Improving Adherence to Topical Medication in Patients with Glaucoma

Glaucoma is one of the leading causes of irreversible blindness globally, with nearly 80 million people estimated to be affected in 2020. Out of these 80 million, at least 10 % of those were classified as legally blind.^{1, 2}

The most common type of glaucoma is primary open angle glaucoma (POAG, where no identifiable cause for glaucoma is found), accounting for two thirds of all glaucoma cases. The second most common type is primary angle closure glaucoma, which is relatively more common in person of East Asian descent.^{6, 7} There are also numerous secondary causes of glaucoma. Most forms of glaucoma are associated with an elevated intraocular pressure (IOP) as the major risk factor and so current treatments are designed to work by reducing eye pressure. According to researchers, reducing IOP is the only treatment method that can stop or slow down the rate of vision loss due to glaucoma. Reducing eye pressure even in patients with normal pressure glaucoma (without high eye pressures) has been shown to slow progression.^3-14

Once a diagnosis of glaucoma is made, a management plan that includes lifelong monitoring of the optic nerve (the site of glaucoma damage), vision, visual fields, eye pressures, and health is required to prevent vision loss.¹⁵ 

A variety of options are available to treat glaucoma which include prescription pressure lowering eye drops, laser procedures or surgery. Generally, topical eye drops are the first choice of initial glaucoma treatment.^15,16

Topical medications are suitable for patients who are able to properly instil the eye drops themselves or who have someone to help them such as a family member or carer. As with any medications, topical pressure lowering drops may cause may have side effects, depending on the medication, in the eyes or systemically. These are discussed in detail by the eye care practitioner prior to commencement of treatment, together with strategies to minimise certain side effects. Your eye care provider will discuss these various risks and potential interactions with other health conditions and medications.

Using topical therapy is usually a life-long commitment for patients with glaucoma. Not adhering to therapy could result in irreversible vision loss. Understanding the disease process and how treatment helps are key factors for motivating patients to being organised and disciplined with the recommended treatment regime. Compliance is key to manage the successful treatment of glaucoma.^17,18 The majority of patients with glaucoma can achieve good control of their eye pressures if the topical medication is administered correctly, regularly, and persistently. Low adherence to glaucoma treatments can lead to elevated or fluctuating eye pressures and consequently worsening of vision.^17,19,20  

A range of strategies to improve treatment adherence are outlined below.

Reminders

A few studies have investigated the effect of setting regular reminders to improve adherence to taking glaucoma medications. At least in the short term, strategies like timely, automatic reminders can assist in treatment adherence, compared to if patients did not have any assistance.^23,24  

Smart drop bottles

Technological developments have allowed for the design of a smart drop bottle device with smart phone connectivity. This bottle works by detecting when the bottle is squeezed via a sensor and then records when drops are administered to a mobile phone application via Bluetooth.²⁵ The application also allows reminders to be set, and also serves as a monitoring mechanism.

Instillation aids

Eye drops require a specific technique for successful administration.²⁶ Some patients with physical difficulties such as handgrip strength, dexterity issues, arthritis, tremor can find instilling eye drops challenging. To assist with successful eye drop administration several new instillation aids have been developed such as the Easidrop and Xal-Ease. A study has shown that more patients are able to successfully instil drops into their eyes.²⁷ 

Communication and education

Studies have highlighted many barriers to successful adherence stem from patient education, communication and patient beliefs. It is thus paramount that patients are aware and appropriately educated on the disease process and risk for progressive and irreversible vision loss, and the benefits of current medical therapies. Simultaneously, such discussions should also address reasons for any patients’ issues with motivation and/or challenges relating to eye drop administration.^29,21

Preservative- free drops

Medication side effects can become a major barrier to treatment, especially if these are not well communicated to the patient at the outset. Whilst most patients can tolerate pressure lowering eye drops well, some may experience minor to significant allergic responses to particular ingredients.^15,31 Preservatives, particularly eye drops with benzalkonium chloride (BAK) may cause symptoms such as irritation, stinging and burning to the surface of the eye and lead to or increase dry eye disease.^31-40 

For patients who may have risk factors for developing ocular surface disease or dry eye, there may be preservative-free forms of glaucoma medications that may be more suitable for use.

Changing topical medication delivery mechanisms

Bottles vs single dose units (SDUs)

Some glaucoma drops are now available in single dose units and for some patients this is easier to instil. They are often also preservative free.

Gel forming eye drop

One pressure lowering medication is available as a gel-forming solution and preservative free eye drop. The gel allows for increased contact time with the eye reducing the dosing to less than other forms of timolol which are used twice per day.⁴⁶ Once daily dosing has the advantage of reducing ocular irritation and potentially improving medication adherence.

Potential methods for the future

Long lasting eye drug formulas have the potential to provide stable eye pressure control by requiring less frequent administration. Strategies like implants to provide longer-lasting delivery systems and could thus potentially improve adherence and help avoid traditional topical administration in the future.

References
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Original press release can be found here.