a SciTechnol journal Research Article Hwang et al., Int J Ophthalmic Pathol 2013, 2:4 http://dx.doi.org/10.4172/2324-8599.1000125 International Publisher of Science, Technology and Medicine International Journal of Ophthalmic Pathology All articles published in International Journal of Ophthalmic Pathology are the property of SciTechnol, and is protected by copyright laws. Copyright © 2013, SciTechnol, All Rights Reserved. Assessment of the Anterior Chamber Angle after Trabectome Glaucoma Surgery by Optical Coherence Tomography, Histopathology, Ultrasound Biomicroscopy, and Scanning Electron Microscopy Jeremy C Hwang 1 , Kay T Khine 2 , Narsing A Rao 1 , Don S Minckler 3 , Farnaz Memarzadeh 1 , Yan Li 4 , David Huang 4 , Brian A Francis 1 * Abstract Purpose: To provide high resolution in vitro and in vivo characterization of the post-Trabectome anterior chamber angle. Patients and Methods: We used scanning electron microscopy (SEM) to obtain high resolution images of the post-Trabectome angle in cadaver eyes. We then characterized trabecular meshwork strips removed during the procedure using histopathology. Finally, we imaged the post-Trabectome angle in two patients using optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM). Results: Assessment of the anterior chamber after Trabectome surgery with SEM demonstrates the complete unrooing of Schlemm’s canal by ablating and removing the overlying trabecular beams. The removal of the trabecular meshwork allows direct access of aqueous low to the collector channels. Histopathology of a trabecular meshwork strip removed during surgery demonstrates minimal mechanical or thermal damage to the removed tissue. Anterior segment OCT as well as UBM performed on patients who underwent Trabectome surgery demonstrate a new trabecular cleft. Conclusion: SEM, histopathology, OCT, and UBM allowed for in vitro and in vivo characterization and veriication of the proposed mechanism of the Trabectome procedure. UBM and OCT provide a method for clinicians to objectively assess the anatomical effect of the Trabectome procedure, and may allow for objective comparison across patients and surgeons. Keywords Trabectome; Post-trabectome anterior chamber angle; Trabecular cleft; Trabecular beams; Schlemm’s canal; Trabecular meshwork; Trabeculectomy ab interno *Corresponding author: Brian Francis, Doheny Eye Institute, 1450 San Pablo Street, DEI 4804, Los Angeles, CA 90033, USA, Tel: 323-442-6454; Fax: 323- 442-6412; E-mail: bfrancis@usc.edu Received: September 27, 2012 Accepted: October 03, 2013 Published: October 17, 2013 Abbreviations: FD-OCT: Fourier Domain Optical Coherence Tomography; H&E: Hematoxylin and Eosin; IOP: Intraocular Pressure; OCT: Optical Coherence Tomography; POAG: Primary Open Angle Glaucoma; SEM: Scanning Electron Microscopy; TM: Trabecular Meshwork; UBM: Ultrasound Biomicroscopy Introduction A major risk factor for the development of glaucomatous optic nerve damage in primary open angle glaucoma (POAG) is elevated intraocular pressure (IOP), which is believed to result in part from reduced facility of aqueous outlow through the trabecular meshwork (TM). he Trabectome (NeoMedix Corp., San Juan Capistrano, CA) is a recently-developed surgical instrument which selectively removes the TM and inner wall of Schlemm’s canal via a gonioscopically guided approach (trabeculectomy ab interno), allowing direct access of the aqueous to the collector channels [1-3]. While post-Trabectome changes to the angle have been well-characterized in cadaver eyes with histopathological analysis [3], there have been no reports, to our knowledge, of in vivo angle characterization post-Trabectome. In this study, we provide high resolution in vitro and in vivo characterization of the post-Trabectome anterior chamber angle. Patients and Methods SEM Normal reference of trabecular meshwork and Schlemm’s canal and post-Trabectome images were obtained with SEM using standard protocols. he Trabectome procedure was performed by treating approximately 90 degrees of the nasal angle on donated normal human cadaver eyes at the Mayo Clinic. hese eyes did not have evidence of glaucoma or other signiicant eye disease. Histopathology Histopathological analysis of the TM strip removed during Trabectome surgery was performed by the pathology laboratory at USC Doheny Eye Institute. Trabectome surgery using previously- published protocols was performed on a patient (Case1), and the TM strip removed during surgery was ixed in formalin and stained with hematoxylin and eosin (H&E) stain and prepared for microscopic analysis using standard protocols. Anterior segment OCT Fourier domain optical coherence tomography (FD-OCT) RTVue FD-OCT (Optovue, Inc., Fremont, CA) was used to image the anterior segment of a patient (Case 2) six months ater undergoing Trabectome procedure. UBM UBM (VuMAX TM UBM, Sonomed Escalon, Lake Success, NY) was performed using standard manufacturer protocols on a patient (Case 1) 3 months ater Trabectome procedure. Patients Normal reference: he nasal angle of a healthy 32 year old Asian