title: Experimental selective choriocapillaris photothrombosis using a modified indocyanine green formulation.
abstract: BACKGROUND
  This in vivo study assessed and compared the effectiveness of an aqueous indocyanine green (ICG) formulation (R-ICG) and a lipid ICG formulation (L-ICG) in occluding the rabbit choriocapillaris, and determined the singlet oxygen quantum yields and aggregation properties of both formulations in vitro.
  
  
  METHODS
  Singlet oxygen production and aggregation were compared. The eye fundus of 30 albino rabbits was irradiated 0-15 min after dye injection using an 810 nm diode laser. Fluorescein angiography and light microscopy were used to evaluate the safety and efficacy of R-ICG and L-ICG.
  
  
  RESULTS
  L-ICG decreased the dimerisation constant and the tendency of ICG to form aggregates, and increased the efficiency of ICG in generating singlet oxygen (R-ICG, PhiDelta = 0.120 and L-ICG, PhiDelta = 0.210). Using a 10 mg/kg dose, choriocapillaris occlusion was achieved at a light dose of 35.8 J/cm(2) with L-ICG and 71.6 J/cm(2) with R-ICG with minimal damage to the neurosensory retina.
  
  
  CONCLUSIONS
  Restrictions to the use of ICG in aqueous solution, low singlet oxygen quantum yields and high aggregation tendency, were overcome with L-ICG. The lower laser irradiance required to obtain choriocapillaris occlusion may suggest that L-ICG is a more potent and selective photosensitiser than R-ICG.
authors.affiliation: Hospital de Olhos de Araraquara, R: Henrique Dall'Aqua, 45. Araraquara-SP, Brazil. hospitaldeolhos@uol.com.br
authors.forename: J A
authors.initials: JA
authors.lastname: Cardillo
authors.forename: R
authors.initials: R
authors.lastname: Jorge
authors.forename: R A
authors.initials: RA
authors.lastname: Costa
authors.forename: S M T
authors.initials: SM
authors.lastname: Nunes
authors.forename: D
authors.initials: D
authors.lastname: Lavinsky
authors.forename: B D
authors.initials: BD
authors.lastname: Kuppermann
authors.forename: A C
authors.initials: AC
authors.lastname: Tedesco
authors.forename: M E
authors.initials: ME
authors.lastname: Farah
mesh_terms: D000818:Animals; D002196:Capillaries / Q000187:drug effects / Q000528:radiation effects; D002626:Chemistry, Pharmaceutical; D002829:Choroid / Q000098:blood supply*; D007208:Indocyanine Green / Q000627:therapeutic use*; D007834:Lasers; D055095:Optics and Photonics; D010100:Oxygen / Q000737:chemistry; D010777:Photochemistry; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011817:Rabbits
chemical_list: D017319:Photosensitizing Agents; D007208:Indocyanine Green; D010100:Oxygen