Indocyanine green angiography (ICGA) is preferred over fluorescein angiography in the evaluation of polypoidal choroidal vasculopathy primarily because indocyanine green:
- A Fluoresces in the near-infrared spectrum and remains bound to plasma proteins, staying within the choriocapillaris ✓
- B Is a smaller molecule that leaks freely from the choriocapillaris
- C Is excreted exclusively through the retina, giving higher contrast in outer retinal lesions
- D Has an excitation wavelength in the visible blue range, improving resolution of the RPE
Correct answer: A. Fluoresces in the near-infrared spectrum and remains bound to plasma proteins, staying within the choriocapillaris
Explanation
Indocyanine green is about 98 percent protein-bound, so it does not leak from fenestrated choriocapillaris the way free fluorescein does. Its peak absorption and emission lie in the near-infrared range (around 805 and 835 nm), which penetrates the RPE, xanthophyll and subretinal blood, making it ideal for imaging choroidal lesions such as polyps in PCV. Option B describes fluorescein behaviour, and option D describes fluorescein excitation, not ICG.
Reference: Kanski's Clinical Ophthalmology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.