A study of iridectomy histopathologic features of latanoprost- and non-latanoprost-treated patients.
OBJECTIVE
To examine the histopathologic features of iridectomy specimens from patients undergoing glaucoma surgery and to compare histologic abnormalities in a group of patients with a history of latanoprost therapy with those in a group of patients who had no history of prostaglandin therapy (controls).


METHODS
Iridectomy specimens and patient history forms were submitted to the central Latanoprost Pathology Center. These were independently examined by 3 ophthalmic pathologists in a masked fashion. Specimens were evaluated for malignant, premalignant, and other changes including differences in levels of pigmentation, degrees of cellularity, inflammation, vascular abnormalities, and changes in the iris pigment epithelium.


RESULTS
Specimens were received from 449 patients with a history of latanoprost treatment and 142 patients who had no history of treatment with latanoprost or other prostaglandin analogues. No evidence of malignant or premalignant changes was found. In latanoprost-treated irides, the prevalence of iris freckles was higher (P = .001) than in control irides, as was the combined number of stromal fibroblasts and melanocytes (P<.001). In a subgroup of specimens received through June 2002, there was no significant difference in mean melanocyte counts (P=.35) obtained by immunohistochemical staining techniques between the latanoprost-treated and control groups.


CONCLUSIONS
These findings support previous studies indicating that latanoprost-induced eye color changes are due to an increased amount of melanin within the iris stromal melanocytes. The increased numbers of freckles may be a focal manifestation of this effect.
Albert
Daniel M
DM
Department of Ophthalmology and Visual Sciences, University of Wisconsin Medical School, Madison, USA. dalbert@wisc.edu
Gangnon
Ronald E
RE
Zimbric
Michele L
ML
Damico
Christine M
CM
Fisher
Marian R
MR
Gleiser
Joel
J
Grossniklaus
Hans E
HE
Green
W Richard
WR
D000959:Antihypertensive Agents / Q000009:adverse effects* / Q000627:therapeutic use; D005127:Eye Color; D005260:Female; D005901:Glaucoma / Q000188:drug therapy* / Q000601:surgery; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D032801:Iridectomy; D007498:Iris / Q000187:drug effects* / Q000473:pathology* / Q000601:surgery; D000077338:Latanoprost; D008297:Male; D008543:Melanins / Q000378:metabolism; D008544:Melanocytes / Q000187:drug effects / Q000378:metabolism; D008548:Melanosis / Q000139:chemically induced* / Q000473:pathology; D011461:Prostaglandins F, Synthetic / Q000009:adverse effects* / Q000627:therapeutic use
D000959:Antihypertensive Agents; D008543:Melanins; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost