<p>Conjunctivitis or pink eye disease is an acute and highly contagious infection that spreads rapidly through direct human contact and environmental irritants. To better understand and effectively control its spread, this research introduces a refined mathematical model that captures both direct and irritant-induced transmission pathways along with quarantine–treatment dynamics. It also offers a comprehensive analytical and numerical framework that guarantees model stability, sensitivity, and optimal control analysis. Theoretical results establish boundedness, positivity, and stability conditions for the equilibria, specifically determining the parameter ranges that lead to disease eradication and persistence. Sensitivity analysis identifies that irritant-related transmission contributes significantly to disease persistence, while quarantine–treatment measures effectively reduce disease prevalence. Furthermore, we formulate an optimal control problem that incorporates time-dependent disease control strategies aimed at minimizing direct contact through preventive measures, reducing environmental exposure, and facilitating quarantine-treatment efforts. Numerical simulations performed for three different cases demonstrate that the integrated control approach is the most effective and sustainable, producing substantial reductions in infections and sources of environmental irritants. In general, this work improves the reliability of conjunctivitis modeling by addressing analytical and computational limitations in previous studies and provides actionable insights for public health planning.</p>