Descemet membrane detachment (DMD) is a condition often observed post-cataract surgery, where the Descemet membrane, a thin layer of cells lining the back of the cornea, detaches from the corneal surface. This detachment disrupts the balance of aqueous humour which is crucial for maintaining intraocular pressure and nourishing ocular tissues, potentially affecting ocular health. The present research aims to study the aqueous humour flow under the influence of external heat sources during DMD. A mathematical model of buoyancy-driven aqueous humour flow is developed to analyse the behaviour of the fluid as it flows through the pupil aperture in the anterior chamber during DMD when exposed to external heat sources. The finite element method, implemented through COMSOL Multiphysics, is used to simulate the movement of fluid under normal thermophysiological conditions and during exposure to external heat sources. Results show that the reattachment of DMD may occur as the behaviour of AH varies with the amount of heat exposure. This research holds paramount significance in the field of ophthalmology due to its potential to provide critical insights into the complex interplay between aqueous humour dynamics and DMD under external heat exposure.