Vital dyes for macular surgery: a comparative electron microscopy study of the internal limiting membrane

To analyze and compare the ultrastructure of the retinal cleavage plane of the internal limiting membrane (ILM) removed during dye-assisted macular surgery.

Ninety-six surgical specimens of the ILM obtained during trypan blue (TB)-, brilliant blue G (BBG)-, bromphenol blue (BPB)-, Chicago blue (CB)-, and indocyanine green-assisted pars plana vitrectomy for idiopathic macular hole and macular pucker were evaluated using transmission electron microscopy. Specimens removed without dye assistance served as controls.

Specimens removed after TB-, BBG-, BPB-, and CB-staining presented with significantly less cellular fragments (in size and quantity) at the retinal side of the ILM than specimens after indocyanine green staining. Large cellular fragments and Müller cell endfeet, which were typically present after indocyanine green staining, were not found after TB, BBG, BPB, and CB staining. Comparing all groups, TB was found with less retinal debris than BBG, BPB, and CB. Specimens removed without intravitreal dye administration showed the least retinal fragments that were solitarily distributed at the ILM.

Trypan blue, BBG, BPB, and CB cause significantly less morphologic changes at the retinal cleavage plane than indocyanine green. Further studies are required to elucidate if presence and amount of retinal cell fragments at ILM specimens correlate with functional deficits.