Page 57 - 21st Century Perspective - Glaucoma Supplement
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these defects. Of note, patients with ocular albinism also have iris retroillumination defects, but here
the entire iris homogeneously transilluminates, giving a uniformly pink color to the entire iris.
The obvious separation between pigment dispersion syndrome and pigmentary glaucoma is the
presence of increased IOP and optic neuropathy in pigmentary glaucoma.
Because of the unique iris anatomy in pigment dispersion disease, the “sagging” iris tends to be
deep and concave in its posterior bowing configuration, and this accentuates the iris pigment
chaffing from the posterior iris epithelium. Because of a relative pupillary block, the pressure in the
anterior chamber can be slightly higher than the pressure in the posterior chamber. This results in
more iris concavity, potentiating posterior iris epithelial chaffing and liberation of pigmented cells.
This mechanism explains why laser photoiridotomy is commonly helpful in decreasing or halting
further zonular chaffing of the iris epithelium; the laser opening in the peripheral iris permits the
pressure in the posterior and anterior chamber to become equal, which then permits the effect of the
relative pupillary block to be neutralized, thus allowing the iris diaphragm to move anteriorly enough
to diminish or halt the pigment dispersion process. It is important to note that such laser therapy can
be effective in mitigating the dynamics of the dispersion process but has limited or no therapeutic
benefit once pigmentary glaucoma has developed.
Therapy for pigmentary glaucoma is similar to that of primary open-angle glaucoma.
Pseudoexfoliation syndrome and pseudoexfoliation glaucoma
Just as pigment dispersion syndrome can progress to pigmentary glaucoma, pseudoexfoliation
syndrome can progress to pseudoexfoliation glaucoma. Similarly, both syndromes are commonly
present for years before causing increased IOP, and ultimately, glaucomatous optic neuropathy.
Both disease pathways involve a four-step process:
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