Cytotoxicity of indocyanine green on retinal pigment epithelium: implications for macular hole surgery

Arch Ophthalmol. 2003 Oct;121(10):1423-9. doi: 10.1001/archopht.121.10.1423.


Objective: To evaluate the potential cytotoxic effects of indocyanine green (ICG) on cultured human retinal pigment epithelium (RPE) and the resultant implications for macular hole surgery.

Methods: Human RPE cells were exposed to ICG in concentrations from 0.001 to 5 mg/mL. The exposure duration ranged from 5 minutes to 3 hours. Light microscopy, MTS viability assay, and calcein AM-ethidium homodimer 1 staining were used to evaluate the cytotoxic effects of ICG.

Results: The RPE cells incubated with up to 5 mg/mL of ICG for 5 minutes or less exhibited no morphologic change and no significant decrease in dehydrogenase activity. When RPE cells were exposed to 5 mg/mL of ICG for 10 minutes, 1 mg/mL of ICG for 20 minutes, or 0.01 mg/mL of ICG for 3 hours, cell morphologic features were altered, mitochondrial dehydrogenase activity decreased, and some cells were necrotic.

Conclusions: Indocyanine green caused cytotoxicity in cultured human RPE in a dose- and time-dependent manner. Cell death occurred by necrosis.

Clinical relevance: Exposure of RPE cells to ICG concentrations up to 5 mg/mL for 5 minutes or less was not injurious; prolonged exposure to a low ICG concentration was toxic. Since ICG may be retained in the vitreous cavity for a lengthy period, thorough washout of ICG during macular hole surgery is required.

MeSH terms

  • Cell Death
  • Cells, Cultured
  • Coloring Agents / toxicity*
  • Dose-Response Relationship, Drug
  • Ethidium / analogs & derivatives*
  • Fluoresceins
  • Humans
  • Indocyanine Green / toxicity*
  • Mitochondria / drug effects
  • Mitochondria / enzymology
  • Necrosis
  • Oxidoreductases / metabolism
  • Pigment Epithelium of Eye / drug effects*
  • Pigment Epithelium of Eye / metabolism
  • Pigment Epithelium of Eye / pathology
  • Retinal Perforations / surgery
  • Time Factors


  • Coloring Agents
  • Fluoresceins
  • calcein AM
  • ethidium homodimer
  • Oxidoreductases
  • Ethidium
  • Indocyanine Green