Abstract
Purpose :
Indocyanine green (ICG) is often used to assist in the visualization of the internal limiting membrane (ILM) and preretinal gliotic membranes during vitreoretinal surgery for macular hole repair and epiretinal membrane peel. Histopathologic studies of ILM remnants obtained during surgery suggest that ICG adheres to ILM, which represents a basal membrane produced by retinal Muller glial cells. In vitro studies have also shown that Muller glial cells can absorb ICG, and that exposure to ICG can lead to upregulation of grown factor receptors.
We identifed and describe a subset of eyes that underwent vitreoretinal surgery for macular repair and/or epiretinal membrane peel, and showed the presence of intraretinal inclusions visible with ICG angiography.
Methods :
Six eyes of 5 patients were studied using ICG angiography (Spectralis, Heidelberg) after vitreoretinal surgery for macular hole repair (4 eyes, 3 patients) and epiretinal macular membrane peel (2 eyes, 2 patients). ICG was used intraoperatively in all eyes. Two eyes (1 patient) had concomitant wet age-related macular degeneration (ARMD),1 eye (1 patient) had early dry ARMD, 2 eyes (2 patients) had mild non-proliferative diabetic retinopathy (NPDR), and 1 eye (1 patient) had severe NPDR with diabetic macular edema (DME). ICG angiograms of age-matched patients with similar surgical diagnoses without concomitant retinal disease were used for comparison.
Results :
Our group consisted of 3 females, 2 males, with a median age of 74. All eyes with concomitant retinal disease demonstrated the presence of punctate fluorescent inclusions in the retina visible with ICG angiography, not visualized with fluorescein angiography. These were more substantial in eyes with more severe retinal disease (wet ARMD and severe NPDR), and absent in eyes without concomitant retinal disease.
Conclusions :
The presence of fluorescent ICG inclusions in the retina after vitreoretinal surgery use suggests that ICG is actively assimilated by intraretinal cells, most likely Muller glial cells, during vitreoretinal surgery exposure. The fact that this is observed in patients with retinal disease suggests that this represents a physiologic marker of glial cell dysfunction.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.