Unification hypothesis of pigment dispersion syndrome

Department of Ophthalmology, New York Eye and Ear Infirmary, New York, USA.
Transactions of the American Ophthalmological Society 02/1996; 94:381-405; discussion 405-9.
Source: PubMed


To synthesize recent findings regarding pigment dispersion syndrome in order to arrive at a hypothesis concerning the nature of an underlying genetic predisposition.
The literature on the subject was reviewed and analyzed.
Eyes with pigment dispersion syndrome differ from normal in that they have a larger iris, a midperipheral posterior iris concavity that increases with accommodation, a more posterior iris insertion, increased iridolenticular contact that is reversed by inhibition of blinking, possibly an inherent weakness of the iris pigment epithelium, and an increased incidence of lattice degeneration of the retina.
A gene affecting some aspect of the development of the middle third of the eye early in the third trimester appears at the present time to be the most likely cause.

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    • "High intraocular pressure (IOP) is a major risk factor contributing to glaucoma [1]. Pigment dispersion syndrome (PDS) is a common condition that results in the dispersion of iris pigment into the anterior chamber (AC) [2,3]. The dispersed pigment accumulates within the ocular drainage structures, resulting in IOP elevation and glaucoma in some but not all individuals with PDS [4-8]. "
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    ABSTRACT: The molecular mechanisms causing pigment dispersion syndrome (PDS) and the pathway(s) by which it progresses to pigmentary glaucoma are not known. Mutations in two melanosomal protein genes (Tyrp1b and GpnmbR150X) are responsible for pigment dispersing iris disease, which progresses to intraocular pressure (IOP) elevation and subsequent glaucoma in DBA/2J mice. Melanosomal defects along with ocular immune abnormalities play a role in the propagation of pigment dispersion and progression to IOP elevation. Here, we tested the role of specific immune components in the progression of the iris disease and high IOP. We tested the role of NK cells in disease etiology by genetically modifying the B6.D2-GpnmbR150X Tyrp1b strain, which develops the same iris disease as DBA/2J mice. Our findings demonstrate that neither diminishing NK mediated cytotoxic activity (Prf1 mutation) nor NK cell depletion (Il2rg mutation) has any influence on the severity or timing of GpnmbR150X Tyrp1b mediated iris disease. Since DBA/2J mice are deficient in CD94, an important immune modulator that often acts as an immune suppressor, we generated DBA/2J mice sufficient in CD94. Sufficiency of CD94 failed to alter either the iris disease or the subsequent IOP elevation. Additionally CD94 status had no detected effect on glaucomatous optic nerve damage. Our previous data implicate immune components in the manifestation of pigment dispersion and/or IOP elevation in DBA/2J mice. The current study eliminates important immune components, specifically NK cells and CD94 deficiency, as critical in the progression of iris disease and glaucoma. This narrows the field of possible immune components responsible for disease progression.
    Full-text · Article · Mar 2014 · BMC Genetics
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    • "He concluded that the cause of the pigment loss was a mechanical rubbing of the iris pigment epithelium against anterior zonular bundles. Ritch (1996) has suggested that the pigment loss is based on an inherent weakness of the iris pigment epithelium. A typical sign in PDS and PG is a concavity of the iris (Davidson et al. 1983). "
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    ABSTRACT: Purpose: To study the effect of exercise on the configuration of the anterior chamber angle in healthy persons.Methods: Both eyes of 22 healthy persons were scanned by Ultrasound Biomicroscopy. Before and after 10 minutes of exercise the anterior chamber angle and the area of the peripheral anterior chamber were measured on the scannings.Results: After exercise the anterior chamber angle/peripheral area increases in all eyes due to changes in the iris configuration. The myopic group shows the largest change.Conclusion: Reverse pupillary block (iris concavity) is not pathognomonic in pigmentary glaucoma, it occurs in all normal eyes after exercise, most pronounced in myopics. Consequently, the difference between physiological and pathological reverse pupillary block has to be clarified.
    Full-text · Article · Jan 2002 · Acta Ophthalmologica Scandinavica
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