Development and Validation of a Context-Adapted Dry Eye Disease Severity Classification System for Sub-Saharan African Populations

Existing dry eye disease (DED) classification systems, including the Dry Eye Workshop II (DEWS II) staging framework, were developed and validated in Western populations and may inadequately capture the clinical presentation of DED in sub-Saharan African contexts, where environmental exposures, ocular surface microbiome differences, and healthcare access patterns differ substantially. This study develops and validates a context-adapted DED severity classification system for sub-Saharan African populations using Nigeria as a primary research site. A sequential mixed-methods design will be employed across four phases: a systematic review of existing DED classification systems and their limitations in African populations; qualitative expert consensus workshops with Nigerian optometrists and ophthalmologists using the modified Delphi method; a cross-sectional validation study recruiting 600 DED patients from Lagos, Abuja, Kano, and Port Harcourt; and a longitudinal test-retest reliability assessment. The new classification system will integrate novel contextual indicators including environmental dust exposure scores, water access quality, and occupational UV exposure. Structural equation modeling will evaluate diagnostic validity. The resulting tool will be submitted to the African Vision Research Institute for peer review and will be piloted across Nigerian tertiary eye centers. This research represents an original theoretical and methodological contribution to global optometry and addresses a critical evidence gap in DED diagnostics for African clinical settings. Keywords: dry eye disease, classification system, sub-Saharan Africa, validation, ocular surface