Abstract
Abstract: :
Purpose: Perfluorocarbon liquids and heavy fluorocarbon liquids are useful in vitreoretinal surgery but have to be removed at the completion of the surgery since long term intraocular tolerance is still unsatisfactory. Long term tolerance to perfluorohexylhexane liquid (F6H6) was tested in the rabbit eye. Methods: 16 rabbits were tested. The vitreous gel was first compressed by an injection of 0.3–0.5cc pure perfluoropropane (C3F8) gas into the vitreal cavity. 3 days later, the gas was replaced by liquid F6H6 (test rabbits) or saline (controls). The rabbits were divided into two groups: group 1– F6H6 (4 rabbits) or saline (4 rabbits) were injected into the vitreal cavity. 1 month post injection the F6H6 or saline was removed and replaced with saline. Group 2– F6H6 (4 rabbits) or saline (4 rabbits) were injected into the vitreal cavity. 3 months post injection the F6H6 or saline were removed and replaced with saline. Scotopic electroretinogram (SERG) recordings were performed pre–surgery and post removal of the fluids (F6H6 or saline). Clinical examination was performed pre injection of the fluids, 1 week (groups 1 and 2) and 4 weeks (group 2) post injection of the fluids, and at the time of SERG recording and included lens and retinal evaluation. The presence of intravitreal cells, cataract formation, and dispersion of the F6H6 was also noted. Results: Group 1– mild vitreal inflammation was noted in 2 eyes. 1 eye developed cataract. All eyes developed mild to moderate F6H6 dispersion. Mean a– and b–wave amplitudes were not significantly reduced post removal of the F6H6 in the study eyes compared to the pre surgery amplitudes and compared to the control group (2 tail student T–test; a–wave P=0.179 and P=0.392 respectively, b–wave P=0.064 and P=0.483 respectively). B–wave implicit times were not affected. Group 2– severe vitreal inflammation and cataract were noted in 3 eyes injected with F6H6. 1 eye developed mild vitreal inflammation. The 3 eyes with vitreal inflammation and cataract developed total retinal detachment post removal of the fluid; mean a– and b–wave amplitudes, and implicit times were severely reduced post surgery. In 1 eye no change in mean a– and b–wave amplitudes were noted post removal of the F6H6 compared to pre–operative values. Conclusions: F6H6 causes ocular inflammation and cataract formation which increases over time. The SERG responses are not significantly affected when the F6H6 is left in the vitreal cavity for 1 month.
Keywords: vitreous substitutes • vitreoretinal surgery • retinal detachment