Well I say finally but there was a detailed description written in 1978 and like most great ideas it took decades to be an overnight success. 

 

The fungi and flora that usually live harmoniously on our feet (yum) under the right circumstances e.g. warm, dark footwear can develop into athlete’s foot and then start to invade the nail. There are three nail layers and the infection can be limited to the lower layers causing discolouration. Over time this can progress into the whole nail causing thickening and distortion of the nail. Topical application of anti-fungal treatments struggle to penetrate the nail.