vision 78.57 (53.6–96.4) and 67.85 (42.1–92.8) in groups 1 and 2, respectively. The lowest median score was for mental health 0 (0–50.0) and 0 (0–33.3) and dependence 0 (0-100.0) and 0 (0–66) in groups 1 and 2, respectively. The overall median score was 54.62 (29.7–74.7) in group 1 and 45.38 (23.7–76.7) in group 2 Table 4. Best-corrected vision in the better eye was found to be an important factor affecting the QoL (P < 0.001). If VA gets worse in the better eye, then the overall score decreases by 40.7 units. Female gender was significantly associated with an overall score in the univariate model (β = −10.7; 95% confidence interval [CI], −18.3 to − 3.2; P = 0.006) and was not significantly associated with QoL scores while adjusting for other factors [Table 5].

Table 3.

Comparison of IND-VFQ scores of general functioning, psychosocial impact, and visual symptom scale

	Case (n=129)	Control (n=67)	P a
General functioning scale	67.80 (41.1 to 80.8)	54.00 (32.0 to 82.0)	0.252
Psychosocial impact scale	33.02 (0 to 60.0)	19.07 (0 to 53.0)	0.221
Visual symptom scale	42.04 (14.0 to 80.7)	42.05 (28.0 to 76.0)	0.888

Scores were presented in median and interquartile range (IQR) and compared using ^aMann–Whitney U test; P<0.05 statistically significant

Table 4.

Comparison of scores of subscales for IND-VFQ

IND VFQ – Subscales	Case (n=129)	Control (n=67)	P a
General vision	58.33 (25.0–83.0)	52.06 (16.7–75.0)	0.185
Near vision	78.57 (53.6–96.4)	67.85 (42.1–92.8)	0.206
Distance vision	50.00 (0–75.0)	50.00 (0–87.5)	0.992
Social function limitation	50.00 (0–100.0)	50.00 (0–100.0)	0.676
Mental health	0 (0–50.0)	0 (0–33.3)	0.189
Role limitation	59.06 (33.3–83.0)	50.00 (33.3–72.2)	0.135
Dependency	0 (0–100.0)	0 (0–66)	0.277
Color vision	100 (0–100.0)	100.00 (0–100.0)	0.821
Peripheral vision	75.00 (0–100.0)	75.00 (0–100.0)	0.470
Dark adaptation and glare	47.75 (12.5–79.1)	37.5 (8.0–70.5)	0.277
Overall score	54.62 (29.7–74.7)	45.38 (23.7–76.7)	0.367

Subscale scores were presented in median and interquartile range (IQR) and compared using ^aMann–Whitney U test; P<0.05 statistically significant

Table 5.

Factors associated with vision-related quality of life scores

	Univariate analysis		Multivariable analysis
	β (95% CI)	P	β (95% CI)	P
Age, years	0.06 (-0.3 to 0.4)	0.776	0.04 (-0.3 to 0.4)	0.831
Female gender	-10.75 (-18.3 to -3.2)	0.006	-6.03 (-13.6 to 1.6)	0.120
Educated	0.51 (-7.7 to 8.8)	0.903	0.99 (-6.7 to 8.7)	0.799
IOP, mmHg	-0.33 (-1.3 to 0.6)	0.489	-0.001 (-0.9 to 0.9)	0.998
Monocularity duration, mon	0.07 (0.01 to 0.1)	0.008	0.04 (-0.01 to 0.1)	0.139
BCVA, logMAR	-45.4 (-60.6 to -30.2)	<0.001	-40.66 (-56.5 to -24.8)	<0.001
Controls	-3.09 (-11.2 to 5.0)	0.452	-1.14 (-8.8 to 6.5)	0.771

IOP: Intraocular pressure, BCVA: Best-corrected visual acuity, β-regression coefficient, CI: Confidence interval, P<0.05 statistical significant

Discussion

QoL is an important factor in understanding the impact of a disease and evaluating the effectiveness of healthcare interventions.[25] To understand the effect of a disease on a patient’s QoL, it is important to evaluate the importance of symptoms and disabilities.

Our study shows that the score for the mental health and dependency subscale was the lowest, suggesting that these factors were the most affected. A study conducted by Ji Min Ahn et al. on the Korean population showed that anxiety and depression were the two most commonly encountered disorders in anophthalmic patients.[24] These findings were similar to those of our study. Skalicky et al [26] reported that depression was more prevalent with increasing severity in glaucoma, in patients aged 70–79 years using the Nelson Glaucoma Severity Scale and the Geriatric Depression Scale-15 questionnaire, and that older age was a risk factor for depression. In our study, not only was the average age group 64 years but also the patients were monocular, which increased the prevalence of depression among our patients, correlating with previous studies.

Half of our study patients, especially those with glaucoma, revealed that they did not enjoy social functions and avoided going to them because of their eye problems. Studies regarding the biopsychosocial profiles of ophthalmic patients were performed in Brazil in 2006 and 2008.[27,28] A common finding between these two studies and our study was that monocular patients become increasingly shy in their social relationships because of their disability. The loss of an eye, regardless of whether it is due to a serious disease or injury, can disturb a patient’s life.

Multiple linear regression analysis demonstrated that BCVA in the better eye was the predictor of vision-related QoL in these groups of patients (P-value < 0.001). Female gender was significantly associated with lower QoL scores compared to males in the univariate linear regression model (P = 0.006). Sherwood et al.[4] showed that the female gender had low activities of daily vision scale (ADVS) scores and a poor quality of life. Min et al. found that the female gender was associated with lower QoL, and were more sensitive toward the symptoms of their disease, thus experiencing a greater negative impact on their QoL.[24] These could be the reasons for experiencing a poor QoL among the female gender in our study also. Monocularity, female gender, and older age were the probable factors in our study, which affected psychosocial health, confidence, outlooks, and thus the QoL in these patients.

In our study, we found mental health disturbance and dependency as the main factors affecting the QoL, followed by dark adaptation and glare and distant vision problems. Nelson et al.,[8] in their study, found dark adaptation and glare to be the factors responsible for the lowest visual performance among glaucoma patients. In addition to a generalized reduction in vision-related QoL, monocular patients report specific problems with seeing objects in their peripheral visual fields and feel that they accomplish less or are limited in the length of their participation in work or other activities.[22] Similar results were found in our study. Many of our participants stated that while walking they faced problems in noticing any animals/vehicles or perceiving the speed breakers and holes on the road. The majority of our patients had a feeling of being a burden on their family members.

The median composite score for group 1 was 54.62 and for group 2 was 45.38. The score was lower in the control group than those in glaucoma patients; however, the difference was not statistically significant between the groups (P = 0.367). Patients in both groups faced similar problems, more or less to the same extent. QoL in monocular patients with glaucoma and patients of other etiology is poor. More attention should be given to monocular patients for reducing their fear of blindness at diagnosis and over time because these patients are more worried about the loss of vision in their only remaining functional eye. Special attention should be paid to glaucoma patients because these patients are more worried due to the bilateral involvement of glaucoma and the fear of complete blindness. These patients should be counseled constantly to cope with mental and psychosocial health-related challenges. As per the results of our study, we concluded that it is important to provide accurate and appropriate information about glaucoma at every visit by expert healthcare professionals to prevent patients from developing undue anxiety and depression. Continued efforts to refine QoL assessment will further our understanding of the impact of glaucoma on the lives of millions of patients.[29] More work is needed to delineate the systemic, psychological, and ocular influences of QoL in glaucoma patients.[26,30,31]

QoL assessment is subjective; two patients with similar loss of visual ability from glaucoma may rate their QoL differently. Personality and other psychological factors may influence how questions are answered. Some will tend to minimize, whereas others may over-emphasize their functional impairment.[32] Limitations of our study are certain factors, such as marital status and employment status of patients, which were found to have an effect on QoL and were not included in the study.

To our knowledge, our study is the first study to assess QoL in monocular glaucoma patients in the Indian population, with the largest sample size reported among monocular studies so far. Also in our study, we compared the differences in VRQoL of monocular visual loss in patients with different etiologies.

Conclusion

Monocular patients have poor general and vision-related QoL. Depression associated with monocularity and the perception of dependency and being a burden on their family members greatly impacted the mental health of the participants. Patients must be educated about the disease and its association with lifelong treatment. Monocular patients must be given attention, especially those affected by glaucoma, for reducing their fear of blindness.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.