title: The use of time-lapse optical coherence tomography to image the effects of microapplied toxins on the retina.
abstract: OBJECTIVE
  We developed a novel technique for accelerated drug screening and retinotoxin characterization using time-lapse optical coherence tomography (OCT) and a drug microapplication device.
  
  
  METHODS
  Using an ex vivo rabbit eyecup preparation, we studied retinotoxin effects in real-time by microperfusing small retinal areas under a transparent fluoropolymer tube. Known retinotoxic agents were applied to the retina for 5-minute periods, while changes in retinal structure, thickness, and reflectance were monitored with OCT. The OCT images of two agents with dissimilar mechanisms, cyanide and kainic acid, were compared to their structural changes seen histologically.
  
  
  RESULTS
  We found the actions of retinotoxic agents tested could be classified broadly into two distinct types: (1) agents that induce neuronal depolarization, such as kainic acid, causing increases in OCT reflectivity or thickness of the inner plexiform and nuclear layers, and decreased reflectivity of the outer retina; and (2) agents that disrupt mitochondrial function, such as cyanide, causing outer retinal structural changes as evidenced by a reduction in the OCT reflectivity of the photoreceptor outer segment and pigment epithelium layers.
  
  
  CONCLUSIONS
  Retinotoxin-induced changes in retinal layer reflectivity and thickness under the microperfusion tube in OCT images closely matched the histological evidence of retinal injury. Time-lapse OCT imaging of the microperfused local retina has the potential to accelerate drug retinotoxicological screening and expand the use of OCT as an evaluation tool for preclinical animal testing.
authors.affiliation: Division of Biomedical Physics, Office of Science and Engineering Labs, Center for Devices and Radiological Health, Food and Drug Administration, White Oak Federal Research Labs, Silver Spring, Maryland, United States.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Majdi
authors.affiliation: National Eye Institute, Visual Function Core, National Institutes of Health, Bethesda, Maryland, United States.
authors.forename: Haohua
authors.initials: H
authors.lastname: Qian
authors.affiliation: National Eye Institute, Visual Function Core, National Institutes of Health, Bethesda, Maryland, United States.
authors.forename: Yichao
authors.initials: Y
authors.lastname: Li
authors.affiliation: Division of Biomedical Physics, Office of Science and Engineering Labs, Center for Devices and Radiological Health, Food and Drug Administration, White Oak Federal Research Labs, Silver Spring, Maryland, United States.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Langsner
authors.affiliation: Office of Testing and Research, Center for Drug Evaluation and Research, Food and Drug Administration, White Oak Federal Research Labs, Silver Spring, Maryland, United States.
authors.forename: Katherine I
authors.initials: KI
authors.lastname: Shea
authors.affiliation: Division of Biomedical Physics, Office of Science and Engineering Labs, Center for Devices and Radiological Health, Food and Drug Administration, White Oak Federal Research Labs, Silver Spring, Maryland, United States.
authors.forename: Anant
authors.initials: A
authors.lastname: Agrawal
authors.affiliation: Division of Biomedical Physics, Office of Science and Engineering Labs, Center for Devices and Radiological Health, Food and Drug Administration, White Oak Federal Research Labs, Silver Spring, Maryland, United States.
authors.forename: Daniel X
authors.initials: DX
authors.lastname: Hammer
authors.affiliation: Office of Testing and Research, Center for Drug Evaluation and Research, Food and Drug Administration, White Oak Federal Research Labs, Silver Spring, Maryland, United States.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Hanig
authors.affiliation: Division of Biomedical Physics, Office of Science and Engineering Labs, Center for Devices and Radiological Health, Food and Drug Administration, White Oak Federal Research Labs, Silver Spring, Maryland, United States.
authors.forename: Ethan D
authors.initials: ED
authors.lastname: Cohen
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D007608:Kainic Acid / Q000008:administration & dosage / Q000633:toxicity; D008297:Male; D011817:Rabbits; D012164:Retinal Diseases / Q000139:chemically induced / Q000473:pathology*; D055214:Retinal Photoreceptor Cell Outer Segment / Q000187:drug effects / Q000473:pathology*; D055213:Retinal Pigment Epithelium / Q000187:drug effects / Q000473:pathology*; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D007608:Kainic Acid
keywords: microperfusion; optical coherence tomography; retinotoxins