Abstract
Abstract: :
Purpose: To investigate the characteristics of the persistence of infrared (IR) fluorescence of the fundus after intraocular injection of indocyanine green (ICG). Methods: 0.2 ml of an ICG solution at a concentration of 2.5 mg/ml was injected over the posterior pole of 17 patients operated on for macular hole (MH) or epiretinal membrane (ERM). The stained internal limiting membrane (ILM) was then peeled off. Patients had post-operative IR fundus photographs at each subsequent consultation. The follow up period ranged from 1 to 7 months. Experiments were also performed on rabbits: 250 micrograms of the same ICG solution was injected into the vitreous of one eye of rabbits and the other eye served as control. Rabbits were sacrificed 3 weeks later. Their eyes were enucleated and IR photographs of the fundus and optic nerves were taken. Results: In human eyes, IR photography on the day after surgery, showed diffuse fluorescence of the fundus, even in the area of ILM removal. At 1 and 3 postoperative months, IR fundus photography showed an intensely fluorescent optic nerve disk in all cases. In cases of MH, the center of the macula also exhibited fluorescence. At 6 postoperative months or later, only the optic disk remained fluorescent in all cases, but far less intensely than previously. Visual acuity improved or was unchanged in 16 eyes, and decreased by 1 line in 1 eye. In rabbits, IR photographs of the fundus showed intense fluorescence of the visual streak area. After sagittal section of the eye and optic nerve, IR photographs showed intense fluorescence of the optic nerve behind the eye, even beyond the optic chiasma. No fluorescence was detected in the control eye or the controlateral optic nerve. Conclusion: After peroperative use of ICG, fluorescence persisted for at least 7 months in center of the macula in cases of MH, and in the optic disk in all cases. In rabbits, ICG seemed to migrate into the optic nerve. This may explain the persistent fluorescence of the optic disk in the patients, and raises the problem of the long-term safety of intraocular injection of ICG.
Keywords: 554 retina • 498 optic disc • 567 retinal pigment epithelium