The Impact of Adherence and Instillation Proficiency of Topical Glaucoma Medications on Intraocular Pressure

Abstract

Background: The possible sequel of poorly controlled intraocular pressure (IOP) includes treatment failure, unnecessary medication use, and economic burden on patients with glaucoma.

Objective: To assess the impact of adherence and instillation technique on IOP control.

Methods: A cross-sectional study was conducted on 359 glaucoma patients in Menelik II Hospital from June 1 to July 31, 2015. After conducting a Q-Q analysis, multiple binary logistic analyses, linear regression analyses, and two-tailed paired t-test were conducted to compare IOP in the baseline versus current measurements.

Results: Intraocular pressure was controlled in 59.6% of the patients and was relatively well controlled during the study period (mean (M) = 17.911 mmHg, standard deviation (S) = 0.323) compared to the baseline (M = 20.866 mmHg, S = 0.383, t (358) = -6.70, p < 0.0001). A unit increase in the administration technique score resulted in a 0.272 mmHg decrease in IOP (p = 0.03). Moreover, primary angle-closure glaucoma (adjusted odds ratio (AOR) = 0.347, 95% confidence interval (CI): 0.144-0.836) and two medications (AOR = 1.869, 95% CI: 1.259-9.379) were factors affecting IOP.

Conclusion: Good instillation technique of the medications was correlated with a reduction in IOP. Consequently, regular assessment of the instillation technique and IOP should be done for better management of the disease.

Figure 1

Level of intraocular pressure by the duration of taking glaucoma medications in Menelik II Hospital, 2015. ^∗Outliers.

Figure 2

Profile of diagnosis of glaucoma among patients attending the glaucoma clinic of Menelik II Hospital, 2015. ^∗Ocular hypertension, juvenile glaucoma.

Figure 3

Percentage of practice of eyelid closure and nasolacrimal route occlusion among patients attending the glaucoma clinic of Menelik II Hospital, 2015.

Figure 4

Comparison of the percentage of controlled intraocular pressure in the left, right, and both eyes among glaucoma patients in Menelik II Hospital, 2015.

Figure 5

Relationship of intraocular pressure with the type and number of medications among glaucoma patients in Menelik II Hospital, 2015. (a) By the number of medications; and (b) by the type of medications.

Figure 6

Factors associated with controlled intraocular pressure among patients attending the glaucoma clinic of Menelik II Hospital, 2015. The following factors were used in the logistic regression model: age, sex, marital status, ethnicity, educational level, residence, religion, occupation, monthly family income, type and severity of glaucoma, duration of the glaucoma in years, duration of taking medications in years, average follow-up period per year, the presence of previous surgery or laser treatment, major comorbidities, side effects of medications, acquisition of the medications (free of charge or not), financial problem to purchase the medications, the presence of other types of eye drops, adherence towards the medications, and instillation proficiency of the eye drops. The factors were assumed statistically significant at p < 0.05 and the end of the bar graph shows the odds ratio. PACG: primary angle-closure glaucoma; PEG: pseudoexfoliative glaucoma; POAG: primary open-angle glaucoma. ^∗Secondary glaucoma, ocular hypertension, normal tension glaucoma, juvenile glaucoma ^∗∗latanoprost; pilocarpine; timolol and latanoprost; timolol with other types of eye drops; pilocarpine with other types of eye drops; latanoprost with other types of eye drops; timolol, latanoprost, and pilocarpine; timolol and latanoprost with other types of eye drops; timolol and pilocarpine with other types of eye drops.