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A Study of Histopathological Features of Latanoprost-Treated Irides With or Without Darkening Compared With Non–Latanoprost-Treated Irides
Daniel M. Albert, MD, MS;
Ronald E. Gangnon, PhD;
Hans E. Grossniklaus, MD;
W. Richard Green, MD;
Soesiawati Darjatmoko, BS;
Amol D. Kulkarni, MD
Arch Ophthalmol. 2008;126(5):626-631.
Objectives To study the histopathological features of latanoprost-treated irides with or without darkening, compared with non–latanoprost-treated irides.
Methods Iridectomy specimens and patient history forms were independently examined by 3 ophthalmic pathologists in a masked fashion. Specimens were evaluated for premalignant changes and for differences in level of pigmentation and degrees of cellularity, inflammation, and vascular abnormalities.
Results The specimens consisted of 22 latanoprost-treated darkened irides, 35 latanoprost-treated irides without darkening, and 35 non–latanoprost-treated irides. There was a statistically significant decrease in the number of nuclear invaginations and prominent nucleoli in latanoprost-treated darkened irides compared with the other 2 groups (P = .004 and P = .005, respectively). The average thickness and pigmentation of the anterior border layer was greater in the latanoprost-treated darkened irides than in the other 2 groups (P = .03 and P = .02, respectively). The latanoprost-treated darkened irides had increased pigmentation of the stroma (P < .001), stromal fibroblasts (P < .001), melanocytes (P = .005), vascular endothelium (P = .02), and adventitia (P < .001) relative to the other 2 groups.
Conclusions There is no histopathological evidence of premalignant changes in latanoprost-treated darkened irides. The latanoprost-induced iris color changes are due to a thickening of the anterior border layer and an increased amount of melanin in the anterior border layer and within the stromal melanocytes.
Author Affiliations: Departments of Ophthalmology and Visual Sciences (Drs Albert and Kulkarni and Mr Darjatmoko) and Biostatistics and Medical Informatics (Dr Gangnon), University of Wisconsin School of Medicine and Public Health, Madison; and Departments of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia (Dr Grossniklaus), and Wilmer Eye Institute, The Johns Hopkins University, Baltimore, Maryland (Dr Green).
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