A Study of Iridectomy Histopathologic Features of Latanoprost- andNon–Latanoprost-Treated Patients

Abstract

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 pros-taglandin 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 (PϽ.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.

The Clinical Impact and Incidence of Periocular Pigmentation Associated with either Latanoprost or Bimatoprost Therapy

“…Importantly, no malignant histological changes were observed. 21 Alm and coworkers recently reported clinical followup over five years. In 380 patients from the original regulatory trials, they observed that the number of adverse events did not differ between those patients with or without iris color change.…”

Incidence of a Latanoprost-Induced Increase in Iris Pigmentation in Japanese Eyes

“…There is a possibility of maltransformation of melanocytes as well as increased intraocular pressure due to pigmentation at the trabecular meshwork, which might decrease aqueous outflow. 8 Although no such complications have yet been reported, 6,[9][10][11] Arranz-Marquez et al 12 reported more changes in the iris than a simple increase in the melanin content of the melanocytes by histopathologic examination. Therefore, careful follow-up of patients with increased iris pigmentation by latanoprost treatment is necessary.…”

Glaucomas Secondary to Intraocular Melanomas

“…However, it has been shown that prostaglandin analogs do not increase the number of melanocytes (Albert, 2004). Histopathologic features of iridectomy specimens of patients on latanoprost were examined and found that latanoprost-induced iris color change was due to an increased amount of melanin within the melanocytes (Albert, 2004). No statistically significant increase was found in the number of melanocytes (Albert, 2004).…”

“…Some concern regarding the use of prostaglandin analogs in patients with intraocular melanomas may exist. However, it has been shown that prostaglandin analogs do not increase the number of melanocytes (Albert, 2004). Histopathologic features of iridectomy specimens of patients on latanoprost were examined and found that latanoprost-induced iris color change was due to an increased amount of melanin within the melanocytes (Albert, 2004).…”