Clinical evaluation and feasibility of changing intraoperative visibility with a novel viewing filter system for human eye

Endoscopic vitreoretinal surgery: principles, applications and new directions

Purpose

To analyze endoscopic vitreoretinal surgery principles, applications, challenges and potential technological advances.

Background

Microendoscopic imaging permits vitreoretinal surgery for tissues that are not visible using operating microscopy ophthalmoscopy. Evolving instrumentation may overcome some limitations of current endoscopic technology.

Analysis

Transfer of the fine detail in endoscopic vitreoretinal images to extraocular video cameras is constrained currently by the caliber limitations of intraocular probes in ophthalmic surgery. Gradient index and Hopkins rod lenses provide high resolution ophthalmoscopy but restrict surgical manipulation. Fiberoptic coherent image guides offer surgical maneuverability but reduce imaging resolution. Coaxial endoscopic illumination can highlight delicate vitreoretinal structures difficult to image in chandelier or endoilluminator diffuse, side-scattered lighting. Microendoscopy’s ultra-high magnification video monitor images can reveal microscopic tissue details blurred partly by ocular media aberrations in contemporary surgical microscope ophthalmoscopy, thereby providing a lower resolution, invasive alternative to confocal fundus imaging. Endoscopic surgery is particularly useful when ocular media opacities or small pupils restrict or prevent transpupillary ophthalmoscopy. It has a growing spectrum of surgical uses that include the management of proliferative vitreoretinopathy and epiretinal membranes as well as the implantation of posterior chamber intraocular lenses and electrode arrays for intraretinal stimulation in retinitis pigmentosa. Microendoscopy’s range of applications will continue to grow with technological developments that include video microchip sensors, stereoscopic visualization, chromovitrectomy, digital image enhancement and operating room heads-up displays.

Conclusion

Microendoscopy is a robust platform for vitreoretinal surgery. Continuing clinical and technological innovation will help integrate it into the modern ophthalmic operating room of interconnected surgical microscopy, microendoscopy, vitrectomy machine and heads-up display instrumentation.

Rugate filters used in slit-lamp delivery to improve color rendering of illumination for retinal photocoagulation

Laser filters and color filters used in slit-lamp delivery have been developed by the rugate approach to improve color rendering of illumination for retinal photocoagulation. The double-notch laser filter is designed according to the required laser lines and incident angle. Based on the transmission spectrum of a double-notch laser filter and the spectral power distribution (SPD) of the light source of a slit lamp, a scanning search algorithm is applied to find the optimal transmission spectrum of a multi-notch color filter for the best color rendering index of illumination. Open-source software is used to design the refractive index profile of the rugate filters, which are deposited by the reactive pulse magnetron sputtering. Both the theoretical analysis of SPD of slitlamp delivery with consideration of the deposited rugate filters and the experimental results demonstrate that the color rendering property of illumination can be improved remarkably, thus making fundus observation and retinal laser photocoagulation more reliable and efficient.