BR
B. Riemens
info
Please Note
<p>This page displays the records of the person named above and is not linked to a unique person identifier. This record may need to be merged to a profile.</p>
2 records found
1
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. ...
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. ...
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.
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.
Battery Free Jogger Light
Energy Storage
The deliverable of this project is a light for joggers that does not use a battery and keeps blinking for a short period of time after standing still. This research details the design and implementation of the storage part of a battery free jogger's light. The goal of this storage part is that it stores energy delivered by an energy harvester so that it can power LEDs for at least 30 seconds when there is no energy harvested anymore. The system consists of a full-bridge rectifier, a voltage regulator, a supercapacitor to store the energy and a switch to couple or decouple the load. The main trade-off of this research is between the charging and discharging times of the supercapacitor. Results show that LEDs in the rectifier offer advantages, since there is instant lighting when jogging and which makes the charging time less critical. With this feature the discharging time could be increased up to one minute. The total efficiency of this storage system is calculated to be 67.9\%.
...
The deliverable of this project is a light for joggers that does not use a battery and keeps blinking for a short period of time after standing still. This research details the design and implementation of the storage part of a battery free jogger's light. The goal of this storage part is that it stores energy delivered by an energy harvester so that it can power LEDs for at least 30 seconds when there is no energy harvested anymore. The system consists of a full-bridge rectifier, a voltage regulator, a supercapacitor to store the energy and a switch to couple or decouple the load. The main trade-off of this research is between the charging and discharging times of the supercapacitor. Results show that LEDs in the rectifier offer advantages, since there is instant lighting when jogging and which makes the charging time less critical. With this feature the discharging time could be increased up to one minute. The total efficiency of this storage system is calculated to be 67.9\%.