Throughout history, different intraocular illumination methods for vitreoretinal surgery have been used and the most common limitations to the state-of-the-art intraocular illumination methods are the glare and reflections created by the illumination device and the relatively small illuminated area. A way to tackle these limitations could be by using a ring-light configuration, which produces diffuse scattered illumination for a full 360° around the object. In this study, we developed and experimentally evaluated two ring-light configurations for intraocular illumination during vitreoretinal surgery: one for insertion through the pars plana (20 mm), and one for insertion through the cornea and placement in the posterior chamber (11 mm). Both prototypes are made from a 27 gauge Eckardt TwinLight (DORC, the Netherlands), placed inside a capillary tube cut in half through the length. Cuts were made in the fiber every 2 mm, perpendicular to the length of the fiber, to allow light to exit the fiber through the cladding. By measuring the light intensity and illuminated area, we found that the ring-light configurations produce a lower light intensity but also a slightly larger illuminated area and a more diffuse and uniformly distributed illumination than the Eckardt TwinLight. The placement of the ring-light in the posterior chamber proved to be unsafe and complex, since the installation procedure in ex-vivo porcine cadaver eyes could not be executed without damaging the lens bag, lens zonules, posterior iris and cornea, due to the lack of space in the posterior chamber, and the rigidity and sharp tip of the ring. The ring-light configuration that is inserted through the pars plana also caused damage to the retina and lens bag, due to the ring’s rigidity and its sharp tip. However, this configuration shows potential when the ring would be made from a more flexible material and has an incorporated pigtail curve a the distal end, which can be easily achieved in a future version of the prototype.

Retinal detachment occurs when liquid slips behind the retina and does not allow the latter to lay flat on the posterior region of the eye. It alters the vision of the patient, hence requiring surgery to be corrected. In some cases, retinal detachment can occur after the retina has been treated for other pathologies. Indeed, more than 20% of highly myopic patients who have been treated for retinal diseases are subject to retinal detachment a few months after the surgery and are required to undergo a second surgery. It is believed that a membrane, also called Vitreous Cortex Remnants (VCR), that arises due to vitreoschisis, a retinal disease, is the reason for the re-detachment. VCR is often not dealt with during surgery because its removal is time-costly, the VCR is not well visible and instruments are not optimally adapted for removing VCR. The work aims to develop and experimentally evaluate new methods of removing VCR. For that purpose, a series of test prototypes were manufactured, and three surgeons assessed the efficiency of the prototypes for removing VCR from dissected pig’s eyes. Each eye was treated pre-experimentally according to a new model that tries to recreate vitreoschisis in a young porcine eye. The efficiency of each test prototype was assessed based on the force that the instrument tip exerted on the pig’s retina, the number of strokes taken to remove the VCR completely, the tissue damage and the time used. Furthermore, the optimal tip length was determined based on the surgeons’ feedback. The results show that the force greatly depended on the stiffness of the instrument tip and that the most efficient prototype consisted of a PVA wipe cut to size 6x1x1 mm and a 0.1 mm diameter Nitinol wire. The prototype exerted a maximum force of 0.68 gr. The number of strokes was around 40, and the optimal tip length was just under 4.5 mm. While the experiments showed that it is a promising design, the tip needs to be remodeled to comply with the low stiffness needed and to be able to fit within a 23 gauge tube.