If Acanthamoeba testing is unavailable locally, what immediate management is reasonable while arranging urgent referral?

It is always best to have a LOW threshold to initiate Acanthamoeba treatment. If you really suspect Acanthamoeba and have NO culture/PCR capability, I would recommend starting anti-Acanthamoeba therapy and getting the person to a cornea specialist who can confirm the diagnosis asap. Delay in treatment worsens outcome.

My present preference for starting treatment is PHMB 0.08% q1 hour. (Others may say any biguanide 0.04% or higher).

Obviously, no steroids. No CL use.

One exception to immediate initiation of PMHB is if you can get them in front of a cornea specialist within 24–48 hours; the referral center may want you to hold treatment so it doesn't reduce culture/smear yield, so call your referral cornea doctor (with confocal and culture/PC...