Ophthalmology / Tanzania / Humans / Squamous Cell Carcinoma / Incidence / Clinical Sciences / Oral Squamous Cell Carcinoma (OSCC) / Optometry and Ophthalmology / Public health systems and services research / Retrospective Study / Clinical Sciences / Oral Squamous Cell Carcinoma (OSCC) / Optometry and Ophthalmology / Public health systems and services research / Retrospective Study