Purpose: To investigate the possible persistence and characteristics of infrared fluorescence of the fundus for several months after surgery with intraocular injection of indocyanine green (ICG).
Design: Interventional, noncomparative, prospective case series.
Participants: Seventeen patients operated on in our department with ICG injection into the vitreous cavity, who gave prior informed consent.
Methods: After standard three-port pars plana vitrectomy and posterior vitreous detachment, 0.1 to 0.2 ml of an ICG solution at a concentration of 2.5 mg/ml was injected through a 5- micro m sterile filter over the posterior pole and left in place for 3 minutes. The stained internal limiting membrane was then peeled off. Patients had postoperative infrared fundus photographs at each consultation in our department. Follow-up ranged from 1 to 7 months. Visual acuity and any unexpected event were also recorded.
Main outcome measures: Postoperative infrared fluorescence of the fundus.
Results: The day after surgery, no green ICG staining of the fundus was visible on biomicroscopy. However, infrared photography showed diffuse fluorescence of the fundus. At 1 and 3 postoperative months, infrared fundus photography showed an intensely fluorescent optic nerve disc. In patients with macular hole, the center of the macula also exhibited faint granular fluorescence. At 6 months postoperative or later, only the optic disc remained fluorescent, but the fluorescence was far less intense than at 3 months. Infrared photographs of the fellow eyes exhibited no fluorescence. Visual acuity improved or was unchanged compared with preoperative vision in 16 eyes and decreased by 1 line in 1 eye.
Conclusions: After intraoperative use of ICG for macular surgery, fluorescence of the optic disc and of the macular center after macular hole surgery persisted for months in all cases. ICG may accumulate in the macular pigment epithelium and optic nerve, raising the problem of the as yet unknown pharmacokinetics of ICG after intravitreous administration and of its long-term safety.