A study of histopathological features of latanoprost-treated irides with or without darkening compared with non-latanoprost-treated irides.
OBJECTIVE
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.
Albert
Daniel M
DM
Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, K6/412 Clinical Science Center, 600 Highland Ave, Madison, WI 53792-4673, USA. dalbert@wisc.edu
Gangnon
Ronald E
RE
Grossniklaus
Hans E
HE
Green
W Richard
WR
Darjatmoko
Soesiawati
S
Kulkarni
Amol D
AD
D000959:Antihypertensive Agents / Q000009:adverse effects*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000473:pathology; D005347:Fibroblasts / Q000187:drug effects / Q000473:pathology; D005901:Glaucoma / Q000188:drug therapy; D006801:Humans; D032801:Iridectomy; D007498:Iris / Q000187:drug effects*; D007499:Iris Diseases / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology*; D000077338:Latanoprost; D008543:Melanins / Q000378:metabolism; D008544:Melanocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D008548:Melanosis / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology*; D011461:Prostaglandins F, Synthetic / Q000009:adverse effects*
D000959:Antihypertensive Agents; D008543:Melanins; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost