Is it permissible for the patient to provide the kohl material to the oculist?

Primary text

It is permissible if the kohl material is provided by the patient (the one hiring), as the implements used in the work are typically the responsibility of the hirer, analogous to bricks in construction or milk in breastfeeding. The custom supports this arrangement, as procuring the material may be difficult or impossible for the ailing person, similar to dye for a dyer or ink for a scribe.