Tamponade properties of double-filling with perfluorohexyloctane and silicone oil in a model eye chamber

Background: The use of perfluoroexyloctane as a heavier-than-water tamponade for long-term use is limited by its tendency to dispersion and associated intraocular inflammation. Double-filling with silicone oil and F6H8 produces a united, two-layer bubble, appearing as a single bubble. This has been proposed as a method of improving the utility of F6H8 as a tamponade. Methods: A surface modified polymethylmethacrylate model eye chamber was double-filled with perfluorohexyloctane and silicone oil to approximate a 90% fill. The proportion of silicone oil was increased in a stepwise fashion. A qualitative comparison of surface contact at each stage was made. Chambers with one, two or no indent were used. Dispersion by agitation of the chamber was assessed. Results: With less than 20% silicone oil it was difficult to force the two liquids to make contact. With more oil they united in the form of a single bubble joined at an interface. Once joined, the sides of the single bubble were drawn away from the wall of the chamber. As the proportion of silicone oil increased the area of lost contact increased and progressed inferiorly. Compared to F6H8 alone the double-fill reduced dispersion. Conclusion: Silicone oil and F6H8 can unite to form a single bubble that changes the effectiveness of either tamponade agent on their own. The double-fill needs to have enough silicone oil to form a single bubble, but this needs to be kept as low as possible to avoid progressive loss of lateral tamponade. It does not provide good simultaneous superior and inferior tamponade. The double-fill reduces dispersion. © Springer-Verlag 2003.link_to_subscribed_fulltex

Tamponade efficiency of perfluorohexyloctane and silicone oil solutions in a model eye chamber

Background/aim: As no single tamponade agent yet fulfils all the requirements of a long term inferior tamponade, attempts have been made to mix tamponade materials. This study investigated perfluorohexyloctane (F(6)H(8)) and silicone oil solutions designed to take advantage of the high specific gravity and interfacial tension of the F(6)H(8) and the high viscosity of silicone oil. Methods: Solutions of three different densities were examined (1.01, 1.03 and 1.06 g/cm(3)) inside transparent chambers made of surface modified poly(methylmethacrylate) (PMMA). Results: Compared to F(6)H(8), the solutions had poorer contact with hydrophilic surface of the chambers. The higher the specific gravity of the solution, the better was the contact. The solution with a specific gravity 1.01 g/cm(3) is probably of no use clinically. Conclusion: The model eye chamber made of surface modified PMMA is an efficient way of screening and choosing solutions with promising physical properties. Solutions of silicone oil with F(6)H(8) in other proportions or with other semifluorinated alkanes may be of interest

Heavy tamponade 2 Densiron 68® in routine clinical practice: Anatomical and functional outcomes of a consecutive case series

Purpose: To evaluate the safety and efficacy of Densiron 68® in the clinical management of complex vitreoretinal cases with inferior retinal pathology. Methods: We present a prospective interventional non-comparative case series of 122 eyes of 121 consecutive patients. The primary end point was anatomical re-attachment of the retina, defined as retinal re-attachment in the absence of any tamponade agent. The secondary end point was to record the visual function and surgical complications. Inclusion criteria were proliferative vitreoretinopathy, posterior or inferior retinal breaks, and the patient's inability to posture. Results: Patients were 59.9 years (±19.6), (m/f=72:49), (R/L=65:57). Seventy-seven (63.1%) had previous unsuccessful retinal surgery and 45 had Densiron 68 at first procedure. The extent of the detachments was 2.21 quadrants (±1.07) with macular involvement in 66 cases (54%). Eighty-seven (71.3%) patients achieved retinal re-attachment with one retinal operation and ultimately no tamponade, 102 (83.6%) achieved retinal re-attachment with more than one operation and ultimately no tamponade, and 112 (91.3%) patients achieved flat retina with tamponade in situ. Visual acuity rose from 1.38 LogMar (±0.87) to 1.06 (±0.83) (P=0.007). Densiron was removed after 135 days (±73.2; range 35-405). Conclusion: No tamponade agent can provide simultaneous support for the superior as well as the inferior retina; therefore, a tamponade agent that 'sinks' is a welcome new tool at the surgeon's disposal. The sequential use of heavy silicone oil followed by conventional silicone oil may be an acceptable management strategy in recurrent detachment.link_to_subscribed_fulltex

Heavier-than-Water Silicone Oil Mixture as a Long-Term Tamponade Agent: A Pilot Study

Purpose: To evaluate the tamponade effect on the retina of a heavier-than-water silicone oil mixture and to compare it with the effect of silicone oil. Methods: Prospective, non-randomised, comparative pilot study. Phakic/pseudophakic patients with retinal detachment undergoing vitrectomy with Densiron 68 or silicone oil were recruited. The 'separation volume', defined as the relative volume of the space between intraocular tamponade agent and retina, was estimated using magnetic resonance imaging in both groups and compared. Results: Nine participants were included; 4 received silicone oil and 5 Densiron 68. The mean separation volume was statistically significantly larger in the silicone oil group (0.477 ± 0.419 cm ) than in the Densiron group (0.042 ± 0.013 cm ; p = 0.014). Conclusions: In this study Densiron achieved an excellent tamponade effect in the retina