SECONDARY OPEN-ANGLE GLAUCOMAS

Secondary Open-Angle Glaucomas

APHAKIC OR POSTKERATOPLASTY Glaucoma may develop from angle distortion or anatomic change or from PAS (especially postkeratoplasty), alpha-chymotrypsin, or zonule fragments (post-ICCE).

ELEVATED EPISCLERAL VENOUS PRESSURE (EVP) From venous obstruction (thyroid orbitopathy, superior vena cava syndrome, orbital tumors, cavernous sinus thrombosis), arteriovenous fistula (carotid–cavernous sinus fistula, Sturge-Weber syndrome), or idiopathic. Signs and symptoms: dilated and tortuous episcleral vessels, chemosis, proptosis, orbital bruit or pulsation, blood in Schlemm’s canal.

FUCHS’ ENDOTHELIAL DYSTROPHY 10 to 15% of Fuchs’ patients develop glaucoma; autosomal dominant disorder characterized by collagen deposition on Descemet’s membrane with bilateral corneal guttae, usually in late adulthood female patients.

GHOST CELL GLAUCOMA Vitreous hemorrhage usually following trauma, vitrectomy, or cataract extraction, with disruption of the anterior hyaloid face. The degenerated, tan, rigid, spherical RBCs clog the TM; may see Heinz bodies (hemoglobin congealed on the inside of the RBC cell membrane) on pathology. May need vitrectomy.

HEMOLYTIC GLAUCOMA TM obstructed by macrophages that have ingested RBCs after hyphema (usually traumatic: look for lens subluxation or phacodonesis). Old hemorrhage may also cause hemosiderotic glaucoma, or siderosis from hemoglobin iron may produce TM endothelial cell dysfunction.

MELANOMALYTIC GLAUCOMA Macrophages with melanin pigment from melanoma block the TM. Tumors may also seed or directly extend into the angle.

PHACOLYTIC GLAUCOMA Mature or hypermature cataract leaks high molecular weight proteins through an intact capsule; the proteins are then ingested by macrophages and clog the TM. Usually characterized by abrupt onset, with a red painful eye with AC flare and precipitates of white flocculent material, in the setting of a mature cataract. Control the inflammation and glaucoma, then remove lens.

PHACOTOXIC OR LENS PARTICLE GLAUCOMA Disrupted lens capsule (postoperative, YAG laser capsulotomy, trauma, etc.) in which the retained cortex and lens particles obstruct the TM. Characterized by delayed onset; may see white fluffy cortical material in AC and some inflammation, with

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an open angle on gonioscopy. Control IOP and inflammation; surgery may be needed. (Compare with phacoanaphylaxis, which is zonal granulomatous uveitis from disrupted lens capsule and usually has hypotony, not glaucoma.)

PIGMENT DISPERSION SYNDROME (PDS), PIGMENT DISPERSION GLAUCOMA (PDG) Autosomal dominant, chromosome 7q35–q36 defect of iris pigment epithelium, causing an iris that is too large for the eye. The iris has redundant folds and posterior bowing, with friction on the zonules, causing the release of pigment and signs of the syndrome. Profile: young, white, middle-aged, myopic male. Twenty-five to 45% of PDS patients develop pigmentary glaucoma from pigment granules that clog the TM and damage the TM endothelium. The increased AC IOP pushes the iris posterior, causing a reverse pupillary block.

Signs and symptoms: Krukenberg spindle (vertical layering of pigment on the corneal endothelium), midperipheral iris TID, peripheral concave iris (‘‘queer’’ iris configuration with wide 45 degree open angle), 360 degree heavily pigmented TM (almost black), Sampaolesis’s line, and Scheie’s stripe (posterior lens pigment settles where the anterior hyaloid face meets the posterior capsule). May see aliquots of aqueous enter the AC with blink or lid squeeze.

Treat with miotics, ALT, and traditional glaucoma therapy. Can follow TID as a marker for progression, and exercise may provoke dispersion. The reverse pupillary block needs very peripheral small PI that creates a ‘‘black hole’’ effect as aqueous rushes into the posterior chamber (PC), unlike the large peripheral iridectomy needed for narrow angle, in which aqueous and pigment rush out of the PC.

POST-TRAUMATIC GLAUCOMA May have immediate IOP rise from TM contusion or disruption, hyphema, massive choroidal hemorrhage, alkali chemical burn (initial IOP rise from scleral shrinkage and prostaglandin release; may have intermediate IOP increase from inflammation or late IOP elevation from TM damage or PAS). Delayed glaucoma from angle recession (decreased aqueous filtration, lifelong glaucoma risk), PAS, lens-induced (phacolytic, subluxation with pupillary block), ghost cell, closure of cyclodialysis cleft, epithelial downgrowth, or retained foreign body.

Seven rings of tissue that may be injured with anterior segment trauma (plus cataract):

Pupil margin tears

Iris root tear: iridodialyisis

CB muscle tear: angle recession

TM tears

Scleral spur tear: cyclodialysis cleft

Zonular dialysis

Ora serrata or vitreous base: dialysis

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Angle recession, contusion angle deformity: tear in the face of CB seen as a widened CB band (cleavage created between the circular and longitudinal ciliary muscles). Typically has a deep AC with iris retroplacement, and may be accompanied by iridoor cyclodialysis. Also has posterior rotation of the ciliary processes: a line drawn through the scleral spur parallel to the visual axis usually bisects the first ciliary process, but in angle recession, the line would pass anterior to the ciliary processes. Angle recession does not cause glaucoma but indicates trauma to the TM; thus, patients have a lifetime risk of

developing glaucoma. POAG is also a risk factor for development of angle recession glaucoma, and angle recession is treated like POAG when it develops.

Hyphema: glaucoma risk is greatest following rebleeding (average 4 days after traumatic hyphema from clot lysis and retraction) from either RBCs and fibrin that obstruct the TM or a pupillary clot that may cause a RPB. Hyphema glaucoma risk: large hyphema, initial hypotony, African-American race, aspirin use, and sickle cell hemoglobinopathy.

Iridodialysis: tear in root of iris; may need to be sutured in place if large, obstructing visual axis, or causing monocular diplopia.

Cyclodialysis: disinsertion of longitudinal ciliary muscle from scleral spur; see white, bare sclera underneath. Usually has hypotony from aqueous flow into suprachoroidal space, but may have sudden increased IOP if it closes spontaneously. May need to be sutured or closed with cryotherapy if it is causing chronic hypotony.

Descemetization: migration of Descemet’s membrane over TM after surgery or trauma. Presents like apparent POAG, as the membrane is opaque.

Epithelial ingrowth: devastating postoperative or post-traumatic complication from surface epithelium that proliferates into the eye. As it grows over the corneal endothelium, it causes segmental corneal edema, then progresses onto the TM, obstructing outflow. Epithelium induces underlying trabecular stoma to proliferate and thus changes the TM into fibrous tissue. Iris whitens with argon laser.

Fibrous ingrowth: not as severe as epithelial ingrowth.

PSEUDOEXFOLIATION SYNDROME (PXS) OR PSEUDOEXFOLIATIVE GLAUCOMA (PXG) Most common SOAG; 70% of PXS patients develop glaucoma (50% have bilateral glaucoma, often with labile IOP). A bilateral disease that presents unilaterally, it causes a BM-like fibrillogranular white material to be deposited throughout the anterior segment and also systemically. Glaucoma develops as the material blocks the TM or is ingested by macrophages that block the TM. The disease always occurs in the elderly, with the highest incidence in Navajo Native Americans (38% incidence) and Scandinavians.

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Signs: target or bull’s-eye lesion on the anterior lens capsule, ‘‘dandruff ’’ on the pupillary margin, poor dilation, peripupillary TID, nuclear cataract, zonular dehiscence (phacodonesis, subluxation, increased vitreous loss with cataract extraction), pigment dispersion with patchy ‘‘brown sugar’’ colored TM and Sampaolesi’s line.

Pathology: eosinophilic ‘‘iron filings’’ and ‘‘sawtoothing’’ of iris pigment epithelium.

PXG has a good response to ALT. Not cured by cataract extraction and remember poor zonular integrity with CE. Associated with increased incidence of chronic angle closure. Some call PXS ‘‘exfoliation’’ syndrome, however this is really ‘‘glassblower’s cataract.’’

SCHWARTZ SYNDROME Rare, mild, uveitic glaucoma from RRD (often chronic, low-lying RD), with degenerated photoreceptor outer segments that pass forward through disrupted anterior hyaloid face and obstruct the TM. Not responsive to steroids.

STEROID-INDUCED GLAUCOMA Five percent of normal patients within 2 to 3 weeks after starting steroids develop increased IOP that almost always returns to baseline when stopped. Risks include POAG, first-degree relative of POAG, diabetes, myopia, and nonfluorinated steroids. Increased IOP develops from decreased facility of outflow from steroid-induced increased GAG in the TM extracellular matrix.

Chromosome 1q defect found in the myocilin gene, as in JOAG. Some patients with the gene defect are steroid–responders, whereas others are not because of polymorphism (gene expressed differently in different individuals), and other genes regulate its expression.

UVEITIC GLAUCOMA Usually characterized by decreased IOP from aqueous production suppression and increased uveoscleral outflow. However, several uveitic syndromes are associated with increased IOP, notably herpetic uveitis and the following:

Fuchs’ HIC: unilateral, chronic, mild anterior uveitis with stellate KP; patients are usually 30 to 40 years old. Associated with hypochromia and cataract.

Posner-Schlossman syndrome (glaucomatocyclitic crisis): characterized by unilateral, recurrent, mild anterior uveitis in young adults, with marked IOP elevations from idiopathic trabeculitis.

Grant’s syndrome: bilateral trabecular precipitates in patients that may progress to full uveitis; treat with steroids.

Uveitis-glaucoma-hyphema syndrome (UGH): classic triad, but all parts may or may not be present. Usually from poorly positioned IOL (classically, AC IOL ‘‘tickles’’ the TM); may need lens exchange.

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