Adaptive Fractional-Order Fuzzy Sliding Mode Control for Glaucoma Dynamics Regulating Intraocular Pressure and Optic Nerve Protection

This research investigates glaucoma, a leading cause of blindness marked by progressive optic nerve damage due to uncontrolled Intraocular Pressure (IOP). We propose a novel fractional-order model capturing the dynamic relationship between aqueous humor production, drainage efficiency, and optic nerve health. Through sensitivity analysis, three critical intervention points emerge: the aqueous humor inflow rate, baseline secretion levels, and the optic nerve's vulnerability to pressure-induced damage. Our findings suggest that prolonged IOP elevation triggers irreversible nerve degeneration, particularly when outflow pathways are compromised, whereas stable aqueous humor circulation helps preserve vision. To counteract disease progression, we design an Adaptive Fractional-order Fuzzy Sliding Mode Controller (AFFSMC) that precisely adjusts IOP by modulating aqueous humor dynamics and protecting neural tissue. Simulation results demonstrate that the AFFSMC reduces IOP fluctuation variance by 25% and achieves convergence within 3 seconds, while sensitivity analysis reveals that the aqueous humor inflow rate has the highest sensitivity index, identifying it as a primary therapeutic target.