Establishing Consensus on the Appropriate Tool for Measuring Adherence to Glaucoma Medication in a Sub‐Saharan African Population: A Multidisciplinary Delphi–Based Study

ABSTRACT Background Despite the availability of various methods for assessing medication adherence, limited guidance exists regarding the most appropriate tool, particularly for measuring glaucoma medication adherence. Objective To achieve expert consensus on the appropriate tool for measuring glaucoma medication adherence using the Delphi technique. Methods A two‐round Delphi study was conducted with a panel of experts from diverse fields, assessing three validated adherence measurement tools. Consensus was determined using Kendall's Coefficient of Concordance. The extent of agreement and inter‐rater reliability were evaluated using the scale‐level content validity index (SCVI) and intraclass correlation coefficients (ICC), analysed in SPSS version 25. Results Sixteen experts (mean age 53.8 ± 7.1 years; mean professional experience: 21.9 ± 6.8 years) participated. Consensus levels of 81.0% and 89.0% were achieved in the first and second rounds, respectively. Agreement on non‐adherence characteristics was high (SCVI and ICC values > 0.75). The most appropriate tool for measuring non‐adherence to glaucoma medication was the Glaucoma Treatment Compliance Assessment Tool‐Short form (GTCAT‐S) with an SCVI of 0.91 and ICC of 0.94 (95% CI: 0.78–0.99; p = 0.001). Conclusions The GTCAT‐S was identified as the most suitable tool for measuring non‐adherence to glaucoma medication. It demonstrated a high SCVI and excellent inter‐rater reliability, indicating strong consensus among experts and robust measurement consistency.