Glaucoma is an umbrella term for an eye condition that can potentially lead to a visual impairment, which is permanent. This article presents a discussion of the most common type of glaucoma to affect the older age group—chronic open angle glaucoma (COAG), also known as primary open angle glaucoma (POAG). The discussion takes a biopsychosocial approach to facilitate connections to holistic patient care.
Epidemiology
The ageing world population is rapidly increasing. In 2019, 9% of the population were over 65 years and the United Nations expect this figure to almost double to 16% by 2050. An acceleration of older adults implies that people live longer and therefore, will be susceptible to age-related health conditions. Ageing is a known risk factor for many eye conditions (WHO, 2022). Further projections, specifically regarding COAG in the UK, suggest that by 2025, 44% of the aging population will have the condition (Royal College of Ophthalmologists, 2021). Some eye conditions can cause impaired vision, which affects 2.2 billion people globally (WHO, 2022). COAG is one such condition and community nurses’ (CNs) caseloads are likely to have patients with this eye condition.
Older adults are susceptible to COAG; other r isk factors include: genetic predisposition (Wiggs, 2022); people over 40 years of age; and people of Asian and African heritage (Salmon, 2019). COAG is also linked to other factors such as the use of topical steroids (eye drops) (Allison et al, 2020), obstructive sleep apnoea (Cheong et al, 2023), high blood pressure, diabetes and smoking (Mahabadi et al, 2023).
Anatomy, physiology and pathology of chronic open angle glaucoma
An understanding of the bioscience of COAG enhances CNs’ understanding of the condition and informs the care and support they can provide for their patients. COAG is a progressive, bilateral eye disorder characterised by raised intraocular pressure, with the potential to result in irreversible visual impairment. Visual loss is slow and gradual and in the initial stages, goes unnoticed by the individual. Vision begins to deteriorate from the periphery and progresses to central visual loss (Salmon, 2019; Mahabadi et al, 2023).
COAG and the relationship with vision loss is due to an imbalance between the flow of the aqueous in the eye and its drainage out of it. The associated anatomy and physiology is widely acknowledged, as follows (Batterbury and Conor, 2019; Salmon, 2019). The aqueous is a transparent fluid, which is continually produced by ciliary processes in the ciliary body. It is situated at the front of the lens and in the anterior chamber of the eye. It contributes to maintaining the shape of the anterior chamber and provides nourishment to the posterior cornea, which is the transparent structure at the front of the eye. The majority of the aqueous fluid drains through a sieve-like structure known as the trabecular meshwork. The physiological production and drainage process maintains a balanced intraocular pressure (IOP). A normal range measures at 15–21mmHg IOP. It is noted that diurnal variations may occur and the IOP may be slightly higher in the morning (Machiele et al, 2023). An IOP approximates a range of 26–30 mmHg, and contributes to the loss of visual fields (Mahabadi et al, 2023). The physiological response to raised IOP limits the blood flow to the optic disc, damaging nerve fibres and causing cupping of the optic disc nerve head. The damage is irreversible.
There is currently no glaucoma screening programme in the UK, and the insidious and asymptomatic nature of COAG means that it is initially detected during a routine eye test at the opticians (Kastner and King, 2020). A range of eye and vision assessments are performed to inform decision-making regarding referral from the primary to secondary sector for further visual assessment, diagnosis confirmation, and if necessary, treatment (National Institute for Health and Care Excellence, (NICE), 2022). A diagnosis is not based on the IOP measurement as a single factor.
Access to glaucoma care
Vision damage due to COAG is irreversible but IOP is modifiable; therefore, it is imperative that patients have access to glaucoma care services. Patients with COAG account for 20% of ophthalmology outpatient activity (Royal College of Opthalmologists (RCOpth), 2020). The ageing population, combined with the effects of the pandemic on an already financially challenged healthcare sector, have led to an increase in referrals of people with suspected chronic glaucoma to the secondary sector (Fu et al, 2022). Many areas of healthcare have instigated virtual clinics to mitigate the waiting lists influenced by the pandemic. However, the virtual clinic is well-established in ophthalmology, especially in glaucoma care. Patient care in virtual clinics and subsequent outpatient visits is frequently managed by the non-medical ophthalmic multidisciplinary team, including glaucoma nurses and glaucoma technicians within the glaucoma patient care pathway (Bubb et al, 2021). Virtual glaucoma clinics reduce the pressure on ophthalmic service capacity and are well-received in patient satisfaction data (Nikita et al, 2023).
Patient care interventions
COAG interventions are guided by NICE (2022). These include Selective Laser Trabeculoplasty (SLT), trabeculectomy surgery and eye drop therapy.
Currently, SLT is suggested as the first line of treatment for patients who are newly diagnosed with COAG (NICE, 2022) SLT is a minimally invasive procedure, which increases the flow of aqueous through the trabecular meshwork (Mahabadi et al, 2023). Patients who do not respond to or are not suitable for SLT may be offered surgical procedures such as a trabeculectomy or may require long-term eye drop therapy, with prostaglandin eye drops to reduce intraocular pressure by increasing aqueous flow through the trabecular meshwork (NICE, 2022).
Eye drop therapy
Eye drop therapy encompasses the biopsychosocial approach to nursing care. Eye drops are prescribed medications and should be treated as such by healthcare professionals, patients and their families. As with systematic drugs, eye drops must be instilled at the right time, in the correct way and side effects known.
Eye drops are efficient at lowering IOP and preventing further deterioration of vision and visual field loss. Table 1 demonstrates the broad range of eye drops that are available for use. Eye drop efficacy is associated with how patients adhere to the prescribed eye drop regime and the effectiveness of their eye drop instillation technique. However, adherence is often challenging for a variety of reasons. For example, they have more than one type of eye drop to instil (Cvenkel and Kolko, 2022) or may have discomfort, such as dry eyes and irritation, caused by the preservatives in some eye drops (Fineide et al, 2022). Other widely acknowledged barriers to adherence include personal health beliefs, motivation, memory (Mcdonald et al, 2019) and dementia (Read et al, 2018). Adherence can be improved by eye drop aids, motivational interviewing (to elicit behavioural changes), smart phone reminder alarms, and patient-focused educational interventions (Buehne et al, 2022).
Table 1. Types of eye drops available for use
| Class of drop | Examples | How they work | When to take | Possible side effects |
|---|---|---|---|---|
| Alpha agonist | Apraclondine, brimonidine | Reduce production of fluid in the eye | Twice or thrice a day | Dry mouth, tiredness, weakness. Occasional allergic reactions—if your eye goes red, sore and sticky, seek medical advice |
| Beta blockers | Betaxolol, carteolol, levobunolol, timolol | Reduce production of fluid in the eye | Morning or twice a day | Slow pulse, dizziness, tiredness. Occasionally cause depression, loss of libido or impotence |
| Carbonic anhydrase inhibitors | Brinzolamide, dorzolamide | Reduce production of fluid in the eye | Twice or thrice a day, or twice a day if taken with another drop | Redness of the eye, crusty eyelashes, fatigue, bitter taste |
| Cholinergic inhibitors | Pilocarpine | Improve flow of fluid out of eye | Three or four times a day | Itchy eyes, poor vision in low light, sensitive eye, blurred vision |
| Prostaglandin analogues | Bimatoprost, latanoprost, tafluprost, travoprost | Improve flow of fluid out of the eye | Once a day, usually at night | Pink eye, iris may get darker, longer and darker eyelashes, darkening of skin around eye |
Note: Adapted from Glaucoma UK (2020)
Religious fasting such as Ramadan may affect a person’s adherence to their glaucoma drops. While this practice is not obligatory for people with health conditions, there is a belief that instilling eye drops will break the fast. As a result, some people may decide not to instil their drops (Kumar et al, 2007). Eye drops can travel from the eye to the throat and this influences such a perception. The charity Glaucoma UK offers reassurance from Islamic scholars that eye drops do not break the fast; a method known as punctal occlusion is an alternative. Punctal occlusion prevents eye drops passing into the throat—a practice which may be of benefit to people who are fasting, preventing the systemic drainage of the eye drops, thereby, maximising efficacy and reducing side effects.
Generally, evidence shows that eye drop adherence is multifactorial and signals the imperative for an individualised approach to supporting patients to instill their eye drops as prescribed.
Guide to instilling eye drops
A correct eye drop instillation technique is essential for the correct therapeutic dose. Patients/family/carers should be supported to instil their own drops safely and effectively. Assessment of a patient’s ability to instill eye drops is an essential aspect of nursing care. Continuous assessments will identify any cognitive or physical changes in the patient, which may impact on their eye drop technique over time. CNs can discuss and observe the technique with their patients to educate them about the importance of adhering to eye drop therapy and provide advice on adaptations, and position of the hands, for example, depending on manual dexterity.
Glaucoma UK has published its ‘Step by Step’ guide to instilling eye drops (Table 2). The guide also advises on punctal occlusion, where a finger is gently placed over the tear duct to prevent the eye drop from travelling down the throat, therefore maximising the potential for therapeutic absorption of the eye drop. Drop calendars, such as the one from Glaucoma UK are effective reminders for eye drop installation.
Table 2. Step-by-step guide to instilling eye drops
| No. | Steps | Method |
|---|---|---|
| 1 | First, wash your hands. Then, if it says so on the bottle, shake it | Get into a comfortable position. You may find it easiest to sit in front of a mirror, or you could lie down |
| 2 | Standing in front of a mirror | Pull down your lower lid with a finger of one hand, to create a ‘pocket’. With the other hand, squeeze or tap the bottle so one drop goes into the pocket |
| or | ||
| 2 | Wrist on knuckle (WOK) | The WOK technique is particularly helpful in holding the bottle steady or if you have long nails:
|
| 3 | Lying down | If you are lying down, you may find it easier to balance the bottle on the bridge of your nose. Look upwards and squeeze the bottle. The drop should fall into your eye. If it does not, it will be in the corner by your nose. Turn your head slightly to the side and the drop should run into your eye |
| 4 | Keeping the drop in your eye |
|
Try to put the drop in at the same time each day. If your drop needs to be put in twice a day, try to leave 12 hour gaps between drops.
Note: Adapted from Glaucoma UK (2022)
Psychosocial support
A diagnosis of chronic glaucoma and potential vision loss can be devastating for patients, their family and carers. Glaucoma requires lifelong treatment (RCOpth, 2021); therefore, psychosocial support, not only at diagnosis but at all stages of the disease progression, is vital for the well-being of the patient. A person’s quality of life, defined by WHO (2012) as an individual’s perception of their position in life, should be recognised as part of holistic nursing care. In particular, loss of confidence resulting from visual impairment, and falls risks due to related adjustment to bright light and glare (Enoch, 2019) severely limit a person’s engagement in social activities (Nayyar et al, 2022). People with a visual impairment may also experience Charles Bonnet Syndrome (CBS). The WHO (2023) defines CBS as visual hallucinations experienced by some people with a visual impairment. CBS is experienced by 1 in 5 people with a visual impairment (Subhi et al, 2021); however, the condition is often not known to the individual or healthcare professionals and consequently, a person can become further isolated and distressed by hallucinations that they may incorrectly relate to mental health or cognitive decline.
Glaucoma nurses provide a point of contact for patients in terms of interventions such as virtual clinics, eye drop teaching and eye health (Bubb et al, 2021). The glaucoma nurse is part of the ophthalmic healthcare professional team (NICE, 2022), supporting patients with shared decision-making. This facilitates a therapeutic approach and holistic care.
The eye liaison clinic officer
The eye liaison clinic officer (ECLO) has a pivotal role in providing information and support. ECLOs are supported by the Royal Institute of Blind People (RNIB) charity and are based in outpatient clinics. Benefits, housing, low vision and emotional support are among the categories credited to the ECLO (Llewellyn et al, 2019; Menon et al, 2020). Should the patient be at a stage that a Certificate of Visual Impairment is needed, then the ECLO guides them through this difficult administrative and emotional process. However, due to funding, the ECLO service is not available throughout the UK, depriving glaucoma patients (and others) with essential support at difficult times in their lives (Llewellyn et al, 2019).
Driving
Driving affords an individual with independence and maintenance of social contacts. However, the progression of COAG impacts on driving safely and legally. Individual patient vision data informs the healthcare professionals on advising patients if they should report to the Driver and Vehicle Licensing Agency if they do not meet the required standards for driving (Royal College of Nursing, 2022).
Patients’ visual loss is often perceived by others as being obscured by ‘black patches’; yet, many patients with visual loss indicate that they have no visual symptoms (Crabb, 2016). Asymptomatic and insidious loss of vision can be critical to people with COAG, who may not be aware of the potential risks of activities such as driving. Difficult conversations with patients about vision and driving are an inevitable component of patient care. However, such conversations may not happen as the busyness of the ophthalmic clinic environment counteracts opportunities for such important healthcare/patient conversations (Mercieca et al, 2023).
Falls
COAG-related visual impairment affects depth perception balance and can put the patient at risk of falls. Additional risks are associated with living in a socially deprived area and if a person is socially isolated (Mehta et al, 2022). Furthermore, COAG-associated falls are estimated to cost the NHS £1.2 million over a 6-year period (McGinley et al, 2019), highlighting not only the resource associated issues but also the consequences on a person’s overall physical and social well-being. Falls risk assessment is therefore imperative to the holistic nursing care of a person with COAG.
Conclusion
COAG has physical, psychological and social impacts on a person’s life. The role of the community nurse is to recognise COAG not only as a condition that requires nursing and ophthalmological intervention but as one that has a far reaching impact. Adequate knowledge and understanding of COAG by the nursing and healthcare team can have a positive effect on a person’s well-being. The fast pace of patient care should not detract from the holistic nursing care that people with COAG and their families and carers need to support their well-being, quality of life and positive engagement in their social world.