H51.20 is the ICD-10-CM diagnosis code for internuclear ophthalmoplegia, unspecified eye. Internuclear ophthalmoplegia is a condition where the eye muscles don't work together properly due to a problem with the nerve connections in the brain, causing difficulty with coordinated eye movements. This code is used when the specific eye affected is not documented. H51.20 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering disorders of ocular muscles, binocular movement, accommodation and refraction (h49-h52).

H51.20 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.

If documentation specifies which eye is affected (right or left), use the more specific codes H51.21 or H51.22 instead of the unspecified code H51.20.