I see more seedy toe than I should in this day and age. I see lots of horses with such chronic conditions that I have to take off sometimes a third of the hoof wall to tackle the necrotic area in which the fungus has spread. This should be addressed much sooner when it first appears, which is usually at the toe. It's no good just poking a nail up inside the wall to clean it out and spraying purple spray. The wall needs to be debrided and all the infected area cut back to healthy tissue.
Below is a stabilised hoof post keratoma removal. Farriers will possibly see only one or two keratomas in their career, I can see five or six a year and because of this can recognise them and am experienced in their removal.