H16.329 is the ICD-10-CM diagnosis code for diffuse interstitial keratitis, unspecified eye. This code describes inflammation of the cornea (the clear front part of the eye) that is spread throughout its layers, but the specific eye affected is not documented. This condition causes corneal clouding and can affect vision. H16.329 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering disorders of sclera, cornea, iris and ciliary body (h15-h22).

H16.329 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

Always attempt to determine which eye is affected (right, left, or bilateral) and use the appropriate 7th character code (1 for right eye, 2 for left eye, 3 for bilateral) rather than defaulting to unspecified (9).