12-phase flow (12)

1. 1FRAME
   Frame POAG as a chronic, progressive optic neuropathy where the SINGLE evidence-based modifiable risk factor is IOP. The engine drives confirmation of OPEN angle, baseline structural + functional damage, agent-gated IOP-lowering ladder with SLT first-line per LiGHT (PMID 30862377 / 41043781), and progression-rate-aware escalation. Acute angle closure and other secondary glaucomas are recognised and routed OUT by engine_id (AAO PPP POAG 2025).
   advance: POAG framing set; route-out engine_ids noted
2. 2ENTRY
   Most entries are asymptomatic-screening or referral-triggered (high IOP, suspect disc on routine exam, family history); a minority present with already-advanced field loss. Confirm OPEN angle on gonioscopy and document IOP (Goldmann, both eyes) to establish untreated baseline before any therapy (AAO PPP POAG 2025).
   inputs: intraocular_pressure_goldmann, gonioscopy_open_angle
   advance: open angle confirmed; baseline IOP documented
3. 3CONTEXT
   Calibrate the pretest map: central corneal thickness (thin CCT under-reads IOP and is itself an independent risk factor — OHTS-validated), race / age, family history, myopia, vascular co-morbidity (hypotension, sleep apnoea — normal-tension association), chronic-corticosteroid exposure (steroid-induced secondary OAG must be unmasked) (AAO PPP POAG 2025).
   inputs: central_corneal_thickness_pachymetry, race_and_age, chronic_corticosteroid_exposure_history
   advance: risk profile + steroid-exposure screen complete
4. 4RED_FLAGS
   Screen the look-alikes that route OUT by engine_id: closed/occludable angle on gonioscopy → ophtho.acute-angle-closure-glaucoma.core.v1; uveitic / hyphaemic / neovascular secondary OAG → upstream engine; rapidly progressive disc cupping with optic-nerve pallor disproportionate to cup-disc ratio → compressive / inflammatory optic neuropathy work-up (not POAG).
   inputs: gonioscopy_open_angle
   advance: mimics screened; secondary causes routed by engine_id if present
5. 5INITIAL_WORKUP
   Baseline structural + functional assessment: OCT-RNFL + macular ganglion-cell complex, optic-disc photograph / imaging, Humphrey 24-2 standard automated perimetry (>=2 reliable baseline fields; 10-2 added when central threat). Stage severity by Hodapp-Anderson-Parrish (mild MD>-6 dB / moderate -6 to -12 / advanced <-12), which sets the IOP-reduction target (>=20-30% mild-moderate; >=40% advanced) (AAO PPP POAG 2025).
   inputs: oct_rnfl_and_macular_gcc, humphrey_24_2_visual_field, optic_disc_photo_or_imaging
   advance: baseline OCT + 2 reliable VFs + disc photo documented; HAP severity stage assigned
6. 6BRANCHING_WORKUP
   Pattern-directed branch: pseudoexfoliation deposits (lens / pupil) → faster-progressing pseudoexfoliative OAG (lower target IOP, earlier MIGS); Krukenberg spindle + iris transillumination + pigment in trabecular meshwork → pigmentary glaucoma (younger myopic men, exercise-related IOP spikes); IOP <22 with characteristic disc / field loss → normal-tension glaucoma (target >=30-40% IOP reduction, screen vascular risk, sleep-apnoea, nocturnal hypotension); IOP rise in a steroid user → steroid-induced OAG (taper / switch steroid first) (AAO PPP POAG 2025).
   inputs: pigment_dispersion_or_pseudoexfoliation_findings
   advance: POAG subtype assigned
7. 7DIFFERENTIAL
   Terminal differential: POAG (open angle, glaucomatous disc + RNFL + field, no secondary cause) vs ocular hypertension (raised IOP, normal disc + field — OHTS-stratified for prophylactic treatment) vs normal-tension glaucoma (IOP-low subtype, vascular risk) vs pseudoexfoliative OAG vs pigmentary OAG vs steroid-induced OAG vs uveitic/neovascular/post-traumatic secondary OAG (route to ophtho.uveitis or ophtho.acute-angle-closure-glaucoma) vs non-glaucomatous optic neuropathy (pallor>cup, neuro-imaging) (AAO PPP POAG 2025).
   advance: single best diagnosis assigned; secondary causes routed by engine_id
8. 8RISK_STRATIFICATION
   Combine HAP severity stage + rate of OCT/VF change (eyes lose RNFL ~0.5 microns/y normally; >1 micron/y or >0.5 dB/y MD loss is progression) + disc haemorrhage + central-corneal-thickness + life-expectancy + adherence ability. This yields the IOP target (>=20-30% mild/moderate, >=40% advanced/normal-tension), the urgency of treatment, and the surgical threshold (AAO PPP POAG 2025).
   inputs: humphrey_24_2_visual_field
   advance: IOP target + progression rate + surgical threshold defined
9. 9TREATMENT
   Tiered IOP-lowering ladder gated on contraindications and progression rate. Tier 1: SELECTIVE LASER TRABECULOPLASTY (SLT) is the first-line therapy per LiGHT (Gazzard Lancet 2019 PMID 30862377; 6-y Montesano/Gazzard Ophthalmology 2025 PMID 41043781) — 74.2% drop-free at 3 y, 0 glaucoma surgeries vs 11 in drop-arm, slower 6-y VF MD progression -0.26 vs -0.37 dB/y (P=0.007). Tier 2: topical prostaglandin analogue (latanoprost / travoprost / bimatoprost / tafluprost — most potent monotherapy, once-daily, iris/lash pigmentation + periocular fat atrophy side-effects) or latanoprostene-bunod (NO-donor PG). Tier 3: add a second class (β-blocker / α2-agonist / topical CAI) gated on systemic contraindications. Tier 4: fixed-combinations + ROCK-inhibitor (netarsudil) for adherence. Tier 5: MIGS (iStent, Hydrus, GATT, Xen gel-stent, Preserflo microshunt) commonly combined with cataract surgery. Tier 6: trabeculectomy or aqueous-shunt (Ahmed / Baerveldt) for refractory/advanced disease (AAO PPP POAG 2025).
   inputs: asthma_copd_bradycardia_heart_block, pediatric_or_under_2_years, pregnancy_or_breastfeeding
   advance: tier started; contraindications respected; IOP target documented
10. 10DISPOSITION
    Almost entirely outpatient ophthalmology / optometry co-management. Same-day glaucoma-specialist referral for: very high untreated IOP (>30) with advanced field loss, suspected acute angle closure (route OUT), or steroid-induced IOP spike not responding to medical therapy. Otherwise routine ophthalmology follow-up per progression risk (AAO PPP POAG 2025).
    advance: disposition documented; specialist route-in confirmed for high-risk subgroup
11. 11MONITORING
    At every visit: IOP, adherence + technique audit (the commonest cause of perceived treatment failure), side-effects review (PGA periocular changes, β-blocker pulse/lung, brimonidine drowsy + allergic conjunctivitis, CAI taste, ROCK conjunctival hyperaemia). Q6-12 mo: OCT-RNFL + GCC + Humphrey 24-2 (more frequent in moderate-advanced; >=5 fields in first 2 y to establish progression direction). Q1-2 y: optic-disc photo. Watch disc haemorrhage at every visit — strong progression signal (AAO PPP POAG 2025).
    inputs: adherence_and_technique
    advance: monitoring cadence + adherence audit + side-effect screen running
12. 12FOLLOWUP
    Lifelong therapy with stage-appropriate cadence. Escalate IOP target or step up the ladder if progression detected on OCT or VF despite hitting IOP target. Drop-burden reduction via SLT re-treatment or MIGS is appropriate in stable patients with adherence struggles. Co-manage steroid-induced OAG by taper/switch of the offending steroid in collaboration with the prescribing service. Counsel patients on driving-vision regulations, fall-risk in advanced disease, low-vision rehabilitation (AAO PPP POAG 2025).
    advance: long-term follow-up plan + low-vision considerations documented