The uncompressed GUV is at equilibrium with zero membrane tension (Σ). As the compression is initially applied, the area per lipid and lateral membrane tension increase temporally. As the volume (V) is reduced, water is forced out of the vesicle until it reaches equilibrium in the final state and the tension returns to zero. While the final vesicle surface area (A) has not changed compared to the uncompressed state, the domains are now more restricted in one axial dimension due to the new geometry of the compressed oblate vesicle causing a reduction in the inter-domain distance (r) for a population. Moreover, during the transient non-equilibrium intermediate state, the increased membrane tension favours domain fusion in order to decrease the total line energy (E) and lower the total free energy.