Glaucoma may cause vision loss and irreversible blindness if not treated. However, vision loss because of glaucoma can be prevented if detected early and properly treated. However, early identification of glaucoma and the effectiveness of screening programmes depend on the compliance with follow-up care.¹ There are many reasons why glaucoma remains difficult to arrest within populations. One of the reasons is that it is asymptomatic, and thus, many people do not seek immediate medical care.² For example, the United State of America’s (USA) Preventive Service Task Force reports that evidence to support glaucoma or visual acuity screening is inadequate. More than half of the patients with abnormal screening results fail to come back for confirmatory follow-up eye examination as expected. Furthermore, glaucoma affects the quality of life through its treatment, and vision loss requires a demanding life-long multidrug regimen.^3,4

Loss to follow-up (LTFU) refers to patients who at one point in time were actively participating in a clinical research trial but have become lost (either by error in a computer tracking system or by being unreachable) at the point of follow-up in the trial. However, patients can become lost to follow-up for many other reasons.^5,6 Participants were considered lost to follow-up if they had not reported at the referral examination (up to three different scheduled times) and failed to answer contact calls or to reschedule a missed or cancelled an appointment in up to three attempts on different days. Several studies^5,7,8 have indicated that 80% of glaucoma patients do not adhere to treatment recommendations hence LTFU. Poor adherence to medication is a multifactorial issue with many contributing factors such as patient-centred factors, therapy-related factors, social and economic factors.^5,9

Patient-related factors can negatively affect adherence to glaucoma treatment. Non-adhering patients are at greater risk of poor outcomes than adherent patients. Poor adherence can result in the ineffectiveness of treatment, whereas improvement of adherence could prevent the need to use multiple glaucoma treatment.^10,11 Non-adherence to glaucoma treatment is a global problem. Several studies have been conducted worldwide regarding LTFU amongst glaucoma patients. Lifelong monitoring is an integral part of glaucoma management and lack of adequate follow-up can pose serious consequences for glaucoma patients on medical or surgical therapy. A study conducted in sub-Saharan Africa by Kyari et al.¹² indicated that some patients fail to return for follow-up if they assumed that their treatment was no longer effective and when patients felt better and concluded that they had no need of further treatment. Long distances from hospitals and economic implications of repeated consultations and negative attitudes of healthcare workers were cited as factors contributing to LTFU.

Although glaucoma is incurable, it is treatable. The primary objective of glaucoma therapy is to prevent the progressive vision loss, disability and blindness. Regular monitoring is vital in the lowering of intraocular pressure (IOP) and maintaining vision. It is recommended that glaucoma patients are seen by the ophthalmologist at least every 6–12 months for a comprehensive eye examination according to the American Academy of Ophthalmology.⁷ Similarly, the South African Glaucoma Guidelines, which are in line with International Glaucoma Society Guidelines, recommend that patients with controlled glaucoma should be seen three times per year, whereas those with uncontrolled and complicated glaucoma should be seen up to six times a year.¹³ Therefore, the purpose of this study was to increase the understanding of reasons for LTFU amongst glaucoma patients in the selected rural hospitals of the Limpopo Province, South Africa.

There were more female (69%) than male (31%) respondents for this study. This disproportionate sex distribution of respondents might have been influenced by the fact that more female respondents access healthcare facilities than male respondents. Similar findings were reported by different authors who indicated high numbers of female respondents than male respondents in their studies.^19,20,21 Regarding the demographic data, ages of the respondents were found significant in relation to knowledge and awareness that glaucoma requires lifelong treatment. This is similar to the findings of Aghedo et al.²⁰ in KwaZulu-Natal, South Africa. In an urban population of South India Durowade et al.²¹ revealed that there is a strong relationship between the age of the respondents and glaucoma knowledge. Respondents older than 30 years were significantly more likely to be aware of glaucoma than those below 30 years. In Australia, Curtis et al.²² reported that patients who are 65 years and older had adequate knowledge than younger patients in understanding eye drop instillation. The study further reported that older patients (above 65 years) were often happy to ‘do as they are told’ because of the trust they had in healthcare provider. However, this study contrasts with many other study findings by Ogbonnaya et al.²³ and Mbadugha et al.²⁴ in Lagos, Nigeria, and Prabhu et al.²⁵ in South India who reported that age and religion had no influence on glaucoma awareness.

Also in contrast with the present study’s findings, a study in Eastern Nepal found that there was no association amongst age, awareness and knowledge.²⁶ Some studies further indicated that even though many of the respondents had heard about glaucoma, only a few of them had accurate understanding of glaucoma disease.^26,27 However, in the present study, we observed a reduction in the higher level of knowledge of patients with increasing age. A possible explanation for this finding may be the fact that older patients forget information more easily than younger patients because of senility. Most respondents (249), that is, about 58% in this study, reported that glaucoma disease has no symptoms. Similar results were reported by Abdull et al.²⁸ and Altangerel et al.²⁹ In India, Bart et al.³⁰ stated that glaucoma is asymptomatic and painless and causes irreversible damage to the optic nerve. Similarly, Ichhpujani et al.³¹ indicated that damage caused by glaucoma disease to the optic nerve is reversible.

In this study, respondents exposed relatively little or a lack of knowledge about the glaucoma disease. Ichhpujani et al.³¹ and Altangerel et al.²⁹ reported similar results that knowledge about glaucoma disease was inadequate amongst patients in North India and Canada respectively, as most participants claimed to be aware of glaucoma but did not understand the symptoms, risk factors and treatment. These authors further reported a startling fact of medical personnel (35% of nurses and 20% of doctors) who did not understand that glaucoma is associated with high blood pressure in the eye and that it had an effect on the optic nerve.³¹ However, in Northern Nigeria, Abdull et al.³² stated that there was adequate knowledge amongst patients although patients failed to understand that the purpose of glaucoma treatment is to preserve the existing vision rather than restoring sight.

Respondents in this study revealed that they sometimes forget to administer their eye drops. Different authors Kontoh¹¹ and Ajayi³³ and Blondeau et al.³⁴ similarly found that forgetfulness to medications contributes to non-adherence. Olthoff et al.³⁵ and Tsai³⁶ stated that glaucoma patients forgot their medications because there is no direct advantage from the eye drops and no immediate disability from the disease. Also, patients who failed to accept their glaucoma disease and the use of treatment for life tend to forget easily as attested by Tsai.³⁶ The findings concur with the study results by Newman-casey et al.⁵ who reported that 62% of the patients cited forgetfulness as their number one barrier with both non-adherent and adherent patients.

This study revealed that some respondents had a negative attitude towards glaucoma treatment and management. Most respondents (73%) felt very bad when they were diagnosed with glaucoma and did not want other people to know about their disease. This is attributed to the fact that respondents are afraid of going blind and are worried about living with a chronic condition. Some respondents felt uncertain about their future because of glaucoma disease. Similar results were reported in a South African study conducted in KwaZulu-Natal with 95% patients showing a negative attitude towards their glaucoma diagnosis but on the other hand feeling happy with the use of their eye drops.²⁰ In this study, more than half of the study respondents were not aware that they should do regular glaucoma follow-up. This is attributed to the ineffective information given to some of the patients. Similar results were attested by Demirtaş et al.³⁷ who mentioned that glaucoma patients were not aware about the importance of regular eye examination. However, the study by Thompson et al.¹⁷ reported that other patients believed in the importance of follow-up even when there is no visible change in their vision after using the medications.

This study also revealed that some respondents’ poor practice contributed to non-compliance with the treatment and management of their condition leading to LTFU. The study showed that 219 (51%) of the respondents were not compliant with treatment and management. Patients on single eye drop adhered more to their glaucoma medication than those on multiple eye drops. Stryker et al.³⁸ and Castel et al.³⁹ stated that adherent patients believed that medications prevent disease progression and maintain vision. The study further mentioned about the benefits of using eye drops regularly. However, some of the study respondents indicated that they sometimes use traditional eye medications to treat glaucoma disease and others consult their spiritual healers. Some of the respondents perceived that glaucoma is caused by witchcraft or evil spirit. De-gaulle et al.⁴⁰ reported similar findings in their study stating that glaucoma patients preferred alternative eye care service such as traditional healers and also preferred local pharmaceutical shops than visiting an ophthalmologist or optometrist. Similar studies conducted by Abdull et al.²⁸ reported that traditional healers were the most respected and trusted people in some of the African countries. The study further indicated that environmental factors greatly contributed to respondents’ missing clinic visits resulting in non-compliance. Factors such as financial means, no escort to accompany respondents and long queues at the clinics were raised.

The study showed consistency with those conducted by Sun et al.⁴¹ in China and Radhakrishnan et al.⁴² in India who reported that patients had failed to attend their follow-up and travelling difficulty were noted as reasons for non-attendance. Ehiemua⁴³ also obtained similar findings in Namibia. Several researchers found that patients spend many hours waiting to access care at every point because of reasons such as hospital staffs’ inability to retrieve patients’ files, patients queuing for a long time, difficulty in scheduling the appointment making use of an interpreter during consultation and patients from different clinics made to attend at a single point.^44,45,46 Similar studies conducted by Momoh et al.⁴⁶ in Southern Nigeria and Abdull⁴⁴ in South-East Nigeria discovered that patients residing more than 50 km from the health facility showed poor follow-up than respondents living nearer to health facilities. In California (United States [US]) and Philadelphia (US), researchers reported that glaucoma patients expressed financial barriers and lack of escort to access healthcare services as attributing to LTFU. Thompson et al.¹⁷, Kim et al.⁴⁷, Lee et al.⁴⁸ and Landers et al.⁴⁹ pointed out that rural healthcare is characterised by challenges such as longer commuting distances, which lead to slower access to critical care during emergencies. One study shows that travel and financial cost are intrinsically linked and it is so difficult to separate them as distinct components.³⁸

The study was only conducted in selected hospitals of Vhembe district. Therefore, the results cannot be generalised to the rest of Limpopo Province. Moreover, the study was restricted to patients with established glaucoma presenting themselves at hospitals that only provide glaucoma services. Further research work should be done on glaucoma patients using qualitative methods to try and get detailed information regarding LTFU.

Our study shows that non-adherence to scheduled follow-up appointment amongst glaucoma patients in rural hospitals is prevalent. Patients outlined various reasons that contributed to their glaucoma LTFU. The reasons included inadequate knowledge regarding the disease itself, perception that compliance with medications and follow-up are less important, forgetfulness, financial difficulties, lack of an escort to the clinic, travel distance from home to the clinic exceeding more than 15 km, long hospital queues and also the belief that glaucoma is caused by witchcraft or evil spirit. Similarly, the study concurs with other studies that were conducted mostly in sub-Saharan Africa. Therefore, appropriate measures need to be taken to strengthen eye care follow-up amongst glaucoma patients.

Patients should be informed about the advantages and disadvantages of glaucoma LTFU. Family members and community should be educated on eye conditions such as glaucoma so that they should be involved in the care and offer support. Vhembe District Department of Health should provide one or more mobile clinic vans for easy access to most glaucoma patients who stay far from the health facilities. Eye healthcare practitioners should be provided with training on motivational interviewing to equip them with skills to motivate glaucoma patients to remain in care. Campaigns to enhance public eye awareness on glaucoma diseases should be launched to improve the effectiveness of health promotion and prevent unnecessary blindness. All this could significantly improve the quality of life for these people and their families, whilst at the same time reducing national expenditure by healthcare services and increasing productivity in the economy of the country.