Abstract
Purpose :
Vitrectomy as a standard procedure in ophthalmologic surgery requires measures for stabilizing the eye after the procedure e.g. by silicon oil or gas tamponade. Disadvantages of silicon oil are emulsification, increase of the eye pressure and the necessity of a second surgical procedure to remove the oil. Disadvantage of using gases are the requirement of a special head posture of the patient and lower parts of the retina cannot be treated accordingly. Here we tested the feasibility of a thermosensitive hydrogel that can be injected into the eye in liquid form at room temperature and becomes solid at body temperature in pig eyes after vitrectomy ex vivo.
Methods :
Pig eyes from a local provider were fixed on a polystyrene surface on top of a heat plate to assure a temperature of about 35°C in the eye. Using a Megatron vitrectomy system (Geuder, Heidelberg, Germany) pars plana vitrectomy was performed. After a subsequent air infusion, the hydrogel was injected through the infusion access (20G or 23G) at a room tpemperature of 22°C. After sewing up all access points the eyes were put inside a plastic bag into a water bad at 37°C for 2 to 20 hours and then opened subsequently for inspection.
Results :
When using pig eyes from a local slaughterhouse at about 6 to 30 hours after removal, a pars plana vitrectomy ex vivo could be easily executed. Due to non-existing suction forces of the RPE, retinal detachment could not be prevented in all eyes when removing the vitreous as complete as possible. Nevertheless, at a room temperatur of 22°C a complete filling with the hydrogel could be accomplished through the 20 G infusion access as well as through the 23 G infusion access. After opening the anterior chamber and removal of the lens a solid hydrogel globe at 37°C filling the posterior eye was detected. Contrary to silicon oil the solid hydrogel in the eye “sticks” to the surrounding tissues. Therefore, a complete hydrogel removal was not possible after opening the eye for inspection. The weight of the removed hydrogel was 1.6 ± 0.8 g (Mean±SD, N=5).
Conclusions :
It is possible filling completely the posterior eye chamber of pig eyes with a thermosensitive hydrogel tamponade at 22°C room temperature after performing pars plana vitrectomy ex vivo. At 37°C, the hydrogel tamponade forms a solid globe inside the eyes.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.