This page summarises the secondary causes of open-angle glaucoma. These conditions involve clogging of the trabecular meshwork where the angle is still open. This blocks aqueous outflow and leads to increased IOP, which subsequently leads to glaucoma.
Posner-Schlossman Syndrome
Recurrent unilateral episodes of acute IOP elevation.
Pathology
- Idiopathic episodic disease.
- Associations: CMV + H. pylori + HLA BW5.
Diagnostics
Presentation
- 20-year-old male + Unilateral + blurred vision + recurrent attacks + white eye.
Investigations
- IOP (40-80 mmHg) + open angle + no synechiae.
Management
- Topical steroids.
- IOP lowering (high → IV acetazolamide, medium/low → topical timolol).
Pseudoexfoliation Syndrome
Grey-white fibrillar deposits block the anterior chamber angle leading to secondary open-angle glaucoma.
Pathology
- Linked to a mutation in the LOXL1 (an enzyme that contributes to elastin formation) in Chr 15q24.1.
- Associations: hearing loss + Alzheimer's + high homocysteine + low folate intake.
Diagnostics
Presentation
- Scandinavian female of 50 years.
Investigations
- Elevated IOP + Glaucomatous vision changes + anterior lens capsule white deposits + Sampaolesi line.
Management
- As for POAG.
Pigment Dispersion Syndrome
An inherited autosomal dominant condition characterised by clogging of the trabecular meshwork by iris pigment.
Pathology
- Pigment dispersion syndrome = shedding of iris pigment throughout the anterior chamber.
- Pigment dispersion glaucoma = iris pigment clogs trabecular meshwork and leads to open-angle glaucomatous vision changes.
Diagnostics
Presentation
- Blurred vision on exertion.
Investigation
- Elevated IOP + Glaucomatous damage + TM pigmentation + Krukenberg spindles + Mid-peripheral spoke-like pigmentation.
Management
- Conservative: avoid exertion.
- Medical: Topical prostaglandins or pilocarpine before exercise.
- Surgical: Trabeculoplasty or trabeculectomy.
Phacolytic Glaucoma
Debris from hypermature cataracts can break off and clog the trabecular meshwork. This can lead to secondary open-angle glaucoma.
Diagnostics
Presentation
- Painful red eye.
- Pseudohypopyon.
Investigations
- AC tap → lens proteins and foamy macrophages.
- Slit-lamp → Anterior chamber flare + hypermature cataract.
Management
- Medical → topical IOP lowering medications following the same protocol as POAG.
- Definitive → cataract extraction.
Angle Recession Glaucoma
Ciliary body damage caused by blunt trauma can lead to chronic open-angle glaucoma. This is called angle recession glaucoma.
Pathology
- Blunt ocular trauma can rupture the ciliary body between the root of the iris and the scleral spur.
- Glaucoma is caused by damage to the trabecular meshwork and only develops in around 10% of patients over 10 years.
Diagnostics
Presentation
- History of ocular trauma.
Investigations
- Gonioscopy shows irregular widening of the ciliary body.
Red Cell and Ghost Cell Glaucoma
Cells can get trapped within the trabecular meshwork and lead to aqueous outflow obstruction, raised IOP and open-angle glaucoma.
Red Cell |
Ghost Cell |
|---|---|
Fresh red cells blocking the TM |
Degenerated old red cells blocking the TM |
Typically occurs acutely after hyphaema and blunt trauma |
Typically occurs a few weeks after vitreous haemorrhage |
Characteristic tan-coloured degenerating red cells can be seen in the anterior chamber in patients with ghost cell glaucoma.
Sturge-Weber Syndrome
A congenital neurocutaneous disorder which leads to glaucoma.
Pathology
- Anterior chamber malformation → glaucoma within first year of life.
- Increased episcleral venous pressure → glaucoma later in life.
Causes of raised episcleral venous pressure can also lead to raised IOP.
Diagnostics
Presentation
- Port wine stain + seizures + choroidal haemangiomas.
- Glaucomatous eye is ipsilateral to the stain.
Port wine stains are non-blanching pink/purple patches that do not cross the midline.
Management
- Early-onset → Goniotomy or trabeculectomy or combined trabeculotomy-trabeculectomy.
- Late-onset → Medical therapy first, then trabeculectomy if medical therapy fails.
