Introduction

Glaucoma encompasses a spectrum of diseases characterized by degeneration of the retinal ganglion cells leading to optic disc damage and irreversible vision loss [1]. Being the second most common cause of blindness worldwide, glaucoma affected 64.3 million adults in 2013 and is expected to affect 111.8 million by 2040 [2,3]. Due to its asymptomatic nature, lack of awareness, and low levels of referral, the prevalence of glaucoma is under-reported [4]. Additionally, the chronicity of the disease implies that patients with glaucoma may be subjected to various quality of life and therapeutic concerns due to long-term noncompliance, gender discrimination, and health literacy, all of which are influenced by the patient’s awareness towards their disease [4,5].

Despite the discrepancies between developed and developing nations in terms of knowledge of patients with glaucoma [6,7], the overall level of knowledge is poor [8,9]. Throughout the literature, factors such as socioeconomic status, short disease duration, and advanced age were negative predictors of glaucoma knowledge [8,10–12]. Poor glaucoma knowledge influences the clinical progression of the disease as it contributes to a lack of adherence to palliative drug regimes, and the underestimation of regular ophthalmic examinations [2,5,13]. Subsequently, those poor clinical presentations are associated with worse treatment outcomes as cases might be treated with more complex surgical options to halt the rapidly progressive and irreversible retinal damage [5,14]. Therefore, knowledge of glaucoma could be of vital importance as a target of interventions aiming to improve the lifestyles among those with glaucoma, particularly high-risk groups (e.g., geriatrics). Gatwood et al., (2022) demonstrate that disease-related educational interventions improve adherence to glaucoma treatment [15].

The literature evaluating glaucoma knowledge within the Middle East and therefore its treatment implications, is scarce. In fact, an accurate estimation of knowledge is tricky to calculate due to the juxtaposition with the concept of awareness. It should be noted that awareness refers to the generalized or diffuse knowledge of a particular concept (e.g., have you heard of glaucoma?), while knowledge refers to any information that is factual in nature (e.g., prevalence, etiology, risk factors, etc.) [16].

Among Jordanians, glaucoma is the third leading cause of severe bilateral blindness [17]. Glaucoma awareness throughout the population was estimated to be approximately 38.8% [18]. However, there exist no reports evaluating glaucoma knowledge among Jordanians. Thus, this study aims to assess the glaucoma knowledge and adherence to care seeking behaviors among Jordanian patients with glaucoma to formulate relevant educational policies and compliance assuring strategies.

Materials and methods

We conducted this cross-sectional study using a self-administered questionnaire on patients visiting the ophthalmology clinics at Jordan University Hospital from October 2021 to February 2022. The Jordan University Hospital is the largest tertiary and academic health provider in Jordan. In addition, it is the largest referral center for all of central Jordan serving over four million patients.

Patients were enrolled into two groups: The first group consisted of participants with a clinically proven diagnosis of primary open angle glaucoma of at least 6 months and are on medications. Diagnosis of glaucoma was established using slit lamp examination, visual field testing, gonioscopy, and imaging (i.e., Optical Coherence Tomography). Patients with secondary glaucoma (e.g., pseudoexfoliation syndrome, pigment dispersion syndrome, neovascular glaucoma, inflammatory glaucoma, and medication-induced glaucoma) were excluded. The second group of participants consisted of those who were diagnosed with any vision limiting ophthalmic conditions with the exception of long-standing glaucoma. Such conditions include cataracts, diabetic retinopathy, macular degeneration, optic neuritis/atrophy, cerebrovascular disease, and hereditary retinal disorders. Participants that were younger than 18 years of age, suffered from mental/psychiatric illnesses, and were unable to consent to participation in the survey were excluded from the study. Moreover, participants that failed to complete at least 80% of the questionnaire were also excluded. Systemic random sampling was adopted to recruit every 4^th patient from the ophthalmology clinics.

Results

A total of 256 participants filled out the survey, of which 53.1% were diagnosed with glaucoma while 46.9% had ophthalmic conditions other than glaucoma. Our sample of participants was characterized by a mean age of 52.2 ± 17.8 years and a male to female ratio of 1.04:1. The majority of the sample resided in the capital city of Amman (66.8%), had a bachelor’s degree or higher (50.8%), and earned less than 500 JDs in monthly income (64.5%). Characteristics of participants with glaucoma were similar to those without glaucoma with the exception of age (p = 0.009), clinic visits per month (p <0.001), clinic visits per year (p <0.001), and family history of glaucoma (p = 0.006). Table 1 describes the sociodemographic characteristics of the recruited cohort.

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Table 1. Sociodemographic characteristics of the studied population.

https://doi.org/10.1371/journal.pone.0285405.t001

Amongst participants with glaucoma, the mean time since glaucoma diagnosis was 9.7 ± 9.4 years, and the mean time since the start of glaucoma treating drops was 9.1 ± 8.7 years. Participants with glaucoma used a mean of 2.4 ± 1.4 medications and a mean of 3.3 ± 2.9 drops per day for the treatment and/or control of their glaucoma. Furthermore, participants were subjected to a mean of 1.6 ± 2.7 surgeries for the treatment of glaucoma in their lifetime.

Table 2 demonstrates the responses of participants towards glaucoma knowledge items. Overall, participants with glaucoma were more aware of their disease than participants with other ophthalmic conditions. Participants with glaucoma were significantly more likely than their non-glaucoma counterparts to recognize that glaucoma is a predominantly ophthalmic disease (X²(2) = 11.16, p = 0.004), is the result of increased intraocular pressure (X²(2) = 19.56, p <0.001), can progress to optic nerve damage (X²(2) = 29.41, p <0.001), and is more likely to increase in incidence with age (X²(2) = 9.13, p = 0.010). Moreover, they were more likely to think that stress (X²(2) = 6.05, p = 0.048), prolonged computer usage (X²(2) = 10.05, p = 0.007), prolonged smartphone usage (X²(2) = 11.59, p = 0.003), and prolonged reading (X²(2) = 9.15, p = 0.010) may worsen symptoms of glaucoma. Compared to ophthalmic non-glaucoma participants, those diagnosed with glaucoma were familiar with the nature of their treatment as they are vigilant of the ability of medications to control glaucoma (X²(2) = 19.98, p <0.001), and that glaucoma treatment is lifelong (X²(2) = 32.97, p <0.001).

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Table 2. Responses of participants to knowledge items.

https://doi.org/10.1371/journal.pone.0285405.t002

Nonetheless, both groups of participants portrayed variability in their awareness towards types of glaucoma, certain risk factors associated with glaucoma (i.e., myopia), effect of certain medications on glaucoma development (e.g., corticosteroid containing drops), and the post-operative implications of the surgical management of glaucoma.

Most participants were aware of glaucoma symptoms with the exception of convulsive seizures (9.0%). Moreover, only 27.3% were aware that glaucoma can manifest as an asymptomatic entity. Participants with glaucoma were significantly more likely to report vision loss (p = 0.008), and pain, redness, nausea, and vomiting (X²(1) = 12.11, p = 0.001) as symptoms of glaucoma than their ophthalmic non-glaucoma counterparts. Similarly, the treatment of glaucoma with medications is significantly more recognized by participants with glaucoma (X²(1) = 8.11, p = 0.006). The least reported modality of treatment among both groups was surgery (57.5%, and 69.1%).

The least commonly recognized complications of glaucoma treatment were dyspnea (10.9%), bradycardia (12.1%), and elongation of eyelashes (18.0%). In terms of sources of information, participants with glaucoma were significantly more dependent on ophthalmologists for disease-specific information (X²(1) = 80.62, p < 0.001). On the other hand, ophthalmic non-glaucoma participants were significantly more likely to rely on close social circles (X²(2) = 15.28, p < 0.001). Table 3 describes knowledge about glaucoma presentation and its treatment.

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Table 3. Awareness of risk factors, treatment options, and difficulties associated with glaucoma.

https://doi.org/10.1371/journal.pone.0285405.t003

Compared to their ophthalmic non-glaucoma counterparts, those diagnosed with glaucoma faced significantly more daily life difficulties due to their ophthalmic disease (p <0.001). Such difficulties included identifying persons (p = 0.005), reading (p = 0.001), using the stairs (p = 0.009), driving (p = 0.031), walking alone (p = 0.015), among others. Overall, most participants believed that more information on the pathophysiology/progression (83.6%), treatment (68.4%) of glaucoma, and other practical advice on how to manage disease fluctuations (71.1%) are needed to improve awareness and knowledge of glaucoma.

Univariate analysis shows that participants with glaucoma have significantly higher knowledge scores (t(254) = 4.31, p <0.001) and were able to recognize more glaucoma symptoms than their non-glaucoma counterparts (t(254) = 3.18, p = 0.002). Similarly, those with a positive family history of glaucoma displayed higher knowledge (t(249) = 2.81, p = 0.005) and a relatively higher ability to recognize glaucoma symptoms (t(249) = 2.07, p = 0.039). Knowledge scores did not differ between genders, area of residence, educational status, income level, or medical history (refer to Table 4). Moreover, the ability to recognize more symptoms and more treatment-related complications was positively correlated with higher knowledge scores (r = 0.302, p <0.001; r = 0.285, p <0.001, respectively). However, age (p = 0.130), number of clinic visits per month (p = 0.410), and number of clinic visits per year (p = 0.412) were not significantly correlated with knowledge scores.

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Table 4. Factors affecting glaucoma knowledge scores.

https://doi.org/10.1371/journal.pone.0285405.t004

Multivariate linear regression demonstrates that a family history of glaucoma (B: 1.539; 95%CI: 0.078–3.000; p-value: 0.039), higher symptom recognition score (B: 0.624; 95%CI: 0.083–1.164, p-value: 0.024), relying on ophthalmologists (B: 2.584; 95%CI: 0.983–4.185; p-value: 0.002), and the internet (B: 2.364; 95%CI: 0.845–3.883: p-value: 0.002) for glaucoma-related information are positive predictors of higher knowledge scores. Table 5 delineates the linear regression model for knowledge scores.

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Table 5. Predictors of knowledge score for the studied sample (n = 256).

https://doi.org/10.1371/journal.pone.0285405.t005

Discussion

Our study demonstrated that glaucoma knowledge among Jordanian ophthalmic patients is defective and extremely variable. Knowledge deficiencies are most pronounced in areas such as risk factors, neurological symptoms, adverse effects of over-the-counter medications of glaucoma, and post-operative management and expectations. Additionally, it appears that the extent of knowledge of recruited participants is only influenced by their glaucoma diagnosis and family history of glaucoma. Conversely, all other sociodemographic factors did not significantly impact overall knowledge.

The level of knowledge of glaucoma portrays significant variability across different reports throughout the globe. Jordanian reports show that only 34.1% of Jordanian patients were able to accurately define glaucoma despite their acceptable levels of awareness [26]. In terms of regional literature, a Saudi Arabian report demonstrates that patients with glaucoma exhibit poor knowledge, attitudes, and practices toward their disease [27]; a finding that was similarly observed among Iraqi ophthalmic patients [28]. An Iranian population-based survey demonstrated that only 46.6% demonstrated glaucoma awareness while only 19.2% were able to correctly define the disease [29]. Asian countries, the likes of Nepal and India, demonstrated low rates of glaucoma knowledge among hospital presenting patients ranging from 1.9% to 27% [30–32]. China, on the other hand, demonstrated that 51.6% of glaucoma patients visiting a tertiary university hospital were aware of their disease [33].

Great variance is noted among patients with glaucoma from African nation with rates ranging from 74% for Ghana, 36.8% for Nigeria, to 46.7% for Ethiopia [34–37]. On the other hand, Western nations such as Austria, Germany, the United States, Australia, and the United Kingdom display far superior rates of glaucoma knowledge ranging from 51% to 93% among both the public and patients visiting eye clinics [19,38–40].

While such variance among different studies could be attributed to differences between studied populations in terms of sociodemographic or clinical characteristics, inherent methodological differences make direct comparisons between reports extremely challenging. There seems to be an overlap, or rather a failure of distinction, between knowledge and awareness [22]. Across the aforementioned studies, measures of knowledge assessment were dramatically different in terms of content, format (e.g., number and type of questions), and definitions of proper knowledge, most of which were made based on arbitrary and/or convenient basis [41]. Furthermore, questionnaire-based measures were not always developed rigorously. Such discrepancies in development (e.g., presence or absence of pilot testing or expert group consultation) could have led to the observed heterogeneity of glaucoma-related knowledge.

We demonstrated that glaucoma patients are relatively more knowledgeable about glaucoma in comparison to ophthalmic non-glaucoma counterparts, yet the knowledge among the two groups was relatively poor. Such observation is fairly established within the literature and is expected as those with established glaucoma diagnosis may have received a greater amount of disease-specific knowledge from their doctors or close social circles at far higher frequencies of contact [23]. Literature shows that durations of glaucoma and follow-up are significantly associated with improved levels of knowledge [12,42]. Another plausible explanation is the reliance of ophthalmic non-glaucoma patients on friends and family for glaucoma-related information may predispose them to inaccurate or outdated information; a finding documented within a German survey [40]. Such reliance may indicate a gap of trust between patients and healthcare providers. On the other hand, the poor level of knowledge among patients with glaucoma could be attributed to the congestion of the Jordanian primary healthcare system which renders doctor-patient encounters less effective [26]. Increasing the number of physicians and fortifying their communication skills may ensure the appropriate delivery of vital glaucoma-related information to patients; however, this solution might be over-ambitious in resource-scarce institutions and developing nations.

Amongst the literature, several factors were implicated to have influenced glaucoma-related knowledge such as age, education, occupation, income, accessibility of ophthalmic care, duration of glaucoma, compliance to medications, family history of glaucoma, and type of glaucoma [20,22,33]. Chen et al., (2022) demonstrated a comprehensive review of such factors and showed that lack of conformity between the impact of different factors on glaucoma knowledge can be explained by differences in study design, characteristics of study populations, and methods of analysis [33]. In agreement with our investigation, several studies reported that participants with a family history of glaucoma were significantly more knowledgeable about their condition [12,26,40]. Such might be the case because having a family member with glaucoma may provoke the individual to search for more information and/or gather information during their appointment with the eye care professional [30]. Contrary to the literary consensus [21,25,33], educational level was not significantly associated with glaucoma knowledge among both groups of studied participants. This can be attributed to weakness in the Jordanian health-related educational programs for secondary and higher levels of education [26]. Additionally, while age did not significantly predict knowledge scores among included participants, it was a negative predictor of glaucoma knowledge within the literature. The latter could be attributed the low levels of health literacy in older individuals, neurological disease progression, or the inherent technological bias exhibited by younger participants [33,43].

Improving awareness was shown to help in early glaucoma detection, thus better control and recognition of its complications [25], which in turn will assist in mitigating healthcare costs and the overall clinical burden of disease [24]. We propose a number of evidence-based recommendations that may improve patients’ awareness to glaucoma. First, the implementation of a patient-held record (e.g., ‘Glaucoma Logbook) which encompasses everything related to glaucoma from its most common facts to the most relevant management details [44]. Second, the creation of a glaucoma-centric social club which was shown to predispose patients to higher levels of glaucoma knowledge, improved disease cognition, and improved compliance [45]. This can be administered through social media as services such as ‘WeChat’ was effective in improving patients’ education towards glaucoma and enhancing their willingness to utilize electronic services for their follow-up [23]. Third, the implementation of a telemedicine program which can both follow-up on patients with glaucoma and educate them at an extremely low direct and indirect cost [46]. Finally, the formulation of a patient-centered educational program was proven effective in enhancing the knowledge of patients with congenital and secondary glaucoma [47]. Such a program may take different forms ranging from seminars, written publications (e.g., brochures and leaflets), and video materials, to theory-based practical sessions given throughout a patient’s clinical visit. Among our participants, less than 50% of the proposed adverse effects of glaucoma medications were identified. Considering the wide spectrum of systemic side effects associated with beta-blockers and alpha-agonists, the aforementioned targeted solutions should focus on such deficiency [12].

The burden of ameliorating glaucoma awareness and knowledge should also be shared with governing bodies and health policymakers. Our multivariate analysis demonstrated that ophthalmologists and the internet are associated with increased levels of knowledge; an observation that was documented in China [33]. Concerned governmental authorities and health policymakers should increase the public’s awareness and knowledge by allocating more resources towards enhancing ophthalmology practice and utilizing internet-based solutions to reach a wide audience.

This study is not devoid of limitations. The small sample size might have impacted the statistical robustness by which knowledge scores are differentiated. Moreover, the study examines glaucoma knowledge in a different, yet more comprehensive, manner than the available literature thus it might underestimate its rates of glaucoma awareness. Moreover, data may be subjected to recall bias due to the self-reporting nature of the questionnaire. Finally, due to the lack of a standardized scoring system for glaucoma-related knowledge and awareness, direct comparisons with other studies proved difficult. Nonetheless, the strength of the study lies in its usage of a rigorously designed and validated questionnaire to evaluate glaucoma-related knowledge. Also, the study’s sample of glaucoma patients closely resembles the overall number of glaucoma patients treated at the JUH ophthalmology clinics thus high internal validity could be expected.

Conclusion

In light of this investigation, we have demonstrated that ophthalmic patients display average levels of glaucoma knowledge. Raising awareness through various programs and interventions may improve the lifestyles of patients with glaucoma, which may result in long-term mitigation of the economic burden associated with the disease and its complications. Concerned authorities should project their interventions through ophthalmologists and internet-based platforms due to their profound effect in shaping glaucoma-related knowledge.

Supporting information