Effects of indocyanine green injection on the retinal surface and into the subretinal space in rabbits.
OBJECTIVE
To evaluate the effects of indocyanine green (ICG) injection on the retinal surface and into the subretinal space of rabbit eyes.


METHODS
Twenty-two Dutch-belted rabbits underwent two-port vitrectomy followed by injection of ICG (5 mg/mL) on the retinal surface and into the subretinal space. Balanced salt solution (BSS) was also injected subretinally. The locations where ICG was delivered (both epiretinal and subretinal) were exposed to light from an endoilluminator for 7 minutes. The animals were examined at 1, 7, and 14 days after surgery. The eyes were studied by fluorescein angiography as well as light and electron microscopy.


RESULTS
No damage was observed after epiretinal ICG injection, but subretinal ICG injection resulted in damage to the outer nuclear layer, photoreceptor inner and outer segments, and retinal pigment epithelium. This damage was more severe with longer follow-up. Control experiments without ICG, in which balanced salt solution was injected into the subretinal space or light was delivered on the epiretinal surface, demonstrated only damage to the photoreceptor outer segments.


CONCLUSIONS
Subretinal delivery of ICG (5 mg/mL) in rabbits induces retinal pigment epithelium, photoreceptor inner and outer segment, and outer nuclear layer damage. These mechanisms of damage may explain the retinal pigment epithelium changes that are sometimes seen after ICG-assisted internal limiting membrane peeling in humans.
Maia
Mauricio
M
Wilmer Ophthalmological Institute, The Johns Hopkins University School of Medicine, 550 North Broadway, Baltimore, MD 21205, USA.
Kellner
Lukas
L
de Juan
Eugene
E
Smith
Ricardo
R
Farah
Michel E
ME
Margalit
Eyal
E
Lakhanpal
Rohit R
RR
Grebe
Lynnea
L
Au Eong
Kah-Guan
KG
Humayun
Mark S
MS
D000818:Animals; D004396:Coloring Agents / Q000633:toxicity*; D005110:Extracellular Space / Q000187:drug effects*; D005451:Fluorescein Angiography; D007208:Indocyanine Green / Q000633:toxicity*; D007267:Injections; D009457:Neuroglia / Q000187:drug effects / Q000648:ultrastructure; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects / Q000648:ultrastructure; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000648:ultrastructure; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000648:ultrastructure; D014821:Vitrectomy
D004396:Coloring Agents; D007208:Indocyanine Green