Retinal ganglion cells are closely related to visual function. Retinal ganglion cell apoptosis and axonal injury can be found in many blinding eye diseases, such as primary glaucoma, optic neuritis, diabetic retinopathy, and atrophic age-related macular degeneration. Ganglion cells mainly exist in the retinal nerve fiber layer, the ganglion cell layer and the inner plexiform layer of the macular area. These three structures are collectively referred to as the retinal ganglion cell complex, and change of the thickness reflects the state of the retinal ganglion cell. It has been reported that ganglion cell complex thickness is thinner in the injured retinal ganglion cells. Therefore it is important to detected thickness of retinal ganglion cell complex in the diagnosis of ocular disease and the evaluation of its severity and prognosis. In this paper, we reviewed the recent progress in the detection of retinal ganglion cell complex thickness in various eye diseases to assist the early diagnosis, treatment and evaluating prognosis of associated ophthalmopathy.