The severity of the diseased nail is related to the clinical classification of nail fungal disease. 1972 Zaias divided nail fungal disease into three types: white superficial nail fungal disease, proximal subxiphoid nail fungal disease, and distal subxiphoid nail fungal disease. In addition to the above three types, there are also total nail dystrophy type nail fungal disease and nail fungal disease. For PSO and TDO, the severity of diseased nail is obviously heavier than that of DLSO, SWO and EO because the patient’s nail root is involved. The growth rate of the nail plate The growth rate of the nail plate is closely related to the location of the diseased nail and the age of the patient. The growth rate of the index, middle and ring finger nails is the fastest, about three times that of the thumb nail, while the growth rate of the thumb nail is similar to that of the 2-4 toe nails, both 1.5 times that of the thumb toe nail. Their average growth rate is 0.1 mm per day, and the specific growth rate varies depending on the individual’s age, metabolic rate, season, etc. Fingernails take 4-6 months to regrow from scratch, while toenails take 12-18 months due to slower growth. There are also significant differences in the growth rate of nails in different age groups: before the age of 25, the nail growth rate is the fastest; between the ages of 30-60, the growth rate decreases by 20-30%; by the age of 80, the nail growth rate can be reduced by 50%. The speed of fungal invasion The length of time to cure nail fungal disease depends on the difference between the growth rate of the nail plate and the speed of fungal invasion. In the absence of treatment, if V1>V2, the lesion will heal itself; if V1=V2, the lesion will remain stationary; if V1