Crystal's MCW Coder Hub🧬 ICD-10-CM H11.001 — Unspecified Pterygium of Right Eye
Quick Reference
Code: H11.001 | Billable: Yes | Chapter: 7 — Eye and Adnexa | HCC: No | Laterality: Right eye | Type: Unspecified (specific pterygium subtype not documented)
Description
ICD-10-CM H11.001 identifies a pterygium of the right eye where the specific subtype has not been documented by the treating provider. A pterygium (from the Greek pterygion, meaning “little wing”) is a fibrovascular growth of bulbar conjunctival tissue that encroaches onto the corneal surface — most commonly arising from the nasal limbus and extending across the cornea in a wing-shaped pattern.2 It is one of the most common ocular surface conditions encountered in ophthalmology and optometry practices, particularly among patients with high cumulative UV light exposure.2
H11.001 is assigned when the pterygium of the right eye is documented but the specific type or clinical subtype is not stated in the provider’s note — meaning the record does not describe the growth as central, double, amyloid, stationary peripheral, or progressive peripheral. When a specific type is documented, a more precise code from the H11.0 subcategory should always be selected. As a profee coder, review the full encounter note, slit lamp findings, and any procedural documentation before defaulting to the unspecified code — pterygium subtype is often determinable from the clinical description even when not explicitly labeled.3
Pterygium vs. Pseudopterygium — Critical Coding Distinction
Feature True Pterygium (H11.001) Pseudopterygium (H11.811) Origin Primary fibrovascular growth from bulbar conjunctiva crossing the limbus Secondary adhesion of conjunctiva to cornea following trauma, chemical burn, or inflammatory scarring Limbal attachment Present — pterygium has a true limbal attachment Absent — a probe can be passed beneath pseudopterygium at the limbus Progression Grows toward corneal center; may be stationary or progressive Does not grow in same manner; represents cicatricial adhesion UV association Strong association with chronic UV exposure No UV association — associated with prior ocular surface injury Recurrence Common after surgery (~30-80% without graft; ~5-15% with graft)14 Recurrence less typical; depends on underlying cause ICD-10-CM H11.00x-H11.06x H11.811-H11.819 Excludes1 relationship H11.0x Excludes1 H11.81- Mutually exclusive at code level These are Excludes1 to each other — a true pterygium and a pseudopterygium cannot be coded simultaneously for the same eye at the same encounter. The distinction is clinical and must be documented by the provider — a probe test at the limbus is the definitive bedside test.3
Code Structure & Hierarchy
Code Tree
- Chapter: 7 — Diseases of the Eye and Adnexa (H00-H59)
- Block: H10-H11 — Disorders of Conjunctiva
- H11 — Other disorders of conjunctiva ← this category
- H11.0 — Pterygium of eye ← this subcategory
- H11.00 — Unspecified pterygium of eye
- H11.01 — Amyloid pterygium
- H11.02 — Central pterygium of eye
- H11.03 — Double pterygium of eye
- H11.04 — Peripheral pterygium of eye, stationary
- H11.05 — Peripheral pterygium of eye, progressive
- H11.06 — Recurrent pterygium of eye
- H11.81 — Pseudopterygium of conjunctiva ← Excludes1 to all H11.0x
H11.001 vs. Sibling Codes — Type Specificity Decision Table
Code Assign When Provider Documents… H11.001 ”Pterygium, right eye” — no further type specified (NOS) H11.011 Amyloid pterygium, right eye — amyloid deposits within the fibrovascular tissue; confirmed histologically H11.021 Central pterygium, right eye — pterygium extends to or across the visual axis; threatens central vision H11.031 Double pterygium, right eye — two pterygia present on the same eye (nasal AND temporal) H11.041 Peripheral, stationary — documented as not progressing; stable on serial measurements H11.051 Peripheral, progressive — documented as actively growing; advancing toward visual axis H11.061 Recurrent pterygium, right eye — regrowth after prior surgical excision — this is one of the most clinically and surgically significant subtypes; requires the most aggressive surgical management2 H11.811 Pseudopterygium — secondary conjunctival adhesion to cornea following injury; probe passes under limbal attachment; Excludes1 to H11.0013 Before defaulting to H11.001, review the chart for any of these descriptors. A clinical note documenting “growing pterygium” or “advancing pterygium” supports H11.051 (progressive); a note documenting “history of prior pterygium excision” with regrowth supports H11.061 (recurrent).
Instructional Notes
Excludes1 — Mutually Exclusive
Cannot be coded together with H11.001 at the same encounter for the same eye:
- Pseudopterygium of conjunctiva, right eye (H11.811) — a structurally and etiologically distinct entity representing secondary cicatricial adhesion following ocular surface trauma, chemical injury, or inflammation; mutually exclusive with true pterygium coding at the H11.0 level13
Also Excludes1 at the H11 Category Level
The following condition is Excludes1 at the broader H11 category level — not specific to pterygium but relevant to anterior segment coding in the same patient:
- Keratoconjunctivitis (H16.2-) — inflammatory condition of cornea and conjunctiva; classified separately and cannot be coded simultaneously as the same diagnosis expression1
No Excludes2 at H11.001 Level
There are no Excludes2 notes specific to H11.001. However, the following conditions may coexist and should be coded additionally when separately documented and confirmed:
- Dry eye disease / keratoconjunctivitis sicca, right eye (H04.121) — pterygium commonly co-occurs with ocular surface dryness and disruption of the tear film; both conditions are separately reportable and should each be addressed in the treatment plan when present2
- Corneal pannus or superficial corneal opacity associated with advanced pterygium — evaluate whether H18.891 (other specified corneal disorders) applies when significant corneal involvement is documented
- Symptomatic pterygium in the context of corneal astigmatism — corneal topography changes may be documented but do not alter the H11 code selection
Use Additional Code
When pterygium is related to a documented occupational or environmental exposure:
- Consider Z77.098 (Contact with and (suspected) exposure to other hazardous, chiefly nonmedicinal, chemicals) or the appropriate Z57.5 (Occupational exposure to toxic agents in other industries) when the provider explicitly links occupational outdoor UV exposure to the pterygium development
- H04.121-H04.123 — Dry eye syndrome; code additionally when documented as a concurrent or contributing condition
Clinical Description
A pterygium is a benign but potentially vision-threatening fibrovascular proliferation of bulbar conjunctival tissue that crosses the corneal limbus and grows progressively onto the corneal surface.2 Histologically, the lesion consists of degenerated subepithelial connective tissue with fibrovascular proliferation, elastotic degeneration of collagen, and a surface layer of conjunctival epithelium — it is not a true neoplasm but represents an elastotic degenerative process driven primarily by chronic UV-B exposure and oxidative stress.2 The condition is strongly associated with residence near the equator, outdoor occupational or recreational UV exposure, and is among the most commonly encountered anterior segment conditions in general ophthalmology and optometry settings.
Pathophysiology:
- Chronic UV-B radiation → oxidative damage to limbal stem cells → abnormal conjunctival epithelial proliferation and subconjunctival fibrovascular invasion of the corneal stroma2
- Disruption of the Bowman’s layer of the cornea at the advancing head of the pterygium
- Associated with matrix metalloproteinase (MMP) upregulation driving fibrovascular invasion
- Limbal stem cell dysfunction is a key contributing mechanism, explaining the origin of the growth at the limbus and why recurrence is so common after excision
Clinical Presentation:
- Most commonly arises from the nasal limbus in a triangular or wing-shaped growth toward the central cornea, though temporal origin does occur
- Appearance: raised, fleshy, pink-red vascularized fibrovascular lesion with a distinct “head” (advancing corneal portion) and “body” (conjunctival portion)
- Cap (Fuchs’ flecks): iron line (Stocker’s line) may be seen at the advancing head on slit lamp — a classic finding
- Symptoms include redness, irritation, foreign body sensation, tearing, and induced corneal astigmatism — larger pterygia cause significant irregular astigmatism that can reduce corrected visual acuity14
- Visual axis involvement (central pterygium — H11.021) is an indication for surgery regardless of patient symptoms
- Serial corneal topography is essential to monitor progression and detect induced astigmatism before visual acuity is affected
Pterygium Subtypes (All Unspecified When Not Documented → H11.001):
| Subtype | Clinical Feature | Surgical Urgency |
|---|---|---|
| Peripheral stationary | Not advancing; stable on serial topography | Monitor; surgery if symptomatic |
| Peripheral progressive | Actively growing; advancing on serial topography | Surgical excision recommended to prevent visual axis involvement |
| Central | Has reached or crossed the visual axis | Surgical — threatens visual function |
| Double | Nasal AND temporal pterygium, same eye | Surgical complexity increased; may require two separate excisions |
| Amyloid | Amyloid deposits confirmed histopathologically | Surgical; histology-driven subtype |
| Recurrent | Regrowth after prior excision | Most aggressive subtype; higher surgical difficulty; conjunctival autograft or amniotic membrane preferred14 |
Coding Guidelines
Official Guideline Reference
ICD-10-CM Official Guidelines FY2026, Section I.C.7 — Diseases of the Eye and Adnexa
- Assign H11.001 when the provider documents pterygium of the right eye without specifying the clinical subtype. If the provider note, slit lamp findings, or surgical documentation describes the pterygium as progressive, stationary, central, double, amyloid, or recurrent, use the appropriate subtype-specific code from H11.01x-H11.06x.3
- H11.001 and H11.811 (pseudopterygium) are mutually exclusive (Excludes1) — the clinical and probe test distinctions between these two entities must be documented before code assignment. Do not assume; query when the record is ambiguous.3
- When pterygium is the primary reason for a pre-operative or surgical visit, H11.001 is the first-listed/principal diagnosis. When identified as an incidental finding during a visit for another primary condition, it is coded as an additional diagnosis if examined and documented in the assessment.
- H11.061 (recurrent pterygium, right eye) should be assigned — not H11.001 — when the provider documents history of prior pterygium excision AND the pterygium has regrown. Review the surgical history and PMH carefully before defaulting to the unspecified code.
Sequencing Tips
- Outpatient — First-listed diagnosis: H11.001 when pterygium is the primary reason for the encounter (new diagnosis, pre-operative evaluation, monitoring visit)
- Pre-operative visits: H11.001 (or appropriate specific subtype) is the first-listed diagnosis for pre-op evaluations and the surgical encounter itself
- Incidental finding: Code as an additional diagnosis when documented and addressed alongside another primary ocular condition
- POA (inpatient): Virtually always Y — pterygium is a chronic, slowly progressive condition. POA = N is essentially never applicable; inpatient admission solely for pterygium excision is extremely rare and typically occurs only for complex recurrent cases or cases combined with other ocular procedures
- Recurrence: After surgical excision, if regrowth occurs at any subsequent encounter, retire H11.001 and assign H11.061 (recurrent pterygium, right eye) — one of the most commonly missed coding upgrade opportunities in anterior segment practices
HCC Mapping
HCC Risk Adjustment
HCC Relevant: No HCC Model: CMS-HCC v28 — fully operative CY2026 HCC Category: Not mapped HCC Coefficient: 0.000 Risk Adjustment Impact: None
H11.001 carries no HCC weight under CMS-HCC v28.67 Pterygium is classified as a benign, non-systemic, anterior segment condition and does not meet the clinical severity threshold for HCC mapping under any version of the CMS-HCC model. No associated etiology or secondary codes commonly accompanying pterygium carry HCC weight either.
Associated HCC Opportunities
While H11.001 and its sibling codes carry no HCC weight, verify and capture the following if documented in pterygium patients:
- Type 2 diabetes with ophthalmic complications — if a diabetic patient has pterygium as a coexisting anterior segment finding, ensure all diabetic retinopathy codes (E11.3x-) are captured separately — they carry HCC 122 weight under V287
- Glaucoma — pterygium commonly coexists with glaucoma (both UV-associated in certain populations); glaucoma codes (H40.x-) carry HCC weight under V28 depending on severity and type
- AMD — if coexisting, capture appropriately with relevant HCC weight per V28 mapping
MS-DRG Mapping
DRG Assignment
MS-DRG Description MDC GMLOS 124 Other Disorders of the Eye with MCC MDC 2 4.6 125 Other Disorders of the Eye with CC MDC 2 3.1 126 Other Disorders of the Eye without CC/MCC MDC 2 2.2
CC/MCC Status & Inpatient Context
- CC status: No
- MCC status: No
- HAC designation: No
- POA exempt: No
- Inpatient note: Inpatient admission for pterygium excision alone is extremely rare — pterygium surgery (65420 or 65426) is almost universally performed in an outpatient ambulatory surgery center (ASC) or office-based setting. In the uncommon scenario where pterygium excision is combined with another inpatient ocular procedure (e.g., concurrent cataract surgery with other comorbidities requiring admission), H11.001 will appear as a secondary diagnosis. As the sole diagnosis, H11.001 would group to MS-DRG 126 in the absence of CC/MCC diagnoses.4 For inpatient facility coding, when a qualifying ICD-10-PCS surgical procedure is performed (excision of right conjunctiva — 08B23ZZ), the case may group to a surgical MS-DRG within MDC 02.
CPT Crosswalk
| CPT | Description | wRVU (approx.) | Global Period | Asst. Payable (Medicare) |
|---|---|---|---|---|
| 92004 | Ophthalmological exam, new patient, comprehensive, with dilation | 2.67 | 0 days | N/A — E/M |
| 92014 | Ophthalmological exam, established patient, comprehensive, with dilation | 1.34 | 0 days | N/A — E/M |
| 92025 | Computerized corneal topography, unilateral or bilateral, with interpretation and report | 0.00 (TC/PC split) | 0 days | N/A — Diagnostic |
| 92250 | Fundus photography with interpretation and report | 0.00 (TC/PC split) | 0 days | N/A — Diagnostic |
| 65430 | Scraping of cornea, diagnostic, for smear and/or culture | 0.85 | 0 days | N/A — Diagnostic |
| 65420 | Excision or transposition of pterygium; without graft | ~3.00 | 90 days | ⚠️ Verify MPFS indicator |
| 65426 | Excision or transposition of pterygium; with graft | ~5.47 | 90 days | ⚠️ Verify MPFS indicator |
| 68100 | Biopsy of conjunctiva | ~1.00 | 0 days | N/A — Diagnostic |
The choice between these two codes is the single most important CPT decision in pterygium surgical coding and is one of the most audited code pairs in anterior segment surgery.910
Code Procedure When to Assign Recurrence Risk 65420 Excision or transposition of pterygium — without graft Bare sclera technique; simple avulsion — no conjunctival or amniotic membrane graft placed High recurrence (~30-80%) — primarily used for small, low-risk pterygia 65426 Excision or transposition of pterygium — with graft Conjunctival autograft (CAU) or amniotic membrane transplant (AMT) is placed following excision Lower recurrence (~5-15%) — current standard of care for most surgical pterygium cases14
- The operative note must document the graft placement to support 65426 — if the note describes simple excision without graft, 65420 is the correct code regardless of intent
- Mitomycin C (MMC) application alone does NOT constitute a graft — MMC applied to the scleral bed post-excision does not upgrade 65420 to 65426
- When a conjunctival autograft is harvested and sutured/glued in place, 65426 is supported — document the harvest site, graft dimensions, and fixation method (suture vs. fibrin glue) explicitly in the operative note
- Amniotic membrane graft (fresh or processed — e.g., Prokera, AmnioGraft) also supports 65426 — document the product name and lot number14
NCCI Bundling — Pterygium CPT Codes
Per the CMS 2026 NCCI Medicare Coding Policy Manual:11
- CPT 65420 and 65426 describe excision of pterygium without and with graft, respectively — these two codes are mutually exclusive (NCCI edit with modifier indicator 0) and should never be billed together for the same eye on the same date
- Graft codes and ocular surface reconstruction codes must be carefully reviewed against current NCCI edit pairs before billing any additional conjunctival graft CPT alongside 65426 — bundling applies to ancillary graft harvesting CPT codes when performed as part of the same pterygium procedure
Modifier -RT Required on Surgical Claims
Append modifier -RT (right side) to 65420 or 65426 for all right eye pterygium excision claims. Medicare and most commercial payers require the laterality modifier on all surgical CPT codes for unilateral eye procedures. Failure to append -RT may result in claim rejection or denial when the same CPT code was recently billed for the left eye.3
ICD-10-PCS Crosswalk
PCS Applicability
ICD-10-PCS applies in the inpatient setting only. Pterygium excision in the inpatient setting is exceedingly rare; however, if performed, the PCS codes below apply. The body part coded in ICD-10-PCS for pterygium excision is the conjunctiva (the tissue being excised), not the cornea — even though the pterygium also involves the corneal surface, the origin and primary tissue of the pterygium is conjunctival.
| PCS Code | Root Operation | Body Part | Approach | Device | Qualifier |
|---|---|---|---|---|---|
| 08B23ZZ | Excision | Conjunctiva, Right | Percutaneous | No Device | No Qualifier |
| 08T23ZZ | Resection | Conjunctiva, Right | Percutaneous | No Device | No Qualifier |
| 08R2X73 | Replacement | Conjunctiva, Right | External | Autologous Tissue Substitute | No Qualifier |
Character breakdown — excision of right conjunctiva (08B23ZZ):
- Section: 0 — Medical and Surgical
- Body System: 8 — Eye
- Root Operation: B — Excision
- Body Part: 2 — Conjunctiva, Right
- Approach: 3 — Percutaneous
- Device: Z — No Device
- Qualifier: Z — No Qualifier
PCS Root Operation Distinction
- Excision (08B23ZZ) — used when only a portion of the conjunctiva is removed (the pterygium tissue itself); this is the typical root operation for pterygium excision
- Resection (08T23ZZ) — used when the entire conjunctiva of the right eye is removed; not typical for pterygium surgery alone
- Replacement (08R2X73) — applicable when a conjunctival autograft is harvested and placed; the “Autologous Tissue Substitute” device character (7) captures the graft component in PCS
ICD-10-CM Crosswalk
| Code | Description | Relationship |
|---|---|---|
| H11.002 | Unspecified pterygium, left eye | Contralateral equivalent |
| H11.003 | Unspecified pterygium, bilateral | Bilateral equivalent — use when both eyes affected |
| H11.009 | Unspecified pterygium, unspecified eye | Less specific — avoid if laterality documented |
| H11.011 | Amyloid pterygium, right eye | Use when amyloid deposits confirmed histologically |
| H11.021 | Central pterygium, right eye | Use when visual axis is threatened or involved |
| H11.031 | Double pterygium, right eye | Use when nasal AND temporal pterygium present |
| H11.041 | Peripheral pterygium, stationary, right eye | Use when documented as stable/non-progressing |
| H11.051 | Peripheral pterygium, progressive, right eye | Use when documented as actively advancing |
| H11.061 | Recurrent pterygium, right eye | Use after prior excision with regrowth — do not use H11.001 for recurrence |
| H11.811 | Pseudopterygium of conjunctiva, right eye | Excludes1 — secondary cicatricial adhesion; not a true pterygium |
| H18.891 | Other specified disorders of cornea, right eye | Use for associated corneal pannus or scarring from advanced pterygium |
| H04.121 | Dry eye syndrome, right eye | May coexist — separately reportable |
| H16.211 | Exposure keratoconjunctivitis, right eye | May coexist in advanced cases with significant corneal surface disruption |
| Z77.098 | Contact with/exposure to other hazardous nonmedicinal chemicals | Use for documented UV exposure history relevant to pterygium etiology |
Coding Examples
Example 1 — Outpatient New Patient Visit, Right Eye Pterygium, No Surgery
Scenario: A 52-year-old outdoor construction worker presents as a new patient to an ophthalmologist with a visible growth on the right eye causing redness and irritation. Slit lamp exam reveals a pink fleshy fibrovascular growth arising from the nasal limbus of the right eye, not yet approaching the visual axis. The provider documents “pterygium, right eye” — no further subtype specified. Artificial tear lubrication is recommended. Surgery deferred.
First-listed Dx: H11.001 — Unspecified pterygium of right eye CPT: 92004--RT — Comprehensive ophthalmological exam, new patient, with dilation Notes: No surgical or diagnostic procedure codes beyond the E/M; topography is appropriate if ordered but was not performed at this visit. No subtype documented — H11.001 is correct. If the provider had noted “advancing toward visual axis” or “growing on topography,” H11.051 would be more appropriate.
Example 2 — Established Patient, Pre-operative Evaluation, Right Eye Pterygium, Progressive
Scenario: A 58-year-old established patient with serial topography documenting progressive pterygium growth toward the visual axis. Provider documents “progressive peripheral pterygium, right eye — surgical excision with conjunctival autograft recommended.”
First-listed Dx: H11.051 — Peripheral pterygium, progressive, right eye (more specific than H11.001 — type is documented) CPT: 92014-RT — Comprehensive ophthalmological exam, established patient; 92025-RT — Corneal topography with interpretation Notes: H11.001 would be incorrect here — the provider has documented the progressive type, requiring the more specific code. This is a prime example of when H11.001 should be retired in favor of a subtype code.
Example 3 — Surgical Case, Pterygium Excision with Conjunctival Autograft, Right Eye
Scenario: A 45-year-old patient undergoes pterygium excision of the right eye. The operative note documents: “Excision of pterygium, right eye. Conjunctival autograft harvested from superior bulbar conjunctiva and secured to scleral bed with fibrin glue (Tisseel). Dimensions: 8 x 5 mm. Pterygium NOS — no specific subtype documented in the pre-op note.”
CPT: 65426-RT — Excision or transposition of pterygium, with graft, right eye ICD-10-CM: H11.001 — Unspecified pterygium of right eye Notes: 65426 is correct — the operative note explicitly documents conjunctival autograft placement with fibrin glue fixation. 65420 would be an undercoding error here. The graft harvest site, dimensions, and fixation method are all documented — these are the key elements needed to support 65426 under audit.1011
Example 4 — Recurrent Pterygium, Right Eye — Post-Excision Regrowth
Scenario: An established patient who had pterygium excision 14 months ago returns with documented regrowth of fibrovascular tissue at the nasal limbus of the right eye. The provider documents “recurrent pterygium, right eye — previously excised; now regrowing nasally.”
First-listed Dx: H11.061 — Recurrent pterygium of right eye (do NOT use H11.001) CPT (if re-excision performed): 65426-RT — Excision with graft (conjunctival autograft strongly preferred for recurrent cases; amniotic membrane or mucous membrane graft also appropriate) Notes: H11.001 is incorrect for recurrent cases — H11.061 is required once prior excision is documented and regrowth has occurred. Recurrent pterygium has distinct surgical considerations and higher recurrence risk with bare sclera technique; 65426 is almost universally appropriate for recurrent cases.14
Example 5 — Bilateral Pterygium, Both Eyes Unspecified Type
Scenario: A 61-year-old patient presents with pterygium affecting both eyes. Provider documents “bilateral pterygium — right eye more advanced than left; type not specified for either eye.”
First-listed Dx: H11.003 — Unspecified pterygium, bilateral (use bilateral code — do NOT code H11.001 + H11.002 separately when bilateral code exists and bilateral involvement is confirmed) Notes: Per ICD-10-CM convention, H11.003 is required when bilateral involvement is documented and types are both unspecified. If only the right eye is being treated surgically at this encounter, append -RT to the CPT code — the bilateral ICD-10-CM code remains appropriate as it reflects the patient’s total diagnosis picture regardless of which eye is being treated today.3
Coding Pitfalls & Tips
Common Errors
- Using H11.001 for recurrent pterygium — once a prior excision is documented and regrowth has occurred, H11.061 is required; H11.001 is a persistent, common error in practices with long-term pterygium patients
- Confusing pterygium and pseudopterygium — H11.001 and H11.811 are Excludes1 to each other; assigning both for the same eye at the same encounter is a coding violation; the probe test finding and clinical history should drive the distinction3
- Billing 65420 when a graft was placed — if the operative note documents conjunctival autograft or amniotic membrane graft, 65426 must be billed; undercoding 65420 on a grafted case is both a lost revenue opportunity and inaccurate claim submission
- Forgetting modifier RT on surgical claims for right-eye procedures — laterality modifiers are required by Medicare and most commercial payers for all unilateral eye surgery CPT codes; omission causes claim denials and same-code bilateral billing flag alerts
- Coding H11.009 (unspecified eye) when right eye laterality is clearly documented — always assign H11.001 when the right eye is documented anywhere in the record
- Coding H11.001 + H11.002 simultaneously instead of H11.003 for bilateral pterygium — the bilateral code takes precedence per ICD-10-CM convention when both eyes are affected by the same unspecified type3
- Applying MMC and billing 65426 — Mitomycin C chemoadjuvant does NOT constitute a graft. 65420 applies when no graft is placed regardless of adjuvant use
Pro Tips
- Document the subtype — ophthalmologists and optometrists often dictate “pterygium” without specifying stationary vs. progressive; as a profee coder, review the slit lamp documentation and serial topography results in the chart — phrases like “encroaching on the visual axis,” “advancing,” “stable on topography,” or “previously resected” are clinical specificity signals that directly upgrade the ICD-10 code from H11.001 to a more specific sibling
- Serial topography documentation is particularly valuable for distinguishing H11.041 (stationary) from H11.051 (progressive) — if topography maps are in the record showing corneal curvature changes over time, that data supports the progressive designation without needing the provider to explicitly use the word “progressive”
- Corneal astigmatism induced by pterygium is not separately coded as an additional ICD-10 code in most cases — the pterygium code captures the full clinical picture; document the degree of induced astigmatism in the note for medical necessity purposes but do not add a separate astigmatism ICD-10 code unless the astigmatism is being separately treated
- The 90-day global period for 65420 and 65426 means all related follow-up care, suture removal, topography checks, and routine post-op visits are bundled — only separately identifiable, unrelated services during the global window require modifier -24 for the E/M
CDI Query Opportunities
CDI Flags
- Subtype documentation: What is the clinical type of this pterygium — stationary peripheral, progressive peripheral, central, double, or amyloid? Query the provider for explicit subtype documentation to retire H11.001 in favor of a more specific code at the next encounter
- Recurrence history: Is there a prior history of pterygium excision on this eye? If so, and regrowth is present, H11.061 is required — query if surgical history is in the chart but the note does not explicitly use the word “recurrent”
- True pterygium vs. pseudopterygium: Has a probe test been performed to assess limbal attachment? If documentation is ambiguous, query the provider to confirm whether this is a primary fibrovascular pterygium (H11.0x) or a secondary cicatricial adhesion (H11.811)
- Bilateral involvement: Is the fellow eye also affected? Pterygium is bilateral in a meaningful percentage of outdoor workers — query for examination and documentation of the left eye at each encounter, and update to H11.003 if bilateral involvement is confirmed
- Graft type: For surgical cases — what graft type was used? Conjunctival autograft? Amniotic membrane? This distinction drives 65420 vs. 65426 and must be explicitly documented in the operative note
- Associated dry eye: Is concurrent dry eye disease (H04.121) documented and being treated? Pterygium and dry eye frequently coexist — document and code both to capture the full clinical picture and support medical necessity for lubricant prescriptions
Related Codes
- Laterality family: H11.002, H11.003, H11.009
- Specific pterygium subtypes, right eye: H11.011, H11.021, H11.031, H11.041, H11.051, H11.061
- Pseudopterygium (Excludes1): H11.811, H11.812, H11.813
- Associated corneal findings: H18.891
- Associated anterior segment conditions: H04.121, H16.211
- CPT crosswalk: 65420, 65426, 92014, 92004, 92025, 92250, 68100
- PCS crosswalk: 08B23ZZ, 08T23ZZ, 08R2X73
- AAPC Codify — ICD-10-CM H11.001 & H11.0 Excludes1 Notes, aapc.com
- Unbound Medicine — H11.001 Unspecified Pterygium of Right Eye, unboundmedicine.com
- CMS — ICD-10-CM Official Guidelines for Coding and Reporting FY2026, cms.gov
- CMS — ICD-10-CM/PCS MS-DRG v37.2 Definitions Manual, cms.gov
- FindACode — ICD-10-CM H11.001, findacode.com
- MedPAC — MA Part D CY2027 Comment Letter, medpac.gov (2026)
- BCA — HCC Updates: Capturing Risk Accurately in 2026, bcarev.com (2026)
- Wolters Kluwer — How CMS-HCC Version 28 Will Impact RAF Scores, wolterskluwer.com
- AAPC — CPT Code 65426 Excision Procedures on the Cornea, aapc.com
- AAPC — CPT Code 65420 Excision Procedures on the Cornea, aapc.com
- CMS — 2026 NCCI Medicare Coding Policy Manual, cms.gov
- Review of Ophthalmology — Coding and Reimbursement: 2026 Update, reviewofophthalmology.com (2026)
- GenHealth.ai — ICD-10-CM H11.0 Pterygium of Eye, genhealth.ai
- MD Clarity — CPT Code 65426: What It Is, Modifiers, Reimbursement, mdclarity.com
- AAPC — ICD-10-CM H11.81 Pseudopterygium of Conjunctiva, aapc.com
- CMS — ICD-10-CM/PCS MS-DRG v33.0 Definitions Manual (Pterygium DRG reference), cms.gov