Abstract: From the fluid mosaic model to lipid rafts, the structural model of the cell membrane has been updating continuously. The cell membrane fluidity refers to the movement of lipid and protein molecules that construct the cell membrane together. Nowadays, there are several methods of fluidity observation through different mechanisms, such as spin labeling electron paramagnetic resonance and various fluorescent probes. The interaction of certain soluble proteins with the cell membrane can also alter its fluidity and other properties. For the lens cell membrane, there has been only limited research on its fluidity. The particular composition of lipids in lens cell membrane implies the special nature of its fluidity. As age is increasing, the fluidity of lens membrane changes accordingly, leading to the establishment of the diffusion pathways among the cells in the nuclear region, and the formation of syncytial ultrastructure. The analysis of the fluidity of lens cell membrane will be helpful in the future for further clarifying the pathogenesis of cataract.  (Int Rev Ophthalmol, 2013, 37: 19-24)