AIM CONCEPT INTEGRATION
4th Year MBBS • EYE Module
Topic 9 — Angle-Closure, Secondary Glaucoma & Treatment
:contentReference[oaicite:0]{index=0}
Connect the mechanism, examination findings, investigations and treatment choices into one rapid revision pathway.
1. THE TOPIC IN ONE CONNECTED FLOW
The glaucomas in this topic arise from different causes, but all finally interfere with aqueous drainage. Primary angle closure results from iris-related angle obstruction, while neovascular and lens-induced glaucomas use secondary mechanisms. The key is to connect the cause → outflow problem → pressure rise → clinical finding → investigation → mechanism-directed treatment.
STAGE 1
Predisposition or Trigger
Narrow anterior segment • retinal ischemia • abnormal cataractous lens
→
STAGE 2
Core Mechanism
Pupillary block • VEGF-driven fibrovascular growth • lens crowding or protein leakage
→
STAGE 3
Outflow Obstruction
Peripheral angle closure or trabecular blockage reduces aqueous drainage
→
STAGE 4
Pressure & Ocular Change
IOP rises → corneal edema, pain and progressive risk of optic-nerve damage
→
STAGE 5
Diagnostic Clue
Gonioscopy + tonometry + iris, lens or fundus findings identify the mechanism
→
STAGE 6
Mechanism-Directed Treatment
Lower IOP + iridotomy, retinal ischemia treatment or removal of the lens cause
→
STAGE 7
Outcome
Early control protects vision; persistent IOP elevation can produce glaucomatous optic neuropathy
2. KEY CLINICAL CONNECTIONS
Acute Primary Angle Closure
Narrow angle + pupillary block → iris bombé and abrupt trabecular obstruction → very high IOP → painful red eye, corneal edema, reduced vision and mid-dilated pupil.
Clinical pattern → urgent pressure reduction → definitive laser peripheral iridotomy when the eye is stabilized.
Neovascular Glaucoma
Retinal ischemia → VEGF release → rubeosis iridis and angle neovascularization → fibrovascular obstruction → later synechial angle closure.
Ischemic drive → PRP ± anti-VEGF; high IOP → aqueous suppressants and surgery when refractory.
Lens-Induced Glaucoma
Phacomorphic: swollen lens → shallow chamber → secondary angle closure. Phacolytic: hypermature lens → leaked proteins/macrophages → trabecular blockage with relatively deep chamber.
Both pathways → initial IOP/inflammation control → definitive removal of the causative lens.
3. AIM HIGH-YIELD INTEGRATION REVIEW
⭐ PACS → PAC → PACG: anatomical angle risk → pressure-related angle damage/PAS → glaucomatous optic-nerve damage.
⭐ Pupillary block → posterior chamber pressure rises → iris bows forward → angle closes → acute IOP elevation.
Tonometry measures pressure, while gonioscopy identifies whether the drainage angle is open, appositionally closed or permanently synechially closed.
⭐ Acute angle closure → rapid pressure lowering is urgent, but iridotomy corrects the pupillary-block mechanism; iridoplasty helps persistent peripheral iris crowding.
Retinal ischemia → VEGF → rubeosis → fibrovascular angle disease; PRP treats the ischemic source while anti-VEGF rapidly suppresses neovascularization.
⭐ Phacomorphic = bulky lens + shallow closed angle; phacolytic = leaked lens proteins + relatively deep open angle.
Drug logic: beta-blockers, alpha-2 agonists and carbonic anhydrase inhibitors reduce aqueous production; prostaglandin analogues mainly increase uveoscleral outflow.
Persistent uncontrolled glaucoma → trabeculectomy or drainage device; refractory painful eye with poor visual potential → cyclodestructive treatment may reduce aqueous production.
AIM Exam Trap: An acute angle-closure attack describes the clinical emergency; the term primary angle-closure glaucoma requires established glaucomatous optic-nerve damage.