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Daniel K Roberts, Yongyi Yang, Ana Lukic, Jacob T Wilensky, Miles Wernick; Pupil Analysis in African-Americans with Long Anterior Lens Zonules. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4303.
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Long anterior zonules (LAZ), which are characterized by zonular fibers that extend more central than usual on the anterior lens capsule, could be be a risk factor for open- and narrow-angle glaucoma. Studies so far have shown LAZ to be associated with female gender, older age, hyperopia, shorter axial length, remnants of the tunica vasculosa lentis, and pigment dispersion. We investigated the hypothesis that LAZ are also more likely to have mild dyscoria, possibly due to chronic irido-zonular rubbing, concentrated mainly in the pupillary region.
We reviewed a near infrared iris transillumination (NIRit) database that contained a variety of subjects and selected LAZ and normal eyes for comparison. All eyes had been previously imaged using a modified digital camera (COOLPIX 950, Nikon Corp, Tokyo, Japan) to photograph the iris while it was illuminated with visible and infrared light via a standard ophthalmic transilluminator directed against the inferior eyelid. Pupil contour lines were created using an automated computer algorithm, and measures of pupil shape were calculated, including pupil roundness (PR), pupil ovalness (PO), pupil circularity index (PCI), pupil size (PS), and pupil eccentricity (PE). Regression analyses were used to assess pupil feature differences between LAZ and normal eyes. Because African-American females comprised the vast majority of LAZ eyes in the database, only this subject group was included in the analysis.
There were 41 LAZ females with a mean age = 68.3 years +/- 11.8 years (44-92 years) and 72 normals with a mean age = 45.0 years +/- 13.7 years (18-75 years). Controlling for age and pupil size (PS), LAZ right eyes showed PO measures (P=0.001), PR measures (P=0.002), and PCI measures (P=0.001) that were significantly different from normal right eyes. PE measures were marginally significantly different (P=0.03).
In addition to signs previously described, the clinical features of LAZ eyes may also include pupil dyscoria. This may be helpful toward the emerging understanding of the LAZ clinical trait.
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