Design and realisation of drop-free trocar for ophthalmic applications

In this work a novel patented drop-free trocar (Italian Patent PI2007A000021) is described for minimum- invasive ophthalmic surgery. In this surgical practice the trocar has the function of microchannel for the insertion of surgical instruments into the vitreous cavity. The drop pressure between the inner cavity of the eye and the external environment causes the formation of a drop of vitreous humour at trocar-external environment interface. The outflow of vitreous humour produces a high risk of infection. This problem can be reduced by removing the amount of vitreous humour inside the cannula; but its reduction in the vitreous cavity is one of the principal risk factor of retinal detachment. For this reason the ophthalmic surgeons needs to have a device for minimum-invasive that allows to reduce the risks avoiding the outflow of vitreous humour. We have modelled, designed and realised a self-sealing valve system to prevent this flow through the cannula. This device is able to reduce retinal detachment risk or infections allowing safe minimum-invasive ophthalmic surgery. In this paper we describe the development and the first experimental results of this novel patented trocar.