Latanoprost iris pigmentation

The ocular adverse effects of latanoprost include conjunctival hyperemia, iris pigmentation, periocular skin color changes, anterior uveitis, and cystoid macular edema in pseudophakic patients (77,78). H. simplex dendritic keratitis has been reported after treatment with latanoprost (79). In patients with uveitic glaucoma, latanoprost can cause increased intraocular pressure and recurrence of inflammation (80). 

The mechanism of iris pigmentation due to latanoprost is unknown. In an in vitro experiment using uveal melanocytes, the addition of latanoprost increased melanin content, melanin production, and tyrosinase activity (18). Alpha-methyl-para-tyrosine, an inhibitor of tyrosinase (the enzyme that transforms tyrosine to levodopa), completely prevented the latanoprost-induced stimulation of melanogenesis. 

A 62-year old Korean woman treated with latanoprost for 4 months developed eyelid pigmentation in both upper and lower eyelids of both eyes (33). There was no increase in iris pigmentation. The eyelid pigmentation gradually diminished after withdrawal, but minimal brownish coloration remained along the lower eyelid folds in both eyes at 4 months. 

Lai IC, Kuo MT, Teng IMC. Iris pigment epithelial cyst induced by topical administration of latanoprost. Br J Ophthalmol 2003 87 366. 

Travoprost causes changes in iris pigmentation (3.1-5.0%) and changes in eyelash characteristics, including length, thickness, density, and color (44-57%), similar to those described with latanoprost, after 12 months (1). 

The use of unoprostone in the treatment of open-angle glaucoma and ocular hypertension has been reviewed (1). Most of the literature is in Japanese. The adverse effects of unoprostone are similar to those of latanoprost conjunctival hyperemia, iris pigmentation, hypertrichosis and hyperpigmentation of eyelashes, and rarely systemic effects (1). 

The mechanism of iris pigmentation due to latanoprost is unknown. In an in vitro experiment using uveal... 

Latanoprost, travoprost, and bimatoprost cause increased pigmentation of the iris in some patients after prolonged treatment (3.0-4.5 months) (71). Most data have been obtained with latanoprost, and it appears that there is a predisposition to iris pigmentation in patients with eyes of hazel or heterochromic color. As latanoprost and travoprost are selective agonists at PGF2a receptors, it is likely that the phenomenon is mediated by these receptors. Latanoprost stimulates melanogenesis in iris... 

Prostaglandin analogues Latanoprost Bimatoprost Unoprostone Travoprost Inaease aqueous outflow Blurry vision, conjunctival hyperemia, iris pigmentation, increase in eyelash length and coarseness... 

In long-term clinical use, prostanoids are known to cause iris pigmentation as a characteristic side-effect this has been observed in 5-15% of patients treated [27], In cultured melanoma cells, a carboxylic acid of latanoprost has been reported to increase melanogenesis [45], However, a carboxylic acid of tafluprost did not have the stimulatory effects... 

Adverse reactions to latanoprost have been studied in 115 children who had used latanoprost for a mean of 20 months [42. The reported adverse reactions were eyelash growth (in all eyes exposed for at least 6 months latanoprost was withdrawn in one case), conjunctival hyperemia/irritation ( = 6 two withdrawn), headache (n = 3), and difficulty in focusing iris pigmentation, and sleep disturbances ( = 1 each). 

Ophthalmic - Latanoprost-associated ocular adverse events reported at an incidence of 5% to 15% included the following Blurred vision, burning and stinging, conjunctival hyperemia, foreign body sensation, itching, increased pigmentation of the iris, punctate epithelial keratopathy. 

Pigmentation is expected to increase as long as latanoprost is administered but after discontinuation, pigmentation of the iris is likely to be permanent, while pigmentation of the periorbital tissue and eyelash changes has been reported as reversible. 

The success of latanoprost has stimulated development of similar prostanoids with ocular hypotensive effects, and bimatoprost, travaprost, and unoprostone are now available. These drugs act at the FP receptor and are administered as drops into the conjunctival sac once or twice daily. Adverse effects include irreversible brown pigmentation of the iris and eyelashes, drying of the eyes, and conjunctivitis. 

Similar to latanoprost and travoprost, bimatoprost has been reported to cause changes to pigmented tissues. These reports include pigmentation of the iris and periorbital tissue (eyelid). These changes may be permanent. The long-term effects on the melanocytes and the consequences of potential injury to the melanocytes and/or deposition of pigment granules to other areas of the eye are imknown. 

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