Orbital fat atrophy in glaucoma patients treated with topical bimatoprost can bimatoprost cause enophthalmos?

Purpose: The aim of this communication is to report enophthalmos as a possible new adverse effect of topical bimatoprost treatment. 3 Patients and Methods: A retrospective case series of five glaucoma patients under long-term topical bimatoprost treatment was evaluated. Documentation with photo and Hertel exophthalmometry was reviewed. Results: In all five patients a deep lid sulcus, reduced infraocular fat pads and enophthalmossuspicious Hertel values were found (mean 11.9mm; SD2.4). Other aetiologies for enophthalmos were excluded anamnestically and by clinical examination. Conclusion: Bimatoprost may lead to an alteration of the eyelid with deepening of the lid sulcus and may also be responsible for an iatrogenic orbital fat atrophy. A possible mechanism of action might be the induction of apoptosis of orbital fibroblasts with a remodelling of the extracellular matrix. Prospective studies are necessary to confirm this cross-sectional observation.