Question

How does management of primary angle closure glaucoma differ from that of open angle glaucoma?

Hint:

PACG requires immediate treatment to lower IOP and prevent optic nerve damage, while OAG is managed long-term with medications and regular monitoring.

Answer 1

Step 1: Management of Primary Angle Closure Glaucoma vs. Open Angle Glaucoma.
The management of primary angle closure glaucoma (PACG) and open-angle glaucoma (OAG) differs significantly due to the underlying mechanisms of each condition.
(1) Primary Angle Closure Glaucoma (PACG):
- Acute Management: The primary goal is to lower the intraocular pressure (IOP) rapidly. This is done using a combination of the following:
- Topical Medications: Beta-blockers (e.g., timolol) or alpha agonists (e.g., apraclonidine) are used to reduce IOP.
- Oral Medications: Acetazolamide (carbonic anhydrase inhibitor) and glycerin (osmotic agent) are used to reduce IOP.
- Hyperosmotic Agents: Mannitol may be used intravenously to lower IOP in acute cases.
- Pupil Control: Pilocarpine is used to constrict the pupil and open the angle, although it is not always effective in acute PACG due to the severe angle closure.
- Laser Therapy: After the acute episode, a laser iridotomy is performed to create a permanent hole in the peripheral iris, allowing for aqueous humor to flow more freely into the anterior chamber.
- Surgical Intervention: If laser iridotomy fails, surgical iridectomy or goniosynechiolysis may be considered.
(2) Open-Angle Glaucoma (OAG):
- Long-Term Management: OAG is characterized by a gradual increase in IOP due to impaired aqueous humor outflow through the trabecular meshwork, leading to optic nerve damage over time. The treatment focus is on lowering IOP to prevent further damage.
- Topical Medications: Prostaglandin analogs (e.g., latanoprost), beta-blockers (e.g., timolol), alpha agonists (e.g., brimonidine), and carbonic anhydrase inhibitors (e.g., dorzolamide) are commonly prescribed to reduce IOP.
- Laser Therapy: Laser trabeculoplasty may be used to improve aqueous humor outflow through the trabecular meshwork.
- Surgical Options: Trabeculectomy or glaucoma drainage devices may be considered if medical therapy fails to control IOP.
Step 2: Key Differences in Management:
- Acute vs. Chronic: PACG often requires acute management to lower IOP and restore normal drainage, whereas OAG is a chronic condition managed with long-term medications to maintain a lower IOP.
- Surgical Intervention: In PACG, laser iridotomy is used as a preventive treatment, whereas in OAG, surgical interventions are considered only if medications and laser therapy fail to control IOP.