Abstract: Schlemm canal is a circular tubular structure surrounding the trabecular meshwork around the limbus, which has a different morphological changes ( diameter and area ) in different states and different quadrants. For example, the study showed that the diameter and area of Schlemm canal decreased significantly with age, and the nasal side of Schlemm canal area was greater than the temporal side in normal adults. However, the diameter and area of Schlemm canal in high myopia were significantly larger than that of the normal control group, and the area of Schlemm canal in glaucoma patients was significantly smaller than that of normal subjects. As an important part of the aqueous drainage channel, the measurement of Schlemm canal morphological parameters has been paid great attention by researchers. The measurement methods have been developed from light microscope and electron microscope to ultrasound biological microscopy and optical coherence tomography. Previous studies have reported that the parameters of Schlemm canal in glaucoma patients was significantly smaller than that of normal subjects, as well as glaucoma treatment, such as medication, laser and surgical, can alter the microstructure of the Schlemm canal. (Int Rev Ophthalmol, 2025, 49:  1-7)

Key words: glaucoma, Schlemm canal, intraocular pressure