Abstract
Purpose: :
Perflurocarbon liquids are an important intraoperative tool in the management of complicated retinal detachment. Nevertheless, there remains a need for substances that can be left in the eye postsurgically. We have tested a novel medium density liquid – DFPE – a partially fluorinated 10–carbon material. Building on our experience with perfluoro–n–octane (Perfluoron) we designed this material such that its physical properties should be favorable for short term postoperative tamponade.
Methods: :
The vitreous in rabbits was compressed by an injection of 0.3–0.5 cc pure perfluoropropane (C3F8). After 3 days, the gas was replaced by liquid DFPE (8 rabbits) or saline (controls) (8 rabbits). After 1 or 3 months the DFPE liquid was removed and the control eyes underwent a sham–removal procedure. Dark–adapted corneal electroretinograms (ERGs) were obtained before surgery and after removal of the PFPD or saline. 3 rabbits were studied in both the dark and light–adapted state to separate cone and rod responses. Rabbits were studied clinically before injection of the fluids, 1 and 4 weeks after injection of the fluids, and at the time of ERG recording. Examination included both anterior and posterior segments. Lens changes and the residual presence of DFPE liquid post–removal were evaluated.
Results: :
After intravitreal placement of DFPE for 1–month exposure, 1 eye demonstrated mild DFPE dispersion and 3 DFPE–eyes and 2–control eyes developed mild cataract. After 3 months exposure, 4 DFPE–eyes showed fluid dispersion and all DFPE–eyes developed mild to moderate cataract. The scotopic a– and b–wave amplitudes in DFPE–injected rabbits were not different than the controls. Residual DFPE in the vitreal cavity after removal was reflected in a change in the falling phase of the suprathreshold scotopic mixed rod/cone b–wave. This feature of the ERG was reversed by removal of residual DFPE or in the absence of intervention, gradually disappeared after about 4 months. During the period when the waveform was altered, threshold rod b–waves were normal but the light adapted cone b–wave was delayed.
Conclusions: :
Extended term placement of DFPE in the rabbit vitreal cavity was associated with normal scotopic ERG a– and b–wave amplitudes although fluid dispersion and mild cataract formation occurred.
Keywords: vitreous substitutes • vitreoretinal surgery