Pseudoexfoliation Glaucoma

Pseudoexfoliation (PEX) syndrome is an age related systemic disorder of abnormal extracellular matrix, with deposition of fibrillar grey white material on lens capsule, zonules, iris, trabecular meshwork and other ocular and extraocular tissues. Pseudoexfoliation glaucoma is the most common identifiable cause of secondary open angle glaucoma worldwide.

• Prevalence rises with age (over 60 years); highest in Scandinavia, Mediterranean regions and parts of southern Africa; often unilateral at presentation, with bilateral involvement developing in about 40 to 50 percent over 10 years.
• Genetic basis: LOXL1 gene variants. Material is also found in skin, heart, lung, vessels, and is linked with hearing loss, aortic aneurysm and cardiovascular disease.
• Glaucoma develops in about 15 to 40 percent of PEX eyes over 10 years (risk about 5 to 10 times higher than in controls), with higher pressures, wider fluctuation, faster progression and worse prognosis than primary open angle glaucoma.
• Mechanism: flakes and pigment obstruct the meshwork, and the material also damages the trabecular endothelium; weak zonules cause lens instability.

• Usually asymptomatic until glaucoma or cataract.
• Slit lamp: dandruff like material on the pupil margin, and a characteristic target pattern on the anterior lens capsule (central disc, clear zone, peripheral granular zone) seen after dilation; sphincter region transillumination defects, poor pupil dilation, and pigment on the endothelium and trabecular meshwork (Sampaolesi line).
• High intraocular pressure with large diurnal fluctuation (often 30 to 50 mmHg), disc cupping and field loss.
• Phacodonesis, subluxation of the lens, and zonular weakness; nuclear cataract; risk of intraoperative complications.
• Narrow angle in some eyes (forward lens movement).

• Dilated slit lamp examination (material is best seen after dilation) with examination of both eyes.
• Gonioscopy: open angle, heavy uneven pigmentation, Sampaolesi line, possible flakes.
• Tonometry (diurnal variation), disc examination, optical coherence tomography and perimetry.
• Careful lens assessment for zonular weakness (phacodonesis, asymmetry in anterior chamber depth) before cataract surgery; ultrasound biomicroscopy if needed.
• Check cardiovascular risk and blood pressure.

• Aim for lower target pressure than in primary open angle glaucoma because of faster progression (typically a 30 to 40 percent reduction).
• Medical: prostaglandin analogue at night (latanoprost 0.005 percent), timolol 0.5 percent twice daily, dorzolamide 2 percent three times daily, brimonidine 0.2 percent twice daily; the response often wanes over time.
• Laser: selective laser trabeculoplasty or argon laser trabeculoplasty gives a good initial response (more pronounced than in primary disease) but the effect may fade after 1 to 3 years; repeat is possible.
• Surgery: trabeculectomy with mitomycin C 0.2 to 0.4 mg/mL, glaucoma drainage devices, and combined phacoemulsification with trabeculectomy or minimally invasive procedures (trabecular bypass); phacoemulsification alone lowers pressure by a few mmHg.
• Cataract surgery precautions: expect poor dilation (iris hooks, pupil expansion ring, intracameral phenylephrine 1.5 percent with ketorolac), weak zonules (capsulorhexis of adequate size, capsular tension ring early, avoid stress on the capsule), risk of posterior capsule rupture and lens dislocation, and postoperative pressure spikes (viscoelastic removal). Late intraocular lens bag dislocation occurs years later.
• Follow every 3 to 4 months initially; examine the fellow eye every 6 to 12 months for conversion.
• Advise patients and surgeons about risks.