Abstract: Defocus theory is the mainstream theory of myopia prevention and control theory, from the initial animal researches and clinical trials to the current prevention and control methods (orthokeratology, defocus soft lens, defocus frame glasses, etc.) derived from this theory have all verified the importance of myopic defocus state of the peripheral retina in delaying the growth of the ocular axis. Among them, orthokeratology stands out with its predominant prevention and control effect, which is attributed to the more peripheral myopia defocus induced than other methods. Moreover, myopic defocus is mainly produced in the peripheral retina within the 10°~30° eccentric range ( it achieves the strongest prevention and control effect within 10°~20° eccentric range) and presents the asymmetric distribution of the temporal and nasal sides. Myopic defocus after orthokeratology is at its maximum on the first night and is stable after 1~12 months.(Int Rev Ophthalmol, 2024, 48:  443-447)

Key words: myopia, orthokeratology, peripheral retinal refraction