title: Trabecular-iris circumference volume in open angle eyes using swept-source fourier domain anterior segment optical coherence tomography.
abstract: Purpose. To introduce a new anterior segment optical coherence tomography parameter, trabecular-iris circumference volume (TICV), which measures the integrated volume of the peripheral angle, and establish a reference range in normal, open angle eyes. Methods. One eye of each participant with open angles and a normal anterior segment was imaged using 3D mode by the CASIA SS-1000 (Tomey, Nagoya, Japan). Trabecular-iris space area (TISA) and TICV at 500 and 750 µm were calculated. Analysis of covariance was performed to examine the effect of age and its interaction with spherical equivalent. Results. The study included 100 participants with a mean age of 50 (±15) years (range 20-79). TICV showed a normal distribution with a mean (±SD) value of 4.75 µL (±2.30) for TICV500 and a mean (±SD) value of 8.90 µL (±3.88) for TICV750. Overall, TICV showed an age-related reduction (P = 0.035). In addition, angle volume increased with increased myopia for all age groups, except for those older than 65 years. Conclusions. This study introduces a new parameter to measure peripheral angle volume, TICV, with age-adjusted normal ranges for open angle eyes. Further investigation is warranted to determine the clinical utility of this new parameter.
authors.affiliation: Robert Cizik Eye Clinic, 6400 Fannin Street, Suite 1800, Houston, TX 77030, USA.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Rigi
authors.affiliation: Robert Cizik Eye Clinic, 6400 Fannin Street, Suite 1800, Houston, TX 77030, USA ; Ruiz Department of Ophthalmology and Visual Science, The University of Texas Medical School at Houston, 6431 Fannin Street, MSB 7.024, Houston, TX 77030, USA.
authors.forename: Lauren S
authors.initials: LS
authors.lastname: Blieden
authors.affiliation: Robert Cizik Eye Clinic, 6400 Fannin Street, Suite 1800, Houston, TX 77030, USA ; Ruiz Department of Ophthalmology and Visual Science, The University of Texas Medical School at Houston, 6431 Fannin Street, MSB 7.024, Houston, TX 77030, USA ; Glaucoma Service, South Texas Veterans Healthcare System, 7400 Merton Minter, San Antonio, TX 78229, USA.
authors.forename: Donna
authors.initials: D
authors.lastname: Nguyen
authors.affiliation: Ruiz Department of Ophthalmology and Visual Science, The University of Texas Medical School at Houston, 6431 Fannin Street, MSB 7.024, Houston, TX 77030, USA.
authors.forename: Alice Z
authors.initials: AZ
authors.lastname: Chuang
authors.affiliation: Robert Cizik Eye Clinic, 6400 Fannin Street, Suite 1800, Houston, TX 77030, USA.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Baker
authors.affiliation: Robert Cizik Eye Clinic, 6400 Fannin Street, Suite 1800, Houston, TX 77030, USA ; Ruiz Department of Ophthalmology and Visual Science, The University of Texas Medical School at Houston, 6431 Fannin Street, MSB 7.024, Houston, TX 77030, USA.
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Bell
authors.affiliation: Robert Cizik Eye Clinic, 6400 Fannin Street, Suite 1800, Houston, TX 77030, USA ; Ruiz Department of Ophthalmology and Visual Science, The University of Texas Medical School at Houston, 6431 Fannin Street, MSB 7.024, Houston, TX 77030, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Lee
authors.affiliation: Ruiz Department of Ophthalmology and Visual Science, The University of Texas Medical School at Houston, 6431 Fannin Street, MSB 7.024, Houston, TX 77030, USA.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Mankiewicz
authors.affiliation: Robert Cizik Eye Clinic, 6400 Fannin Street, Suite 1800, Houston, TX 77030, USA ; Ruiz Department of Ophthalmology and Visual Science, The University of Texas Medical School at Houston, 6431 Fannin Street, MSB 7.024, Houston, TX 77030, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Feldman