Medical Coding for Glaucoma Under ICD-10-CM – Key Considerations

by | Last updated Jun 14, 2023 | Published on Jul 22, 2016 | Medical Coding

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A common eye condition that can cause permanent blindness, glaucoma is estimated to affect over 3 million Americans. According to the Center for Disease Control and Prevention/National Center for Health Statistics, the condition accounts for over 10 million visits to physicians each year. Coding for glaucoma has undergone significant changes in recent years, with some affecting reimbursements. Professional medical coding services can help physicians deal with the complexity of the glaucoma surgical code family and receive appropriate payment.

ICD-10 coding for glaucoma requires in-depth knowledge about the condition. An experienced medical coding company can ensure accuracy in ICD-10 code selection for glaucoma. ICD-10, coding for conditions related to the eye has become much more complex and requires those who perform ophthalmology medical coding to have an thorough understanding of anatomical structure and pathophysiology.

The second leading cause of blindness, glaucoma occurs due to damage to the optic nerve and is usually linked to build up of pressure in the eye. High eye pressure is the result of the collection of a fluid (aqueous humor) that continuously flows in and out of the eye.

There are two types of glaucoma – ‘open angle’ and ‘angle closure’. In the former, the fluid passes too slowly through the drain, builds up, and damages the optic nerve. Low-tension or normal-tension glaucoma is open angle glaucoma that occurs due to injury or infection, without rise in eye pressure.

Angle closure occurs when the iris bulges and blocks the drainage angle, preventing the fluid from circulating through the eye and causing pressure to increase.

In ICD-10, coding for glaucoma includes two elements: laterality and the stage of the condition. Unlike ICD-9-CM, ICD-10-CM specifies left, right, and bilateral. In order to properly report glaucoma with the right the ICD-10-CM code, physicians must document whether condition has affected the right or left eye or both. So in the ICD-10 diagnosis codes for glaucoma are

H40 Glaucoma – not a specified code as there are others underneath it that describe the diagnosis in detail such as

  • H40.0 Glaucoma suspect
  • H40.00 Preglaucoma, unspecified
  • H40.001 – right eye
  • H40.002 – left eye
  • H40.003 – bilateral
  • H40.009 – unspecified eye

Stages of the eye condition are categorized as: unspecified, mild, moderate, severe, and indeterminate. Such staging help physicians manage the condition better through careful assessment and documentation of clinical damage. Understanding disease stage is crucial for both clinical and research purposes. Accurate ophthalmology coding accompanied by proper physician documentation makes this possible. If the stage cannot be determined, an unspecified code should be used for lack of documentation.

The American Academy of Ophthalmology reports that, in 2016, Medicare fee cuts are much higher than the Relative Value Scale Update Committee (RUC) recommendations. Several glaucoma procedures are facing cuts of up to 19 percent in 2016. This is all the more reason why professional medical billing and coding services are crucial for ophthalmologists to maximize reimbursement.


Rajeev Rajagopal

Rajeev Rajagopal, the President of OSI, has a wealth of experience as a healthcare business consultant in the United States. He has a keen understanding of current medical billing and coding standards.

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