Abstract
Purpose :
Silicone oil endotamponades need to be injected and removed in a reasonable time and under moderate pressure conditions. However, due to ever decreasing sizes of incisions and trocars, injection and removal of highly viscous silicone oils is very time-consuming. To address resulting problems like longer treatment times or hypotonia, thixotropic silicone oils were developed. These oils are characterized by a diminished viscosity under constant mechanical stress: whilst there is pressure or vacuum acting on it, the oils will become more fluid and therefore much easier to be applied. Once the force it being removed from the oil, it will automatically return to its initial viscosity after a short period of time.
Methods :
The injection and removal times into enucleated pig eyes of three thixotropic silicone oils with a viscosity between 5000 and 9000cs were compared to standard silicone oils with viscosities of 1000cs, 2000cs and 5000cs respectively.
Results :
The injection times of all thixotropic silicone oils were reduced by more than 50% compared to standard silicone oils of corresponding viscosity. When the oil was removed from the eye, this benefit in terms of time efficiency was less distinct, but there still was a time reduction of approx. 30%.
Conclusions :
In small incision trocar-guided vitrectomy thixotropic silicone oils allow for a safe and time efficient injection of highly viscous silicone oil endotamponades. By the use of these thixotropic effects an ophthalmic surgeon could theoretically apply silicone oils of much higher viscosity than the ones being in use right now.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.