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Editors Selection IGR 8-3
Clinical Forms of Glaucoma: Pigmentary glaucoma in Chinese
Comment by Jeffrey Liebmann on:
21689 Clinical signs and characteristics of pigmentary glaucoma in Chinese, Qing G; Wang N, Japanese Journal of Ophthalmology, 2008; 52: 162-166
Pigment dispersion syndrome (PDS) is characterized by the classic triad of increased, homogeneous trabecular pigmentation, vertical corneal endothelial pigment granule deposition (Krukenberg spindle), and midperipheral, radial iris transillumination defects. Other clinical features include a concave iris configuration that permits iridozonular contact and mechanical rupture of iris pigment epithelium with resultant pigment liberation and distribution within the anterior segment, pigment deposition in concentric rings in iris furrows, younger age of onset, myopia in most patients, and an increased risk for retinal breaks and rhegmatogenous retinal detachment. Most patients in the existing literature are European-derived and the disease is uncommon in individuals of African and East Asian ancestry. Pigment dispersion syndrome may lead to ocular hypertension and subsequent open angle glaucoma. When glaucomatous optic neuropathy is present, the disorder is termed pigmentary glaucoma (PG). In this retrospective chart review of all glaucoma patients treated at the Beijing Tongren Eye Hospital over a 14-year period (42,999 glaucoma patients), Qing and Wang (1123) identified 21 patients of Chinese ancestry with PDS or PG (0.049% of patients), confirming the rarity of this condition in East Asia.
One should consider the diagnosis of PDS or PG in all populations when increased trabecular pigmentation is evident on gonioscopyThe patients were characterizedby significant elevation of intraocular pressure (mean IOP was 34.5 mmHg), age < 40 years, myopia, increased trabecular pigmentation, pigment deposition on the zonules and lens and a concave iris configuration (documented by ultrasound biomicrcoscopy), but none of the patients exhibited the typical midperipheral, spoke-like, radial iris transillumination defects that are pathognomonic for this disorder in European-derived subjects with PG. The authors hypothesize that the increased amount of melanin in the iris pigment epithelium or other factors of iris morphology or physiology may tend to block retroillumination so that these defects may be visible only infrequently in this population. This article highlights the need to consider the diagnosis of PDS or PG in all populations when increased trabecular pigmentation is evident on gonioscopy.
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