S01.109AUnspecified open wound of unspecified eyelid and periocular area, initial encounter

S01.109A is the ICD-10-CM diagnosis code for unspecified open wound of unspecified eyelid and periocular area, initial encounter. It belongs to category S01 (open wound of head), block S00-S09 (injuries to the head) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

The 7th character "A" means initial encounter: use it while the patient is receiving active treatment for the condition.

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 124 (Other Disorders of the Eye with MCC or Thrombolytic Agent, relative weight 1.2471), DRG 125 (Other Disorders of the Eye without MCC, relative weight 0.7702), DRG 963 (Other Multiple Significant Trauma with MCC, relative weight 2.6363), DRG 964 (Other Multiple Significant Trauma with CC, relative weight 1.4972) and DRG 965 (Other Multiple Significant Trauma without CC/MCC, relative weight 1.0059), in MDC 02 (Diseases and Disorders of the Eye) and MDC 24 (Multiple Significant Trauma), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It is an unspecified code for which a more specific option (often laterality) exists, and the Medicare Code Editor flags it for review on inpatient claims.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 870.9 (unspecified open wound of ocular adnexa).