Endoscopic vitreoretinal surgery: principles, applications and new directions

Abstract

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.

High-Resolution Ex-Vivo Imaging of Retina with a Laptop-Based Portable Endoscope

“…The console provides a high-resolution camera, xenon-light-based illumination, interfaces for fiberoptic cables, video output, and a treatment laser if needed. [ 13 ] Although this design is very practical, its bulky base unit and high cost, just like the original computer, limit its practicality. Sometimes, the image resolution cannot meet the surgeon's needs.…”

Effects of Image Processing Using Honeycomb-Removal and Image-Sharpening Algorithms on Visibility of 27-Gauge Endoscopic Vitrectomy

“…Optimal visualization of intraocular structures is one of the most important and sometimes challenging aspects of vitreoretinal surgery. When compromised anterior segment transparency or inadequate pupillary dilatation restricts transpupillary observation of the posterior eye segment, an adjunctive skill set of endoscopic vitrectomies can be of help [ 1 , 2 ]. In addition, the endoscope can visualize the ciliary processes, pars plana, and anterior retina without scleral depression, facilitating surgery on these areas without causing peripheral lens aberration or alteration of the normal anatomy from scleral indentation/deformation that are commonly encountered during conventional vitrectomy.…”

Anatomical and Visual Outcome of Combined Phaco-Vitrectomy vs Vitrectomy Alone

“…1 Stereopsis, visual details of surgical field, depth of focus and visual field itself are key dependent points of pars plana vitrectomy, and thus the essential requirement for successful and complete Posterior segment surgery is clarity of the ocular media. 2 There are multiple limitations to this which include preexisting cataract that may limit visualization of the retina, the normal clear crystalline lens may limit the removal of peripheral vitreous and traction relieved, and thus it may be more difficult to identify and treat peripheral pathology in phakic eyes. 1 It is important to note that even if there was no visually significant cataract prior to vitrectomy, various studies and clinical experience has shown that these patients will ultimately develop visually significant cataract and will require cataract surgery in future.…”