Abstract
Abstract: :
Purpose: Silicone oil which escapes to the subretinal space during vitrectomy surgery is deleterious to retinal detachment repair and is difficult to evacuate, especially if detected in the post-operative period. We wished to evaluate the size of retinal hole at which silicone oil escapes to the subretinal space under different intraocular pressures. Methods: Fresh vitrectomized porcine retinas were immersed in BSS in water-tight chambers, and pressurized intra-vitreally from 0 to 100 mmHg compared to atmospheric pressure. Retinal holes of various sizes were induced at the level of the equator. Silicone oil 1000 cs/BSS exchange was then carried out until the hole was covered with silicone oil. For each of the hole sizes, the pressure at which silicone oil egressed to the subretinal space was noted. Results: At hole diameter size 500um, silicone oil readily egressed to the subretinal space at open atmospheric pressure (IOP=0 mmHg). At progressively larger hole sizes, speed of silicone oil egress was proportionally increased without any application of induced infusion IOP. Mild manipulation of the globe greatly exacerbated silicone oil seepage through the retinal holes. Conclusion: Unlike intraocular gases or perflurocarbon liquids, silicone oil has virtually no tamponade effect directly on the retinal hole, and escapes to the subretinal space through any hole size at any infusion IOP. According to the preliminary data outlined above, silicone oil should never be instilled until the retina is completely flat. None. Silikon 1000 silicone oil donated by Alcon/Infinitech Surgical Division.
Keywords: 628 vitreoretinal surgery • 630 vitreous substitutes • 563 retinal detachment