It allows puffs of smoke to escape enough to give you trichiasis.
Aetius (quoting from Leonidas) and Paul give very nearly the same account of the operation to remedy the trichiasis.
We know that granular ophthalmia with trichiasis as a sequela was very rife.
In cases of trichiasis where a few eyelashes turn in on the conjunctiva or cornea they may be removed by this method.
Albucasis recommends burning the roots of hairs in trichiasis with a probe of gold.
As a cautery it was used to destroy the roots of hairs, which had been removed for trichiasis.
trichiasis tri·chi·a·sis (trĭ-kī'ə-sĭs)
A condition in which the hair adjacent to a natural opening turns inward and causes irritation, as in the inward turning of the eyelashes upon the eye.