Compliance to atropine for myopia progression and its socioeconomic and behavioral determinants

Dear Editor, Myopia is a refractive error in which the optical power of the eye is too strong for the corresponding axial length. There has been a significant increase in the prevalence of myopia over the past decades.[1] Currently, low-concentration atropine (LCA) is the most established myopia control strategy (MCS).[2–4] It is believed that it acts on muscarinic receptors present in the sclera to prevent the elongation of the eyeball.[5] The course of treatment is expected to be a minimum of 2 years,[6] with daily instillation of eye drops. Prolonged nature of the therapy necessitates strong patient and parent education and counseling. To date, very limited data exist on compliance to LCA. The only study evaluating compliance to LCA, measured by self-reporting with forms, reported 71.4% patients complying at the end of 6 months with a sample of 27 patients.[7] We conducted a prospective observational study at Aravind Eye Hospital, Chennai (May 2023 to May 2024) to assess the compliance to LCA and evaluate the influence of socioeconomic background and beliefs about medications on adherence to therapy. MCS-naive patients aged 5–15 years with documented progressive axial myopia (≥0.5D/year progression) were included. Patients who had undergone prior ocular surgery; had a history of keratoconus, visually significant corneal scarring, cataract, macular pathologies, amblyopia, strabismus, retinopathy of prematurity or glaucoma; or had a history of using any specific therapy for myopia control were excluded from the study. The patients’ demographic and socioeconomic data were recorded and classified using the Modified Kuppuswamy Scale, adjusted for 2023 (MKS-23).[8] The parents’ beliefs were captured using the 18-point “Beliefs about Medicines Questionnaire” (BMQ).[9] The BMQ is a questionnaire with eight general (BMQ-General) and ten specific (BMQ-Specific) points to assess the behavior of parents of patients toward medication. The BMQ-General consists of General-Harm and General-Overuse subscales, and BMQ-Specific consists of Specific-Necessity and Specific-Concerns subscales. BMQ was selected as a measurement tool as it is a non-disease-specific tool developed to assess beliefs about different medications in different illnesses[10] and has been used for a variety of diseases, including eye diseases such as glaucoma.[11] The patients were initiated on therapy after counseling and asked to follow up after 6 months. Self-reported compliance was assessed. Patients who used the drops for >90% of prescribed days were considered compliant.[4,7] 93 patients (48 male) aged 11.93 ± 2.51 years were analyzed. 21 were upper class, 37 were upper-middle class, 23 were middle class, and 12 were lower-middle class. 78 patients (83.87%) were compliant to treatment. All compliant patients’ self-reported compliance was 100% of the prescribed days. All noncompliant patients did not use the drops at all. All noncompliant participants were from either middle (8) or lower middle (7) socioeconomic class. Lower education of head of family, lower family income, lesser nature of work of head of family, lower socioeconomic strata, lack of belief regarding necessity of LCA, stronger concerns regarding side effects of LCA, and more general concern about harm from medicines were independent significant predictors for noncompliance [Table 1].Table 1: Comparison of evaluated parameters between compliant and noncompliant participantsHigher scores on family income correlated with significantly better understanding of the necessity of LCA. Higher occupation score correlated with significantly better understanding of necessity and fewer concerns regarding LCA, and lesser concerns regarding harms from medications in general. Higher education score correlated significantly with lesser concerns about LCA and medication overuse by doctors [Table 2].Table 2: Correlation between subscales of Modified Kuppuswamy scale (adjusted for 2023) and subscales of the Beliefs about Medication questionnaireThe landmark ATOM[4] (>95%) and LAMP[2] (>90%) trials reported very good compliance to LCA in all their study arms. However, they did not include noncompliant patients for analysis. Most patients were compliant to LCA in our study. The only Indian study evaluating compliance reported 27 patients had around 70% patients’ compliance by self-reporting but did not assess any underlying factors influencing compliance patterns.[9] Lower socioeconomic status and beliefs about medication significantly influenced compliance to LCA in our study. Both factors have been demonstrated to be significant predictors for adherence to medication for multiple diseases, such as glaucoma,[12,13] depression,[14] asthma,[15] and hypertension,[16] among others. Lower socioeconomic status was significantly (P < 0.00001) associated with noncompliance. Lower education (P < 0.00001), occupation (P < 0.00001), and family income (P < 0.00001) all were independently significant for noncompliance. Higher cost of medications and lower educational background have been associated with lower compliance for ophthalmic diseases requiring topical therapy.[17] This may have affected their ability to purchase medication and adversely affected compliance. Specific concerns (P < 0.00001) and doubts about necessity (P = 0.0025) of LCA as well as a general feeling about harmfulness (P = 0.009) of medications were independently significant for noncompliance. Belief systems have been shown to affect compliance in diseases requiring topical[12,13] or systemic[14–16] therapy. It may be possible to improve compliance by targeted counseling, which has been shown to be a successful strategy among patients on medication for glaucoma[18,19] as well as systemic diseases.[20] There was a significant correlation of socioeconomic status with beliefs [Table 2]. A higher socioeconomic status results in increased access to healthcare and education, which may affect beliefs about medication. More effort may be directed toward counseling patients from relatively lower socioeconomic strata. Forgetfulness[21] of parents, as a result of socioeconomic and behavioral determinants, may possibly be the common pathway for noncompliance to LCA. The only eye disease extensively studied for compliance to drops is glaucoma. The leading cause of missed drops in patients with glaucoma is forgetfulness,[21] which may have been the major underlying factor in our study population as well. Concerns such as knowledge about the disease and disease course have been shown to decrease compliance,[22] but these were potentially addressed by counseling at initiation of therapy. Single daily dosing of LCA is unlikely to decrease compliance due to difficulty in understanding drug application regimens,[23] and application by parents would likely negate the effect of difficulty in applying drops as a potential modifier.[23] No patients had any LCA-related adverse effects, and thus, their impact on compliance would be highly unlikely.[24] However, as these specific variables were not evaluated systematically, the reasoning is largely speculative. Our study was limited in that compliance was measured by self-reporting, which may have overestimated the compliance to LCA. Beliefs of only one parent who came with the child for the first visit were assessed, instead of both parents. There was unequal distribution of patients among different socioeconomic strata, which may not reflect the entire patient population accurately. Reasons for noncompliance were not specifically inquired for, and the patients were not followed up over the entire duration of treatment. We conclude that socioeconomic and behavioral factors significantly influenced compliance. Targeted counseling addressing specific concerns regarding LCA and medications in general as well as emphasizing the necessity of LCA may help improve patient compliance, especially in patients from lower socioeconomic strata. Further investigation into compliance of different MCSs and methods to improve compliance are needed to enable optimal utilization of preventive therapies against myopia progression. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.