ICD-10 Coding for Red Eye in Ophthalmology
The most appropriate ICD-10 code for a red eye depends on the underlying diagnosis, but for unspecified conjunctivitis (the most common cause of red eye), use H10.9 (unspecified conjunctivitis), with laterality specified as H10.91 (right eye), H10.92 (left eye), or H10.93 (bilateral). 1
Primary Coding Approach
The ICD-10 coding for red eye requires identifying the specific etiology rather than coding "red eye" as a symptom alone. The American Academy of Ophthalmology guidelines emphasize that conjunctivitis encompasses diverse conditions requiring specific diagnostic classification. 1
Most Common ICD-10 Codes for Red Eye Presentations:
Conjunctivitis (Most Common):
- H10.9 - Unspecified conjunctivitis (when etiology unclear) 1
- H10.91 - Unspecified conjunctivitis, right eye 1
- H10.92 - Unspecified conjunctivitis, left eye 1
- H10.93 - Unspecified conjunctivitis, bilateral 1
Specific Conjunctivitis Types:
- B30.x - Viral conjunctivitis (when viral etiology confirmed) 1
- H10.0x - Mucopurulent conjunctivitis (bacterial) 1
- H10.1x - Acute atopic conjunctivitis (allergic) 1
Critical Coding Considerations
Laterality is mandatory in ICD-10 coding. The final digit always specifies: 1 = right eye, 2 = left eye, 3 = bilateral. 1 If bilateral presentation exists and no bilateral code is available, assign separate codes for both right and left eyes. 1
When Red Eye Represents More Serious Conditions:
Glaucoma-Related:
Other Serious Etiologies Requiring Different Codes:
- Acute angle-closure glaucoma requires H40.2x series 2, 3
- Anterior uveitis requires H20.x series 2, 3
- Corneal pathology requires H16.x-H18.x series 2, 3
- Herpes simplex keratitis requires B00.52 2, 3
Documentation Requirements for Accurate Coding
To code appropriately, documentation must specify: 1
- Laterality (right, left, or bilateral)
- Etiology (viral, bacterial, allergic, or unspecified)
- Acuity (acute, chronic, or recurrent)
- Associated findings (discharge character, pain, vision changes)
Common pitfall: Using symptom codes (like R68.13 for "apparent life threatening event") instead of diagnosis codes leads to claim denials. 1 Always code the underlying condition causing the red eye, not the symptom itself.
Special Populations
Pediatric patients may require additional codes for associated systemic conditions when red eye is secondary to atopic dermatitis or other systemic disease. 1
Contact lens wearers with red eye should be coded for the specific complication (e.g., contact lens-related keratitis H16.2x) rather than simple conjunctivitis. 2, 4