Electrophysiological responses after vitrectomy and intraocular tamponade.

Earlier reports of changes in the electroretinogram (ERG) following intravitreal liquid silicone in animal eyes have been conflicting. There is little information on the effects of vitrectomy and intravitreal tamponade by gas or liquid silicone on retinal function in humans. The effects on retinal function of intraocular tamponade by liquid silicone (1,000 cs) or SF6 gas (20 per cent)/mixture were studied in a series of consecutive patients undergoing vitrectomy for recent rhegmatogenous retinal detachment. Patients without retinal detachment requiring vitrectomy served as controls. Serial electroretinography was performed immediately preoperatively, postoperatively and subsequently over a period of 6 months. In the early postoperative period there was a reduction of both a- and b-waves through these recovered progressively in all the patients. The recovery of the ERG was accelerated by the absorption of the gas or by the removal of the liquid silicone. The results of our study indicate that the initial depression of the ERG is due to vitrectomy and subsequent recovery occurs even in the presence of intraocular gas or liquid silicone. It is suggested that the relative reduction of the amplitude of a- and b-waves in the study patients is due to the insulating effect of the tamponading agent and that neither intraocular gas nor liquid silicone adversely affects retinal function.