Lens Induced Glaucoma

Lens induced glaucoma includes several mechanisms of raised pressure caused by the crystalline lens:

• Phacolytic glaucoma: leakage of high molecular weight lens proteins through an intact capsule of a hypermature cataract, which are engulfed by macrophages that obstruct the trabecular meshwork. The angle is open.
• Phacomorphic glaucoma: an intumescent (swollen) mature cataract pushes the iris forward causing secondary pupillary block and angle closure (acute).
• Lens particle glaucoma: lens fragments after cataract surgery, capsulotomy or trauma obstruct the meshwork.
• Phacoantigenic (phacoanaphylactic) glaucoma: granulomatous inflammation against lens protein after capsule breach; may be accompanied by raised pressure.
• Dislocated lens: anterior dislocation causes pupillary block, and posterior dislocation can cause inflammation and glaucoma.
• Common in regions with delayed cataract surgery, where patients present with white, hypermature cataracts.

• Phacolytic: painful red eye with high pressure (40 to 70 mmHg) in an elderly person with long standing poor vision; corneal oedema, deep anterior chamber with cells, large cells and flare, white flocculent particles in the chamber and on the anterior lens capsule, no keratic precipitates, no synechiae, mature or Morgagnian cataract (dense white cortex, nucleus sinking inferiorly), open angle.
• Phacomorphic: acute angle closure picture with shallow chamber, mid-dilated pupil, hazy cornea, swollen white cataract, high pressure, pain, nausea.
• Lens particle: pressure rise days to weeks after surgery or trauma, with cortical debris and anterior chamber reaction.
• Phacoantigenic: granulomatous uveitis, mutton fat precipitates, synechiae, posterior capsule rupture history.

• Slit lamp examination with attention to lens (swelling, capsule integrity, fragments), anterior chamber depth (versus fellow eye) and angle.
• Gonioscopy of the fellow eye if cornea is hazy (also reveals tendency to angle closure).
• Tonometry; B-scan ultrasound if the posterior segment cannot be seen (to exclude tumour or retinal detachment before surgery).
• Anterior chamber aspiration for cytology (macrophages laden with lens material) if diagnosis is unclear.
• Exclude other causes of high pressure with a swollen lens (uveitic, neovascular).

• Lower pressure urgently: acetazolamide 500 mg intravenously then 250 mg orally four times daily, timolol 0.5 percent, brimonidine 0.2 percent, dorzolamide 2 percent, and mannitol 20 percent 1 to 1.5 g/kg intravenously for very high pressure. Do not use miotics in phacomorphic glaucoma (they increase block) and avoid in phacolytic glaucoma.
• Control inflammation: prednisolone acetate 1 percent every 1 to 2 hours, cycloplegic (atropine 1 percent twice daily or cyclopentolate 1 percent) for phacomorphic and phacoantigenic disease.
• Definitive treatment is lens removal once pressure and inflammation are controlled (within 24 to 72 hours):
  • Phacoemulsification or manual small incision extraction with trypan blue 0.06 percent capsule staining for white cataract, careful intraoperative techniques for weak zonules, and capsular tension ring.
  • Laser peripheral iridotomy first in phacomorphic glaucoma if the cornea is clear, to break the block temporarily.
  • Retained lens material: vitrectomy for large fragments in the vitreous.
• Intraocular lens implantation at the same time if inflammation and zonules allow.
• Postoperative: topical steroid, NSAID, and pressure monitoring; some eyes need glaucoma therapy because of residual trabecular damage.
• Examine the fellow eye and counsel on timely cataract surgery.