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OBJECTIVES: Aqueous melanin granules may be accurately quantified with the laser flare-cell meter and have been demonstrated to be increased in primary pigment dispersion syndrome (PDS). The aim of this study was to correlate intraocular pressure, glaucomatous damage of the optic nerve head, and visual field defects with the number of aqueous melanin granules in PDS. DESIGN: A cross-sectional study. PARTICIPANTS: Thirty-nine eyes of 21 patients with PDS and either ocular hypertension or pigmentary glaucoma. MAIN OUTCOME MEASURES: A 24-hour intraocular pressure (IOP) profile, automated perimetry (Octopus G1), and analysis of photostereographs and HRT (Heidelberg Retina Tomograph) images of the optic disc were performed. Aqueous melanin granules were quantified using the cell count mode of the laser flare-cell meter (KOWA FC-1000) with undilated and dilated pupils. Granule counts were correlated with maximum and mean IOP, maximum range (amplitude) of IOP, mean defect of automated perimetry (G1-program), and damage to the optic disc was measured with the HRT. RESULTS: The number of aqueous melanin granules showed a strong correlation with maximum IOP in both undilated (r=0.72, p < 0.001) and dilated eyes (r=0.5, p=0.02). A marginal correlation was found with the IOP range (r=0.43, p=0.04) and the mean defect of automated perimetry (r=0.41, p=0.06) in undilated eyes. The mean IOP and HRT measurements of the optic disc (area, volume of the neuroretinal rim, third moment in contour) showed no statistically significant correlation with the number of aqueous melanin granules (r < 0.4, p>0.2). CONCLUSIONS: A larger number of aqueous melanin granules is strongly associated with high IOP and also with visual field loss, providing additional evidence of the relationship between aqueous melanin dispersion and the development of pigmentary glaucoma. Quantification of aqueous melanin granules with the laser flare-cell meter might be useful for the evaluation of treatment effects, including laser iridotomy, in patients with PDS.
Dr. C.Y. Mardin, Department of Ophthalmology and University Eye Hospital, University of Erlangen-Nürnberg, Erlangen, Germany
9.4.3.1 Pigmentary glaucoma (Part of: 9 Clinical forms of glaucomas > 9.4 Glaucomas associated with other ocular and systemic disorders > 9.4.3 Glaucomas associated with disorders of the iris and ciliary body)