Has anyone used the Keeler Fison, or the Topcon ID-5, B.I.O.? I understand the light from either is significantly different from that from a, say, Keeler Vantage or Heine Omega 500. Any opinions to this? Thanks much. *Title of thread ought to read, "Keeler Fison, Topcon B.I.O.s (Binocular Indirect Ophthalmoscope)."