All the references seem to spell it as you do. My guess is that it refers to any medical procedure which is performed by accessing the retina by going through the "vitreous humor" which fills the cavity behind the lens (of the eyeball.)

Mauro wrote: you can find some online here: http://pagina1.altervista.org/dictionaries_glossaries_gen.htm (all kinds). You can also download and use WordWeb or Wordnet for free (forever!) at http://wordweb.info/free/

Other dictionaries you might need: Merriam-Webster Online http://www.m-w.com/ Merriam-Webster provides a free online dictionary, thesaurus, audio pronunciations, Word of the Day, word games, and other English language resources.

I had worked for an ENT physician transcribing the dictation for five years. I have now gone to a different practice specializing in allergy, asthma, and sinus. Although, I am a great believer in "When in Rome, do as the Romans do," I find myself