title: In Vivo Effects of Retrobulbar Bimatoprost Injection on Orbital Fat.
abstract: Recent publications have reported the adverse effects of prostaglandin analogues on the periocular tissues. These medications may cause periorbital lipodystrophy, enophthalmos, and deepening of the superior sulcus deformity. While these effects may have adverse consequences for some patients, the atrophy of the periorbital fat may have a useful role in diseases that lead to orbital and periorbital fat hypertrophy such as thyroid eye disease. In this pilot study, the authors investigated the effects of retrobulbar bimatoprost injection on the intraocular pressure and orbital fat in a rat animal model.
  
  
  
  Three rats were sedated and intraocular pressure was measured. A 0.1 ml aliquot of bimatoprost was injected into the right orbit of all rats. In the left orbit, 0.1 ml of phosphate-buffered saline was injected as a control. Three weeks later, all rats were sedated and intraocular pressure was measured before euthanizing. Routine histologic staining was performed and thin sections through the intraconal orbital fat were obtained. Density of intraconal adipocytes was measured and adipocyte heterogeneity was determined using a computer image analysis algorithm.
  
  
  
  The specimens injected with bimatoprost demonstrated atrophy of orbital fat with significantly increased adipocyte density (p = 0.009) and heterogeneity (p = 0.008) when compared with control. Intraocular pressure was not significantly decreased at 3 weeks after injection of retrobulbar bimatoprost.
  
  
  
  In this pilot study, orbital injection of bimatoprost demonstrated atrophy of intraconal adipocytes when compared with control orbits injected with saline. The orbits injected with bimatoprost were noted to have smaller, more heterogeneous adipocytes that were densely packed in the intraconal space. The study limitations include the small sample size, which limited the ability for us to make conclusions about the effect on intraocular pressure. Nevertheless, the findings presented suggest that retrobulbar bimatoprost may present a nonsurgical alternative to induce atrophy of the orbital fat without inducing inflammation or hypotony.
authors.affiliation: Division of Ophthalmic Plastic and Reconstructive Surgery, Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.|FM Kirby Center for Molecular Ophthalmology, Stellar-Chance Laboratories, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Kian
authors.initials: K
authors.lastname: Eftekhari
authors.affiliation: Division of Oculoplastic, Orbital and Reconstructive Surgery, Department of Ophthalmology, University of California, San Francisco, San Francisco, California.
authors.forename: M Reza
authors.initials: MR
authors.lastname: Vagefi
authors.affiliation: Department of Ophthalmology, Scheie Eye Institute.
authors.forename: Vivian
authors.initials: V
authors.lastname: Lee
authors.affiliation: Department of Bioengineering, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: James Z
authors.initials: JZ
authors.lastname: Hui
authors.affiliation: General Robotics, Automation, Sensing & Perception (GRASP) Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Menglong
authors.initials: M
authors.lastname: Zhu
authors.affiliation: FM Kirby Center for Molecular Ophthalmology, Stellar-Chance Laboratories, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Dine
authors.affiliation: Oculoplastic Surgery, Inc., Salt Lake City, Utah.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Anderson
authors.affiliation: Harrison Department of Surgical Research, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, U.S.A.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Koeberlein
authors.affiliation: FM Kirby Center for Molecular Ophthalmology, Stellar-Chance Laboratories, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Reas
authors.initials: R
authors.lastname: Sulaimankutty
authors.affiliation: FM Kirby Center for Molecular Ophthalmology, Stellar-Chance Laboratories, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.|Department of Ophthalmology, Scheie Eye Institute.
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Shindler
mesh_terms: D017667:Adipocytes / Q000187:drug effects; D000273:Adipose Tissue / Q000187:drug effects*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D000069580:Bimatoprost / Q000494:pharmacology*; D004195:Disease Models, Animal; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D009915:Orbit / Q000187:drug effects*; D010865:Pilot Projects; D051381:Rats; D011917:Rats, Inbred Lew
chemical_list: D000959:Antihypertensive Agents; D000069580:Bimatoprost