Question: I need some help with CPT code 68840. Is this billed bilaterally, with modifiers -RT and -LT, or should I code it for the upper lid and lower lid of the same eye?
Answer: If the ophthalmologist probed both eyes, then yes, you would bill bilaterally, 68840-50 (Probing of lacrimal canaliculi, with or without irrigation; bilateral procedure) for Medicare, and 68840-RT (... right side) and 68840-50-LT (... bilateral procedure; left side) for private payers. Be advised, though, that those carriers with Local Coverage Determinations (formally LMRPs) state that if the indications to perform the procedure on both eyes are not clearly documented, they may reduce coverage to a unilateral payment.
The payment for 68840 is allowed per eye, not per lid, so you will not be able to use the eyelid modifiers - E1 (Upper left, eyelid), E2 (Lower left, eyelid), E3 (Upper right, eyelid) or E4 (Lower right, eyelid) - in this case to try to get paid for both eyelids. Always keep in mind that carriers other than Medicare have different coverage and payment policies and it might be worth a try to use the E modifiers along with modifier -51 (Multiple procedures) to bill for multiple punctums, using the same principles as billing punctal plug closure.