Compliance with Medical Management in Glaucoma (continued)

Granström identified 3 different deviations from the prescribed treatment in a study of 15 non-compliant patients using pilocarpine eyedrops 3 times daily:¹⁴

• inadequate spacing of doses during the day, with long intervals at night
• omitting the midday dose
• long interruptions in medication.

The number of missed doses reported by interview was inaccurately low when compared with the monitor reading (table 3), and 11 patients reported tailoring the doses to lifestyle events such as meal or sleep times. While the inaccuracy of the interview technique was highlighted, discussion with patients may be valuable in determining the most convenient times for medication. In this way, the ophthalmologist may be able to assist the patient to minimise lifestyle disruption, thereby facilitating compliance.

Table 3. Number of missed doses during 7 days according to interview and monitor data¹⁴

* Lost to monitor records; no interview obtained.

Rotchford and Murphy found that 24% of 86 patients admitted to omitting their glaucoma treatment either frequently or occasionally.¹⁵ Patients who always took their eye drops were significantly more likely to regard their drops as being 'vital' to their treatment as opposed to 'important'. The 13 patients registered as blind or partially sighted reported never missing a dose.

Physical inability to administer drops to the eye may have a role in visual loss that is additive to other aspects of noncompliance.¹⁶ Winfield et al. performed a study to elucidate the physical difficulties experienced by 200 patients during eye drop administration.¹² 57% of patients had some difficulty administering their drops with 21% always needing assistance. Fear of the dropper touching the eye resulted in patients holding the dropper too far away, making the aim difficult and encouraging the blink reflex (table 4). Older patients, particularly those with arthritic conditions, had difficulty in physically administering eye drops. Interestingly, since patients were reluctant to discuss these difficulties with their doctors, the medical staff involved in their care were largely unaware of the problems associated with eye drop administration. Dyscompliance is even less recognised than non-compliance.

Complex regimens are suspected to be a cause of non-compliance in terms of both number of medications and number of daily doses. Since glaucoma patients are often prescribed multiple medications and may have concomitant therapy for other chronic diseases, they may be at high risk for non-compliance.

Table 4. Problems encountered during self-administration of eyedrops¹²

Strategies for Improving Compliance

A major factor in the medical management of glaucoma is the extent to which patients comply with the treatment regimen.^10,17 Progression of the disease often leads to more potent drugs being given, which may be inappropriate if the progression is due to non-compliance rather than to treatment failure.^14,17 In addition, necessary glaucoma surgery may be postponed if non-compliant patients have a low IOP at clinic visits as a result of taking the medication only during the preceding hours.¹⁴

Strategies to improve compliance include educating patients about the disease and its treatment combined with tailoring the therapeutic regimen to the patient's lifestyle.¹⁷ Patient education measures may take the form of videos, booklets, drug schedule diaries, and nurse education, with review and reinforcement at clinic visits. It is also important to work with patients to ensure that eye drops are correctly administered.

The usefulness of a 6-minute videotape in educating 98 patients with glaucoma about their disease was evaluated by Rosenthal et al.¹⁸ A questionnaire, used to determine how much patients remembered from the video, showed that patients knowledge was significantly improved immediately after viewing (p < 0.001). After 6 months, patients with glaucoma retained more knowledge of the disease than did the controls who did not have glaucoma, although there was a significant drop in knowledge from immediately after viewing (p < 0.001). Patients responded positively to seeing the film and were grateful for the opportunity to view the tape. Provision of an accompanying brochure for the patient to take home may help to solve the problem of recall after time.

Streamlining a regimen to the patient's lifestyle is important to improve compliance, and once- or twice-daily medication interrupts patients' lifestyles far less than more frequent dosing.¹⁷ Tailoring a medication to lifestyle requires investigation of patients' routines such as sleeping and eating patterns and work routines, and selecting a medication that will work well with these regular habits.¹⁷

Studies comparing fixed combination dorzolamide and timolol with timolol plus pilocarpine given concomitantly found that patients preferred the combination by a ratio of 4 to 1 (p < 0.001).¹¹ One of the main reasons given was that the combination interfered significantly less with daily life in terms of activity limitations and side effects. Compliance was also significantly better with the combination.

Similarly, Schenker et al. found that significantly more patients (71 %) preferred timolol gel once daily to timolol solution twice daily (p < 0.001), with 92% giving the once-daily dosing regimen as the reason for their preference.¹⁹ Patients also reported significantly fewer missed doses while using timolol gel (p = 0.005), suggesting that, when appropriate, patients appreciate having their therapy simplified.

Latanoprost has a once-daily dosing schedule and has been shown to decrease IOP as much or greater than other glaucoma medications.²⁰ This agent, therefore, may be substituted for one or more glaucoma drugs to simplify the dosing schedule. Smith et al. found that 43 of 61 patients (70.4%) effectively simplified their daily medication without an adverse effect on IOP by switching to latanoprost (table 5).²¹ These researchers concluded that latanoprost may be used to simplify the regimen for glaucoma patients by reducing the number of doses per day while maintaining an appropriate IOP level.

Other measures to improve compliance include more complete labelling of medicines, increased supervision and counselling, medication calendars, and reduction of medication-induced side effects.⁶ The use of different sizes or shapes of medications and their containers will help patients to discriminate between different treatments⁸ and obtaining help from a family member may improve compliance.¹⁷

Table 5. Number of patients and daily glaucoma medication dose before and after switching to latanoprost (n = 43)²¹

In Conclusion

There are a number of reasons for poor compliance with glaucoma medications, including lack of understanding of the disease, no obvious symptoms, complicated or too frequent drug schedules, side effects, physical difficulty in administering eye drops, and cost. Simplification of the treatment regimen and interactive health education appear to be the most important factors for improving compliance.⁵ In addition, modifying the treatment regimen to fit with a patient's lifestyle may promote compliance by diminishing adverse effects while achieving maximal benefit.⁹