We read with great interest the article “Ability of New Vital Dyes to Stain Intraocular Membranes and Tissues in Ocular Surgery,” by Rodrigues and associates. We congratulate the authors for an excellent article highlighting various novel vital dyes that can be used to stain intraocular membranes.
The authors rightly pointed out the growing concern over the use of trypan blue and indocyanine green and included other possible dyes in their study. We believe, in addition to various dyes used, sodium fluorescein also could have been compared for staining the vitreous. The study mainly concentrates on the staining ability of the dyes and on the morphologic toxic effects. Histopathologic changes in the retina of enucleated eyes have been reported by Grisanti and associates. Comparing these histologic changes after enucleation with those that have occurred after staining of dyes could have established a better understanding of the toxicity of the dyes used. We would like to add that the removal of vitreous by cotton bud and forceps by itself may cause retinal tissue disorganization. Authors have reported absence of hemorrhage, inflammation, or detachment in porcine retinal specimens. We believe that inflammation cannot be a marker for toxicity in a retinal tissue after enucleation. The method used for grading of the staining was subjective. A computer software-based method might have given more objective results. The staining of human epiretinal membrane was carried out with all 16 dyes, but results for only 9 dyes were reported. Indocyanine green was considered to be a safe dye; however, its toxicity to the retina is well known. This study has established the staining ability of the newer dyes, but further information regarding the safety of the dyes is needed by conducting effects on cell culture models and in vivo experimentation.