There are 2 simple reasons why steroid injections are rarely used to treat chalazia.
1. They often don't work.
2. They cause an initial increase in the eyelid swelling. This makes the patient feel worse, because extra fluid and pressure within the chalazion increases discomfort and makes the eyelid feel heavier.
Let's take a step back.
What are chalazia?
These are lumps within the eyelid caused by blockage of the oil gland(s) (Meibomian glands), and retention of oil that should normally be secreted into the tear film.
This retained oil can cause inflammation, and/or just build up over time into a pocket of mush that has the consistency of toothpaste.
Any particular 'chalazion'/eyelid lump, could be mainly inflammatory swelling, mainly retained oily paste, or some combination of the above. It's not always possible to tell which is which.
Now, steroids do a few things, but their main action is to reduce inflammation. If a person happens to have a lump mainly caused by inflammation, steroids might work. More often than not, especially when it is chronic or large, there is quite a bit of oily paste inside and the steroid doesn't do much for this.
Perhaps one steroid injection might give a 50-50 chance of improvement for a chalazion. Sometimes repeated injections can give a higher chance of success with this method. Doing an incision and drainage will give a better than 95% chance of cure.
Personally, I would prefer having 1 procedure and be done with it, rather than getting a poke + increased swelling and then wondering whether the thing will really go away or not. And then maybe after wondering for a few weeks then finally undergoing the incision and drainage anyway.
