Feasibility of laser-targeted photoocclusion of the choriocapillary layer in rats

Sanjay Asrani, Shazhou Zou, Salvatore D'Anna, Gerard Lutty, Stanley A. Vinores, Morton F. Goldberg, Ran Zeimer

Research output: Contribution to journalArticle

Abstract

Purpose. A new method, laser-targeted photoocclusion, was developed to occlude choroidal neovascularization while minimizing damage to the overlying retina. The ability to occlude normal choriocapillary layer in rats was evaluated as a first test of the feasibility of treating choroidal neovascularization with this method. Method. A photosensitive agent, aluminum phthalocyanine tetrasulfonate, encapsulated in heat-sensitive liposomes, was administered intravenously along with carboxyfluorescein liposomes. A low- power argon laser (retinal power density of 5.7 W/cm2) locally released a photosensitizer bolus, monitored by the simultaneous release of carboxyfluorescein. A diode laser (operating at 675 nm with a retinal power density of 0.27 W/cm2) activated the photosensitizer with its release. Results. Vessels in the choriocapillary layer were occluded at day 3 after laser treatment and remained unchanged during the 30-day follow-up. Larger choroidal vessels and retinal capillaries remained perfused. Control experiments excluded possible effects of heat or activation of free photosensitizer. Pilot histologic studies showed no damage to the retinal pigment epithelium. Conclusions. Laser-targeted photoocclusion caused selective occlusion of normal choriocapillaries while sparing overlying retinal pigment epithelium and retinal vessels. The method has potential as a treatment of choroidal neovascularization that may minimize iatrogenic loss of vision.

Original languageEnglish (US)
Pages (from-to)2702-2710
Number of pages9
JournalInvestigative Ophthalmology and Visual Science
Volume38
Issue number13
StatePublished - Dec 1997

Keywords

  • Choriocapillary layer
  • Choroidal neovascularization
  • Laser
  • Occlusion
  • Photodynamic therapy

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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