Question: Our ophthalmologist resected the lateral rectus muscles of both of the patient’s eyes during a strabismus surgery and marked 67312 (Strabismus surgery, recession or resection procedure; 2 horizontal muscles) in the op note, but our office manager said that was incorrect. Can you advise? Codify Subscriber Answer: The strabismus surgery CPT® codes (67311-67318) describe unilateral procedures, or procedures performed on one eye only. Although the surgeon resected two muscles total, they were in different eyes, so 67312 is not correct. Instead, you should report 67311 (Strabismus surgery, recession or resection procedure, 1 horizontal muscle) bilaterally. In most cases, you can do this by appending modifier 50 to the procedure code. Watch Out: Depending on the payer, bilateral procedures are reported differently for outpatient procedures than they are for in-office procedures. Be sure to report bilateral procedures according to the modifier instructions provided by each of your payers. Don’t Do This: One common reason for rejections of bilateral claims? “Claims often list codes with the modifier 50, but then only bill for one side,” says Rhonda Buckholtz, CPC, CPCI, CPMA, CEDO, CRC, CHPSE, COPC, CENTC, CPEDC, CGSC, vice president of strategic development for Eye Care Leaders. Also, make sure the procedure code is not inherently bilateral, she notes. Bullet list and source quote adapted from Eye Care Leaders Magazine (Fall 2016).