Supplementary Material for: ‘Mini-Gauge’ Pars Plana Vitrectomy: ‘Inside-Out View’ with the GRIN Solid Rod Endoscope F.H.J.Koch K.P.Luloh P.Singh S.Scholtz M.Koss 2007 <i>Purpose:</i> To stimulate the discussion about ‘mini-gauge’ pars plana vitrectomy. <i>Methods:</i> Gradient index high-resolution endoscopy to analyze the 23- or 25-gauge access into the vitreous cavity. A total number of 66 pars plana interventions (almost 200 cannulas) were performed and recorded with the gradient index solid rod endoscope as well as through the microscope. <i>Results:</i> Five main ‘inside-out’ observations were made through the endoscope. Some very slight rotating movement of the trocar was required to achieve a safe cannula implantation. Rotating the cannula too much could result in some unwanted side effects. The major amount of vitreous incarceration occurs during the implantation of cannulas. Incarcerated vitreous causes significant anterior-posterior vitreous traction. Intraocular cleaning of the port with the suction cutter releases the anterior-posterior traction without increasing the postoperative rate and degree of hypotony. Side effects like bleeding of the wound are likely to occur due to any sort of manipulation to the outside of the sclerotomy (i.e. cotton tips) other than the essential replacement of the conjunctiva. <i>Discussion:</i> Surgeons who are considering the conversion to mini-gauge pars plana vitrectomy systems may be aided by endoscopic observations.