{"code":"H49.13","type":"code","title":"Fourth [trochlear] nerve palsy, bilateral","codeAlso":[],"includes":[],"modern_v":"official26","codeFirst":[],"excludes1":[],"excludes2":["internal ophthalmoplegia (H52.51-)","internuclear ophthalmoplegia (H51.2-)","progressive supranuclear ophthalmoplegia (G23.1)","nystagmus and other irregular eye movements (H55)"],"isBillable":true,"fyEffectivity":{"fy2026":true,"fy2027":true,"billableFy2026":true,"billableFy2027":true},"sibling_codes":["H49","H49.0","H49.01","H49.02","H49.03","H49.1","H49.10","H49.11","H49.12","H49.2","H49.20","H49.21","H49.22","H49.23","H49.3","H49.30","H49.31","H49.32","H49.33","H49.4","H49.40","H49.41","H49.42","H49.43","H49.8","H49.81","H49.811","H49.812","H49.813","H49.819","H49.88","H49.881","H49.882","H49.883","H49.889","H49.9"],"inclusionTerms":[],"sibling_titles":{"code":"H49.9","title":"Unspecified paralytic strabismus","isBillable":true},"useAdditionalCode":[],"clinicalDefinition":"Fourth [trochlear] nerve palsy, bilateral is a billable ICD-10-CM diagnosis code (H49.13). Excludes2 (not included here): internal ophthalmoplegia (H52.51-); internuclear ophthalmoplegia (H51.2-); progressive supranuclear ophthalmoplegia (G23.1); nystagmus and other irregular eye movements (H55).","officialDefinition":"Fourth [trochlear] nerve palsy, bilateral is a billable ICD-10-CM diagnosis code (H49.13). Excludes2 (not included here): internal ophthalmoplegia (H52.51-); internuclear ophthalmoplegia (H51.2-); progressive supranuclear ophthalmoplegia (G23.1); nystagmus and other irregular eye movements (H55).","seventhCharacterInstructions":[],"workflowProtocols":[],"guidelines":{"whenToUse":[],"whenNotToUse":[],"commonBillingMistakes":[],"codeComparisons":[],"documentationChecklist":[]},"domainLandscape":{"summary":"Primary diagnostic domain and clinical landscape evaluation.","keyCategories":[],"diagnosticContinuum":"Progression continuum from acute presentation to resolution."},"children":[],"hierarchy":[],"relatedCodes":[],"relevantCPTCodes":[],"documentationTips":[],"caseStudies":[],"description":"","overview":""}