Toxicity of indocyanine green injected into the subretinal space: subretinal toxicity of indocyanine green.
OBJECTIVE
To evaluate the toxicity of indocyanine green (ICG) injected into the subretinal space. Indocyanine green may come in contact with photoreceptors and retinal pigment epithelium through a macular hole during ICG-assisted peeling of the internal limiting membrane.


METHODS
Balanced salt solution or ICG of various concentrations (0.6, 1.25, 2.5, or 5.0 mg/mL) was injected into the subretinal space of rabbit eyes and removed after 1 minute. After 3 days, 1 week, and 4 weeks, the eyes were enucleated and evaluated by light microscopy and electron microscopy.


RESULTS
When the ICG of 1.25 mg/mL or higher concentration was injected into the subretinal space, degenerative changes of the photoreceptors and the retinal pigment epithelial cells were found after 3 days with light and electron microscopy. After 1 week, the outer retina was disintegrated and the photoreceptors were not found. After 4 weeks in the eyes with 1.25 mg/mL ICG, short photoreceptors and a thin outer nuclear layer were seen. In the eyes with 2.5 mg/mL or higher ICG, the photoreceptors and the outer nuclear layer were destroyed completely.


CONCLUSIONS
The results of this study suggest that the ICG of 1.25 mg/mL or higher concentration has toxicity to the outer retina of the rabbit and may cause adverse effects on the functional outcome after macular hole surgery.
Department of Ophthalmology, School of Medicine, University of Miami, Bascom Palmer Eye Institute, Miami, Florida 33136, USA. lorenzo-lee@hanmail.net
Ji Eun
JE
Lee
Tae Jin
TJ
Yoon
Boo Sup
BS
Oum
Jong Soo
JS
Lee
Hee Young
HY
Choi
D000818:Animals; D004396:Coloring Agents / Q000008:administration & dosage / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D007208:Indocyanine Green / Q000008:administration & dosage / Q000633:toxicity*; D007267:Injections; D009887:Ophthalmoscopy; D010786:Photoreceptor Cells / Q000187:drug effects / Q000648:ultrastructure; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000648:ultrastructure; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000648:ultrastructure
D004396:Coloring Agents; D007208:Indocyanine Green