Sudan staining of impression cytology retinal specimen

Abstract

Long-term silicone oil tamponade may cause increased numbers of vacuoles in the retina. Conventional methods of histological preparation dissolve silicone oil and optically empty spaces are seen. We examined the retinas of 20 human eyes after silicone oil injection. We obtained the material by peripheral retinectomies during vitrectomy for recurrent retinal detachment. The material was prepared by impression cytology. The time between silicone oil injection and vitrectomy was 3-18 months. The non-fixed cell sheets were stained with Sudan III, followed by a counterstaining with hematoxyline. Sudan III stained silicone oil 1000 mPa orange-yellow. Sudan-III-stained vacuoles in the retina were found in eight eyes with intraocular silicone oil instillation; in five of these eyes an emulsification of silicone oil was observed. The staining of retinal vacuoles seemed to be caused by the presence of silicone oil in the vacuoles. Using impression cytology and the Sudan staining procedure, it was possible to stain vacuoles in non-fixed retinal preparations. A long-term silicone oil tamponade induces these vacuoles in the retina, especially if the silicone oil is emulsified. In order to prevent this complication, removal of emulsified silicone oil should be performed as early as possible.