Pop Quiz: Know Your Modifiers

A few practice questions on modifiers will sharpen your game.

By Joy Woodke, COE, OCS, OCSR

A working knowledge of coding modifiers will help retina practices code and bill services accurately and effectively, maximizing reimbursement while minimizing the risk of an audit. Choosing the correct modifier to append to a service becomes easier with practice. In this article, I explore two types of modifiers and present pop quizzes to test your new knowledge.


Modifiers are necessary for proper coding and reimbursement for services, including testing services, surgical procedures, and office visits. Modifiers are appended to office visits and surgical codes and are listed in Table 1; modifiers may also be appended to diagnostic testing services, a topic that will be explored in a future article.

The global period of a procedure—which identifies it as a major or minor surgery—must be known when selecting a modifier for an office visit.


The most commonly used modifiers for office visits are -24, -25, and -57. Their definitions are as follows:

Modifier -24: Unrelated evaluation and management service (or eye code) by the same physician during postoperative period; or office visit in the postoperative period not related to the original surgery (eg, new symptoms, significant changes in eye health requiring an evaluation of an unrelated problem or fellow eye).

Modifier -25: Significant, separately identifiable evaluation and management service (or eye code) by the same physician on the same day of the procedure or other services; or office visit on the same day as a minor surgery (0- or 10-day global period).

Modifier -57: Decision for surgery, major procedure; or office visit, same day or within 3 days of a major surgery (90-day global period).

Pop Quiz

After undergoing panretinal photocoagulation laser treatment in the left eye, a patient is seen during the postoperative period for a new visual distortion in the right eye.

The patient is diagnosed with a retinal tear with multiple breaks in the right eye.

What is the correct modifier to use when coding this case?

Correct Modifier: -24

Reason: The new symptom is in the unoperated eye, and evaluation would be considered unrelated to the original procedure.


Specific modifiers are used when coding surgical procedures. The most common modifiers for retina surgical coding are -58, -78, and -79. Refer to Table 2 to learn the differences.

Understanding whether a patient visit is related to the original procedure is one of the chief factors in choosing the appropriate modifier.

Pop Quiz

During the global period of a retinal detachment repair with silicone oil fill in the right eye, a patient is scheduled for an unplanned removal of silicone oil. For coding purposes, the diagnosis is a mechanical complication due to another implant and internal device. A pars plana vitrectomy is performed.

What is the correct modifier to use when coding this case?

Correct Modifier: -78

Reason: This was an unplanned return to the OR, and the second procedure was related to the first one.

Pop Quiz

During the global period of a repair for a detached retina in the left eye, a patient presents with a BB gun pellet in the same eye. The patient is diagnosed with an intraocular foreign body and undergoes surgery for its removal.

What is the correct modifier to use when coding this case?

Correct Modifier: -79

Reason: The procedure was unrelated to the original procedure; the unplanned nature of the event is irrelevant. A new postoperative period will be established.


Modifiers may be intimidating during your first several encounters. However, over time, you will become more comfortable with applying them and gain a more thorough understanding of when and how to use them.

Joy Woodke, COE, OCS, OCSR
• Coding and Practice Management Executive, American Academy of Ophthalmology, San Francisco
• Financial disclosure: None


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About Retina Today

Retina Today is a publication that delivers the latest research and clinical developments from areas such as medical retina, retinal surgery, vitreous, diabetes, retinal imaging, posterior segment oncology and ocular trauma. Each issue provides insight from well-respected specialists on cutting-edge therapies and surgical techniques that are currently in use and on the horizon.