Pigmentary Dispersion Syndrome and Pigmentary Glaucoma
Hopefully by the time you read this spring is in the air, and another winter is behind us. The winter Olympics have concluded, and some serendipitous investigation has inspired this month’s Snapshot column (see Krukenberg’s Connection to the Olympics).
Krukenberg’s Connection to the Olympics
Friedrich Ernst Krukenberg (1871-1946) identified a pigment accumulation of the corneal endothelium, now known as Krukenberg spindle, in 1899. As an avid skier, he moved to Lake Geneva, Switzerland, to retire and ski the Swiss Alps. Krukenberg befriended and trained with Gustav Lantschner, who won a silver medal in the 1936 Winter Olympics.
PIGMENTARY CONDITIONS
Pigmentary dispersion syndrome (PDS) is characterized by anatomic variation of the iris and lens, which creates increased friction between these structures. This leads to pigment liberation and the creation of the medical triad of PDS;1 specifically, Krukenberg spindle (Figure 1), radial midperipheral iris transillumination defects (Figure 2), and pigment accumulation in the trabecular meshwork.1
The risk of developing pigmentary glaucoma (PG) from PDS is estimated to be between 35% and 50%.1 Myopia is found in about 80% of patients with PDS and is a significant risk factor.1 PG is more frequent in young White men, with an average age of diagnosis between 40 and 50 years; much younger than the typical age of patients with glaucoma. PG is rare in Black and Asian populations.1
PDS is reported to have an autosomal dominant inheritance with incomplete penetrance.1 Hopefully with the increase in genetic markers and genetic testing in eye care, we will be able to better screen the offspring of our patients with PG and give them a risk profile, allowing for earlier detection of disease and therapeutic intervention.
MANAGEMENT WITH A DROP
Pilocarpine has been a buzzword in eye care lately. Its role in PDS and PG cannot be overlooked; in addition to more typical glaucoma therapies, such as selective laser trabeculoplasty, laser peripheral iridotomy, and our arsenal of topical medications. By inducing miosis, we can limit the exercise-induced pigment release and subsequent increase in IOP for our Olympic-hopeful patients with PG.1 However, because of pilocarpine’s induced spasm of accommodation, it is unlikely to be tolerated by pre-presbyopic patients. The use of lower or micro-dosed pilocarpine, if available, may be better tolerated in terms of adverse effects. There appears to be an increased prevalence of retinal lattice degeneration, retinal breaks, and retinal detachments in patients with PG; however, Scheie et al did not find an increased incidence in patients treated with pilocarpine.1,2
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