Age-related macular degeneration (AMD) is among the most common retinal diagnoses. Although the clinical features of the disease are well known, ICD-10 coding can be confusing if details such as stage, activity, and laterality are not clearly documented. Incomplete documentation may prompt questions about the medical necessity of diagnostic tests or intravitreal injections. This Q&A addresses common sources of confusion and offers practical guidance to support clear, accurate documentation.
Q: What is the difference between exudative (also called neovascular or wet) AMD and dry AMD?
A: In simple terms, exudative AMD is caused by abnormal, leaky blood vessels that can rapidly damage central vision, while dry AMD is associated with drusen accumulation and progressive retinal atrophy, leading to gradual vision loss.
Q: What are the stages and severity of exudative AMD?
A: Exudative AMD has 2 stages:
- Active, with leaking vessels, or
- Inactive, with stable, fibrotic, or scarred vessels
Disease severity is usually classified as mild, moderate, or severe. Chart documentation should include supportive details, not just the diagnosis code, to substantiate disease activity and severity.
Q: What are the ICD-10 codes for wet AMD?
A: The ICD-10 codes listed below are incomplete because they require a 7th character to reach the highest specificity:
- H35.321 - Exudative age-related macular degeneration, right eye
- H35.322 - Exudative age-related macular degeneration, left eye
- H35.323 - Exudative age-related macular degeneration, bilateral
Q: What is the 7th character for wet AMD, and why is it needed?
A: The seventh character specifies disease activity or stage. ICD-10 diagnosis codes should be documented and reported to the highest level of specificity supported by the clinical record. The seventh-character options include:
- 0 - stage unspecified
- 1 - with active choroidal neovascularization
- 2 - with inactive choroidal neovascularization OR with involuted or regressed neovascularization
- 3 - with inactive scar
Q: What are the stages of dry AMD?
A: Dry AMD is generally classified into 3 stages:
- Early: characterized by small drusen and minimal pigment changes, with no vision loss or only mild changes.
- Intermediate: marked by medium to large soft drusen, more noticeable changes in retinal pigment, and no to mild vision loss.
- Advanced: distinguished by geographic atrophy with substantial retinal pigment epithelium and photoreceptor loss, with or without subfoveal involvement. Subfoveal involvement refers to disease affecting the area directly beneath the fovea—the central pit of the macula responsible for sharp central vision used for tasks such as reading, driving, and facial recognition.
As with wet AMD, the chart documentation should include supporting clinical information, not just the diagnosis code.
Q: What are the ICD-10 codes for dry AMD?
A: As with wet AMD, the ICD-10 codes listed below are incomplete because they require a 7th character to reach the highest specificity:
- H35.311 - Nonexudative age-related macular degeneration, right eye
- H35.312 - Nonexudative age-related macular degeneration, left eye
- H35.313 - Nonexudative age-related macular degeneration, bilateral
Q: What is the 7th character for dry AMD?
A: As with wet AMD, the 7th character indicates the stage of the disease.
- 0 - stage unspecified
- 1 - early dry stage
- 2 - intermediate dry stage
- 3 - advanced atrophic without subfoveal involvement, or advanced dry stage
- 4 - advanced atrophic with subfoveal involvement
Q: Where do most coding issues occur with wet and dry AMD?
A: Many errors arise because the diagnosis codes for both conditions begin with H35.3. The laterality and stage digits—the sixth and seventh characters—are structured similarly for wet and dry AMD. The key distinction is the fifth character: 1 designates nonexudative (dry) AMD, and 2 designates exudative (wet) AMD, followed by laterality and then disease stage.
Careful attention to these details is essential when coding AMD. Transposing digits or misidentifying wet vs dry disease can result in inaccurate claims, delayed reimbursement, or questions about medical necessity for diagnostic testing and treatment. Consistent, detailed clinical documentation—clearly specifying disease type, laterality, and stage—helps ensure coding accuracy, supports appropriate reimbursement, and reduces the risk of audits or denials. RP
