{"id":"F2025L01298","name":"Statement of Principles concerning optochiasmatic arachnoiditis (Balance of Probabilities) (No. 96 of 2025)","slug":"statement-of-principles-concerning-optochiasmatic-arachnoiditis-balance-of-probabilities-no-96-of-20","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":443018,"registerId":"F2025L01298-fast-fetch-1775957932712","compilationNumber":null,"startDate":"2026-04-12","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"Statement of Principles concerning optochiasmatic arachnoiditis (Balance of Probabilities) (No. 96 of 2025)","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\n![RMA Australian Government Coat of Arms](image.001.jpeg)\n\n \n\nStatement of Principles\n\nconcerning\n\nOPTOCHIASMATIC ARACHNOIDITIS  (Balance of Probabilities)\n\n(No. 96 of 2025)\n\nThe Repatriation Medical Authority determines the following Statement of Principles under subsection 196B(3) of the Veterans' Entitlements Act 1986.\n\n \n\nDated 24 October 2025\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\nProfessor Terence Campbell AM\n\nChairperson\n\nby and on behalf of\n\nThe Repatriation Medical Authority\n\n \n\n   \n\n\nContents\n\n1 Name\n\n2 Commencement\n\n3 Authority\n\n4 Repeal\n\n5 Application\n\n6 Definitions\n\n7 Kind of injury, disease or death to which this Statement of Principles relates\n\n8 Basis for determining the factors\n\n9 Factors that must exist\n\n10 Relationship to service\n\n11 Factors referring to an injury or disease covered by another Statement of Principles\n\nSchedule 1 - Dictionary\n\n1 Definitions\n\n \n\n \n\n\n\n\n1.                Name\n\n\nThis is the Statement of Principles concerning optochiasmatic arachnoiditis (Balance of Probabilities) (No. 96 of 2025).\n\n1.                Commencement\n\n\n              This instrument commences on 24 November 2025.\n\n1.                Authority\n\n\nThis instrument is made under subsection 196B(3) of the Veterans' Entitlements Act 1986.\n\n1.                Repeal\n\n\nThe Statement of Principles concerning optochiasmatic arachnoiditis (Balance of Probabilities) (No. 58 of 2016) (Federal Register of Legislation No. F2016L00568) made under subsections 196B(3) and (8) of the VEA is repealed.\n\n1.                Application\n\n\nThis instrument applies to a claim to which section 120B of the VEA or section 339 of the Military Rehabilitation and Compensation Act 2004 applies.\n\n1.                Definitions\n\n\nThe terms defined in the Schedule 1 - Dictionary have the meaning given when used in this instrument.\n\n1.                Kind of injury, disease or death to which this Statement of Principles relates\n  1.           This Statement of Principles is about optochiasmatic arachnoiditis and death from optochiasmatic arachnoiditis.\n\n\nMeaning of optochiasmatic arachnoiditis\n\n1.           For the purposes of this Statement of Principles, optochiasmatic arachnoiditis means chronic inflammation of the arachnoid membrane surrounding the optic chiasm and intracranial optic nerves, resulting in damage to these structures from fibrosis and the formation of adhesions, and typically presenting with progressive visual loss.\n\n\nDeath from optochiasmatic arachnoiditis\n\n1.           For the purposes of this Statement of Principles, optochiasmatic arachnoiditis, in relation to a person, includes death from a terminal event or condition that was contributed to by the person's optochiasmatic arachnoiditis.\n\n\nNote: terminal event is defined in the Schedule 1 – Dictionary.\n\n1.                Basis for determining the factors\n\n\nOn the sound medical‑scientific evidence available, the Repatriation Medical Authority is of the view that it is more probable than not that optochiasmatic arachnoiditis and death from optochiasmatic arachnoiditis can be related to relevant service rendered by veterans or members of the Forces under the VEA, or members under the MRCA.\n\nNote: MRCA, relevant service and VEA are defined in the Schedule 1 – Dictionary.\n\n1.                Factors that must exist\n\n\nAt least one of the following factors must exist before it can be said that, on the balance of probabilities, optochiasmatic arachnoiditis or death from optochiasmatic arachnoiditis is connected with the circumstances of a person's relevant service:\n\n1.           having a tuberculosis infection of the leptomeninges surrounding the optic chiasm or intracranial optic nerves before clinical onset or clinical worsening.\n2.            being treated with antibiotics for tuberculous meningitis at least 30 days before clinical onset or clinical worsening\n3.           having a subarachnoid haemorrhage or bleeding into the subarachnoid space before clinical onset or clinical worsening.\n4.           having muslin or cotton wrapping or packing, left in situ after a surgical procedure which involves or adjacent to the optic chiasm, at least 30 days before clinical onset or clinical worsening. \n5.           having received a cumulative equivalent dose of at least 60 sieverts of ionising radiation to the region of the optic chiasm before clinical onset or clinical worsening.\n\n\nNote: cumulative equivalent dose is defined in the Schedule 1 - Dictionary.\n\n1.           having an intrathecal myelogram or intrathecal treatment with iophendylate (Pantopaque or Myodil) before clinical onset or clinical worsening.\n2.           inability to obtain appropriate clinical management for optochiasmatic arachnoiditis before clinical worsening.\n\n\n1.            Relationship to service\n  1.           The existence in a person of any factor referred to in section 9, must be related to the relevant service rendered by the person.\n  2.           The clinical worsening aspect of factors set out in section 9 apply only to material contribution to, or aggravation of, optochiasmatic arachnoiditis where the person's optochiasmatic arachnoiditis was suffered or contracted before or during (but did not arise out of) the person's relevant service.\n2.            Factors referring to an injury or disease covered by another Statement of Principles\n\n\nIn this Statement of Principles:\n\n1.           if a factor referred to in section 9 applies in relation to a person; and\n2.           that factor refers to an injury or disease in respect of which a Statement of Principles has been determined under subsection 196B(3) of the VEA;\n\n\nthen the factors in that Statement of Principles apply in accordance with the terms of that Statement of Principles as in force from time to time.\n\n \n\n \n\nSchedule 1 - Dictionary  \n\nNote:               See Section 6\n\n1               Definitions\n\nIn this instrument:\n\n                             cumulative equivalent dose means the total dose of ionising radiation received by the particular organ or tissue from external exposure, internal exposure or both, apart from normal background radiation exposure in Australia, calculated in accordance with the methodology set out in Guide to calculation of 'cumulative equivalent dose' for the purpose of applying ionising radiation factors contained in Statements of Principles determined under Part XIA of the Veterans' Entitlements Act 1986 (Cth), Australian Radiation Protection and Nuclear Safety Agency, as in force on 2 August 2017.\n\nNote 1: Examples of circumstances that might lead to exposure to ionising radiation include being present during or subsequent to the testing or use of nuclear weapons, undergoing diagnostic or therapeutic medical procedures involving ionising radiation, and being a member of an aircrew, leading to increased levels of exposure to cosmic radiation.\n\nNote 2: For the purpose of dose reconstruction, dose is calculated as an average over the mass of a specific tissue or organ. If a tissue is exposed to multiple sources of ionising radiation, the various dose estimates for each type of radiation must be combined.\n\n                             MRCA means the Military Rehabilitation and Compensation Act 2004.\n\n                               optochiasmatic arachnoiditis—see subsection 7(2).\n\n                             relevant service means:\n\n(a)          eligible war service (other than operational service) under the VEA;\n\n(b)          defence service (other than hazardous service and British nuclear test defence service) under the VEA; or\n\n(c)          peacetime service under the MRCA.\n\nNote: MRCA and VEA are also defined in the Schedule 1 - Dictionary.\n\n                             terminal event means the proximate or ultimate cause of death and includes the following:\n\n(a)           pneumonia;\n\n(b)           respiratory failure;\n\n(c)           cardiac arrest;\n\n(d)           circulatory failure; or\n\n(e)           cessation of brain function.\n\n                             VEA means the Veterans' Entitlements Act 1986.\n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a straightforward replacement instrument maintaining the established scope of Repatriation Medical Authority Statements of Principles. It continues the long-standing framework of listing specific aetiological factors for rare conditions, with no expansion beyond the original purpose of determining service connection for veteran compensation claims."},"complexity_factors":["Highly specialised medical terminology throughout (optochiasmatic arachnoiditis, leptomeninges, intrathecal myelogram, iophendylate)","Cross-references to two separate Acts (VEA and MRCA) and incorporates definitions from external documents (ARPANSA radiation dose calculation guide from 2017)","Conditional logic requiring precise temporal relationships ('at least 30 days before', 'before clinical onset or clinical worsening')","Dual application structure — distinguishes between causing the condition versus worsening an existing condition","Nested definitions: 'terminal event' defined with five sub-categories, 'relevant service' excludes operational/hazardous service creating negative conditions","Only 7 defined terms in dictionary but heavy reliance on external technical standards for radiation dose calculation"],"plain_english_summary":"This instrument updates the rules for when Australian veterans can claim compensation for optochiasmatic arachnoiditis, replacing the 2016 version. It sets a strict, medical-legal checklist (seven specific scenarios) and uses the \"balance of probabilities\" test to link the condition to service.\n\nIt applies to veterans and defence members claiming under the VEA or MRCA for non-operational service. Its narrow criteria mean many with this diagnosis may be unable to establish service causation unless their history matches the listed scenarios."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"This instrument expressly repeals the earlier Statement of Principles (No. 58 of 2016) and substitutes a new Statement (s4). It applies to claims under section 120B of the VEA or section 339 of the MRCA (s5). The instrument itself lists the specific factors that, if related to a person’s relevant service, suffice on the balance of probabilities to establish a service connection (s9, s10). The source text does not state within the instrument whether the substantive coverage differs from the repealed instrument; assessing substantive change requires comparison with the repealed Statement."},"complexity_factors":["Technical medical terminology and diagnostic concepts (optochiasmatic arachnoiditis, tuberculous meningitis, subarachnoid haemorrhage) requiring clinical interpretation (s7(2), s9).","Multiple temporally framed causal conditions: factors must precede clinical onset or clinical worsening; some require a minimum 30‑day interval (s9).","A quantitative radiation threshold: cumulative equivalent dose ≥ 60 sieverts to the optic chiasm, with dose reconstruction methodology referenced to an external ARPANSA guide (Schedule 1 definition of cumulative equivalent dose).","Cross‑reference to other Statements of Principles where a listed factor is itself an injury or disease covered elsewhere (s11).","Legal standard of proof set as balance of probabilities and the requirement that identified factors be related to ‘relevant service’ (s8, s10(1)).","Replaces a prior instrument (No. 58 of 2016), so practitioners must note the repeal and any procedural/coverage differences (s4).","Application limited to claims under specified statutory provisions (section 120B of the VEA or section 339 of the MRCA), linking medical findings to entitlement processes (s5).","Inclusion of death from the condition via contribution to a terminal event widens causal pathways to mortality determinations (s7(3); Schedule 1 terminal event).","Some factors refer to prior treatments or retained surgical materials (intrathecal iophendylate, retained muslin/cotton), which may require historical clinical records and expert assessment (s9)."],"plain_english_summary":"This instrument sets the medical criteria the Repatriation Medical Authority uses to decide if optochiasmatic arachnoiditis (a chronic inflammation around the optic chiasm causing progressive vision loss) is connected to a veteran’s or service member’s relevant service. It replaces the 2016 Statement and applies to claims under the VEA and MRCA. The listed factors (for example, prior tuberculous meningitis, certain surgeries, radiation dose thresholds) determine whether a service link exists for entitlement purposes."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/statement-of-principles-concerning-optochiasmatic-arachnoiditis-balance-of-probabilities-no-96-of-20","history":"/api/acts/statement-of-principles-concerning-optochiasmatic-arachnoiditis-balance-of-probabilities-no-96-of-20/history","analysis":"/api/acts/statement-of-principles-concerning-optochiasmatic-arachnoiditis-balance-of-probabilities-no-96-of-20/analysis","conflicts":"/api/acts/statement-of-principles-concerning-optochiasmatic-arachnoiditis-balance-of-probabilities-no-96-of-20/conflicts","importantCases":"/api/acts/statement-of-principles-concerning-optochiasmatic-arachnoiditis-balance-of-probabilities-no-96-of-20/important-cases","documents":"/api/acts/statement-of-principles-concerning-optochiasmatic-arachnoiditis-balance-of-probabilities-no-96-of-20/documents"}}