Ideally the visiting eye team / surgeon should be seeing and operating on poor patients rather than middle class patients. If you are operating on middle class patients than you might be weakening any eye care infrastructure already available in that community. Depending on where you are working, the local ophthalmic surgeons might make their living serving the financial middle case. The poor can not afford to get into the health care system and the rich often have the option of jumping on a plane for USA, UK, Canada, etc. If you operate on their middle class patients, who they may have been following for years, then it might not be appreciated. None of us want to weaken the local ophthalmic infrastructure.
If you are operating in a low - income country with no ophthalmic care [ surgeons ] available, then this may not be a issue. But if you are operating in a middle - income country then you may be stepping on some ophthalmic toes by operating on the middle class patient. This is especially true if the patient then goes back to the local ophthalmologist for follow up care. You would not like this scenario in your home community.
It is often quite difficult to screen out the eye patients who are able to pay for eye care on the outside. The middle class patient, who might be a friend or family member of the local eye staff, is often good at getting in line when the North American surgical team shows up. The eye staff is often keen on seeing / treating the middle class patient as they can afford the operative cost.
This can be a tricky issue but if possible try to identify and operate on the poor [ needy ]. If you have a poor patient who really needs an eye operation but the local staff states he / she does not have the money, then offer to pay for the operation yourself. This often results in the staff waving the operative cost. Many poor patients will show up in their Sunday best to see you, so it can be difficult to judge their financial status. However most poor folks only have one pair of shoes, so looking at the shoes often helps determine the financial state.