Ophthalmology and Optometry Coding Alert

Check the Medicare fee schedule for important bilateral coding guidelines for 673xx.

Coders — especially those for pediatric ophthalmologists — know how difficult sorting out the various eye muscles involved in strabismus surgery can be. With 12 ocular muscles to keep track of, one simple coding mistake could cost your practice hundreds, unless you know the ropes.

Let Modifier 50 Spring You From 67312 Trap

Scenario: An ophthalmologist removes a 6.5-mm section of the lateral rectus muscle of the patient’s left eye and resects the muscle to strengthen it and correct strabismus. He then repeats the procedure on the right eye, again removing 6.5 mm of the lateral rectus muscle and then resects it. Two different codes may tempt you — but only one will bring you the reimbursement you deserve.

Be careful: Because the ophthalmologist performed a resection procedure on two horizontal muscles, 67312 (Strabismus surgery, recession or resection procedure; two horizontal muscles) may look correct, but don’t fall into this trap.

The strabismus surgery codes (67311-67318) describe unilateral procedures or procedures performed on one eye only. Although the surgeon did resect two muscles, they were in different eyes, so 67312 is not correct. Instead, you should report 67311 (Strabismus surgery, recession or resection procedure; one horizontal muscle) bilaterally. Most Medicare carriers want you to report the entire session on one line with modifier 50 (Bilateral procedure) and a “1” in the units field.

Warning: Reporting 67312 would hurt your reimbursement in this case, and it is really an incorrect code to use for the services that were performed. In the Medicare physician fee schedule, 67311 has a “1” bilateral status indicator. That means Medicare expects you to report bilateral services and will process them for payment. You can use modifier 50 for that particular code and expect to receive 150 percent payment.

If you report 67311-50 or two instances of 67311 on two lines — for example, 67311-LT for the left eye and 67311-RT-51 (Multiple procedures) for the right — Medicare will base payment on 150 percent of the fee schedule amount for a single code.

Medicare multiplies the relative value units (RVUs) for 67311 (18.43) by the conversion factor of 34.023, arriving at $627.04. Appending modifier 50 for the bilateral procedure means that Medicare would reimburse you 150 percent of that, giving you $940.56 (unadjusted for geographical location).

Reporting 67312, however, even though the descriptor mentions “two horizontal muscles,” will short-change you. With no bilateral pay adjustment, the RVUs for 67312 would only bring in $755.31. 

Bottom line: Code 67312 is also an incorrect code to report since it implies that two horizontal muscles in the same eye were resected, and that was not the case.

Select a Single Code for Single-Eye Muscles

To code strabismus surgery correctly, you also need to know when you should or should not appropriately report strabismus surgery bilaterally.

If the ophthalmologist recesses both the lateral rectus and medial rectus muscles of the left eye, it is not a bilateral procedure. This is a case for which 67312 would be appropriate. You would report 67312 when two horizontal muscles are recessed or resected in the same eye. The same rules apply for the vertical muscles (the superior rectus, inferior rectus and inferior oblique muscles).

Use these CPT^® codes for the following strabismus scenarios, based on which muscles the ophthalmologist worked on:

• 67311 for one horizontal muscle in one eye
• 67312 for two horizontal muscles in one eye
• 67314 for one vertical muscle in one eye
• 67316 for two or more vertical muscles in one eye
• 67318 for the superior oblique muscle in one eye.

If the ophthalmologist operates on one vertical and one horizontal muscle in one eye, however, it is correct to use two codes — 67311 and 67314 (... one vertical muscle [excluding superior oblique]).

Practice: So how would you code if your ophthalmologist operates on both horizontal muscles in the left eye but only one horizontal muscle in the right eye? Use 67312-LT (for the two muscles in the same eye) and 67311-51-RT (for the single muscle in the right eye). Reporting 67311 bilaterally for the horizontal muscles in both eyes would not be correct.

Save Add-On Code for Special Occasions

You should use add-on codes whenever the operative report clearly documents an additional procedure — an adjustable suture, for instance — or a complicating condition or history.

A careful coder may be aware of a condition in the patient’s history that the surgeon doesn’t state in the operative report. You should call this fact to the physician’s attention so that he can edit it in the operative report to allow billing.

Requirement: You can only report all add-on procedures and services — those CPT^® codes preceded by a “+” — when you also report another code, representing the primary procedure.

For example, you can use +67320 (Transposition procedure [e.g., for paretic extraocular muscle], any extraocular muscle [specify] [List separately in addition to code for primary procedure]) with strabismus surgery codes 67311-67318, according to CPT^® guidelines.

Likewise, you can only report the following add-on codes when applicable with codes 67311-67318:

• +67331 — Strabismus surgery on patient with previous eye surgery or injury that did not involve the extraocular muscles
• +67332 — Strabismus surgery on patient with scarring of extraocular muscles or restrictive myopathy
• +67334 — Strabismus surgery by posterior fixation suture technique, with or without muscle recession.

Don’t overlook: You can report +67335 (Placement of adjustable suture[s] during strabismus surgery, including postoperative adjustment[s] of suture[s] [List separately in addition to code for specific strabismus surgery]) and +67340 (Strabismus surgery involving exploration and/or repair of detached extraocular muscle[s] [List separately in addition to code for primary procedure ]) not only with strabismus-surgery codes 67311-67318 but also with add-on codes 67320-67334.

But you can only report 67320-67334 with a primary procedure code. Many trauma cases may involve multiple add-on codes — for instance, in the case of an open globe in which the ophthalmologist would have to explore for damaged muscles and insert an adjustable suture.

Watch out: The bilateral status is different for the six strabismus add-on codes. Their bilateral status of “0” means that the 150 percent payment adjustment for bilateral procedures does not apply. It is not correct to use modifiers LT/RT or 50 with these add-on codes.