So, a steroid is usually used to help reduce swelling. If we are seeing something like a small infection, it may be that the topical antibiotic was not strong enough to get rid of the infection if it was internal (like from a bite or sing to the eyelid), instead of to the eye itself (like conjunctivitis).
Similarly, if she's had a scratch to the eye, a steroid can cause that to get worse, rather than better (hopefully your vet stained her eye to check for scratches or tears before giving the ointment).
I think an ophthalmologist is an excellent idea just due to the location, because it if does turn out to be swelling due to a laceration or ulceration of the eye itself, they are going to be best equipped to deal with it.
If this IS an abscess or bite wound just under the eye (which can happen quite frequently), it may simply be that a round of oral antibiotics and injectable steroids may be the better option for Sophie, since the ointment isn't really going to do much good in the case of a near-eye abscess.
Similarly, if this is a small lump (at her age, it would be highly unlikely for this to be something malignant), the ophthalmologist will be the best person to look at it, since they may want to stick a tiny needle in there and collect cells to determine what type of tissue makes up the bump (depending on how close it is to the eye itself).
It is absolutely possible that this could be something simple like a cherry eye, which is just the prolapse of the third eyelid, and is often just a cosmetic issue. They tend to look like this: http://www.petmd.com/dog/conditions/eyes/c_multi_prolapsed_gland, and are EXTREMELY common in dogs. The vets can tack these back and keep them from slipping out again, but they are in no way a serious condition of the eye.
It sounds like you are making the right steps here in heading into a specialist, and I do not think you have anything that you need to worry about in regards ***** ***** seriousness of her condition, such as it causing blindness or the loss of an eye. The conditions that might cause severe signs would be extremely rare and unlikely in a dog her age.
Did you have any additional questions?