title: Changes in morphology and optical properties of sclera and choroidal layers due to hyperosmotic agent.
abstract: Light scattering in the normally white sclera prevents diagnostic imaging or delivery of a focused laser beam to a target in the underlying choroid layer. In this study, we examine optical clearing of the sclera and changes in blood flow resulting from the application of glycerol to the sclera of rabbits. Recovery dynamics are monitored after the application of saline. The speed of clearing for injection delivery is compared to the direct application of glycerol through an incision in the conjunctiva. Although, the same volume of glycerol was applied, the sclera cleared much faster (5 to 10 s) with the topical application of glycerol compared to the injection method (3 min). In addition, the direct topical application of glycerol spreads over a larger area in the sclera than the latter method. A diffuse optical spectroscopy system provided spectral analysis of the remitted light every two minutes during clearing and rehydration. Comparison of measurements to those obtained from phantoms with various absorption and scattering properties provided estimates of the absorption coefficient and reduced scattering coefficient of rabbit eye tissue.
authors.affiliation: The University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712-0238, USA. raiyan_zaman@yahoo.com
authors.forename: Raiyan T
authors.initials: RT
authors.lastname: Zaman
authors.forename: Narasimhan
authors.initials: N
authors.lastname: Rajaram
authors.forename: Brandon S
authors.initials: BS
authors.lastname: Nichols
authors.forename: Henry G
authors.initials: HG
authors.lastname: Rylander
authors.forename: Tianyi
authors.initials: T
authors.lastname: Wang
authors.forename: James W
authors.initials: JW
authors.lastname: Tunnell
authors.forename: Ashley J
authors.initials: AJ
authors.lastname: Welch
mesh_terms: D000818:Animals; D001810:Blood Volume / Q000187:drug effects; D002829:Choroid / Q000033:anatomy & histology* / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism; D003952:Diagnostic Imaging / Q000379:methods / Q000706:statistics & numerical data; D003941:Diagnostic Techniques, Ophthalmological / Q000706:statistics & numerical data; D005260:Female; D005990:Glycerol / Q000008:administration & dosage*; D008027:Light; D008543:Melanins / Q000378:metabolism; D023421:Models, Animal; D055620:Optical Phenomena; D009994:Osmolar Concentration; D010100:Oxygen / Q000097:blood; D019047:Phantoms, Imaging; D011817:Rabbits; D012044:Regression Analysis; D012542:Scattering, Radiation; D012590:Sclera / Q000033:anatomy & histology* / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism; D013057:Spectrum Analysis / Q000379:methods / Q000706:statistics & numerical data
chemical_list: D008543:Melanins; D005990:Glycerol; D010100:Oxygen