Ophthalmology and Optometry Coding Alert

Question: Can 375.15 and 370.21 be used interchangeably? When would one be the preferred diagnosis code as opposed to the other?

Kansas Subscriber

Answer: Both 375.15 and 370.21 are diagnosis codes relating to the cornea, so a detailed description of the patient's confirmed symptoms from the physician is crucial for the selection of the proper code.

ICD-9-CM code 375.15 (Tear film insufficiency, unspecified) is defined in the ICD-9-CM manual as "eye dryness and irritation due to insufficient tear production," which may present in the form of dry-eye syndrome. When identifying diagnoses that require 375.15, look for descriptions that indicate the patient does not yet have an identifiable condition of the cornea, e.g., corneal lesions, because this code should be used only when the patient's cornea is unaffected. Use 375.15 when a patient presents with punctate keratitis and the physician indicates that it is a result of dry-eye syndrome.

Use 370.21, on the other hand, when a patient presents with punctate keratitis that is not an indicated result of dry-eye syndrome. ICD-9-CM guidelines define 370.21 as "formation of cellular and fibrinous deposits on posterior surface" that may develop after injury or iridocyclitis. These codes should not be used interchangeably if you are unsure of which code to choose, get more information from the physician before deciding.