Morphologic and clinical effects of subretinal injection of indocyanine green and infracyanine green in rabbits.
OBJECTIVE
The aim of this study was to determine the effects of subretinal injection of indocyanine green (ICG), infracyanine (IfCG), and balanced salt solution (BSS) in rabbits.


METHODS
Ten (10) animals were subjected to a subretinal injection of 0.05% ICG (279 mOsm), 0.5% IfCG (276 mOsm), and BSS (300 mOsm) used as a control. Animals were examined at 6, 12, and 24 h and 14 days following the surgical procedure by indirect binocular ophthalmoscopy, fluorescein angiography (FA), and light and transmission electron microscopy.


RESULTS
The subretinal injection of ICG caused damage to all retinal layers and retinal pigment epithelium (RPE) during the entire follow-up. Subretinal injection of IfCG resulted in abnormalities of the photoreceptor outer segments (POSs) during the entire follow-up; however, abnormalities of the photoreceptor inner segments (PISs) and outer nuclear layer (ONL) were observed only 24 h and 14 days after surgery; no RPE damage was observed. FA showed that window defects were more prominent in the subretinal ICG bleb position than the IfCG-related area. BSS caused only abnormalities of the POS layer and no RPE alterations.


CONCLUSIONS
Subretinal injection of 0.05% ICG results in more significant retinal damage than 0.5% IfCG. In this model, iodine-free IfCG demonstrates a safer profile than a tenfold lower concentration of ICG, which contains iodine in its composition.
Penha
Fernando M
FM
Department of Ophthalmology, Vision Institute (IPEPO), Federal University of São Paulo, São Paulo, Brazil.
Maia
Maurício
M
Farah
Michel E
ME
Dib
Eduardo
E
Príncipe
André H
AH
Devin
Fracois
F
Rodrigues
Eduardo B
EB
Duprat
João P
JP
Freymüller
Edna
E
D000818:Animals; D004396:Coloring Agents / Q000008:administration & dosage / Q000633:toxicity*; D004596:Electroretinography; D005500:Follow-Up Studies; D007208:Indocyanine Green / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000633:toxicity*; D007267:Injections; D046529:Microscopy, Electron, Transmission; D009994:Osmolar Concentration; D019999:Pharmaceutical Solutions; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000473:pathology
D004396:Coloring Agents; C116320:Infracyanine green; D019999:Pharmaceutical Solutions; D007208:Indocyanine Green