Changes to upper eyelid orbital fat from use of topical bimatoprost, travoprost, and latanoprost

To confirm the possible mechanism by which topical prostaglandin antiglaucoma drugs cause a deep superior sulcus. Among patients who used bimatoprost (Lumigan), latanoprost (Xalatan), or travoprost (Travatan) and who developed a deep upper lid sulcus, 18 eyes of 11 patients (mean age, 58.2 +/- 8.9 years) were studied. Seven patients were binocular users of one of the eye drops and four were monocular users. Preaponeurotic orbital fat was obtained, and the mean adipocyte density compared. Results: In the four monocular users, mean adipocyte density of treated eyes was 1758.21 +/- 158.15 cells/mm(2), and that of untreated eyes was 1258.73 +/- 127.54 cells/mm(2). This difference was statistically significant (P = 0.04), suggesting that the adipocytes were atrophied in the treated eyes. The mean adipocyte density of the bimatoprost group was 2073.35 +/- 184.89 cells/mm(2), that of the travoprost group was 1623.46 +/- 218.99 cells/mm(2), and that of the latanoprost group was 1468.20 +/- 113.44 cells/mm(2). The densities of the bimatoprost and travoprost groups, but not of the latanoprost group (P = 0.75), were significantly different from that of the untreated group (P < 0.001). Fat atrophy can be considered a mechanism of upper eyelid sulcus deepening in patients using topical prostaglandin analogs.