27 Optical Coherence Tomography–Assisted Anterior-Segment Surgery


27 Optical Coherence Tomography–Assisted Anterior-Segment Surgery

Gabor B. Scharioth

Femtosecond laser–assisted cataract surgery has been used to create the main corneal incision, side-port incision, capsulorhexis, and precutting of the nucleus. 1 The aim of this technology is to increase precision. Incision size and shape become more predictable. Capsulorhexis size, shape, and centration reach previously unknown accuracy. 2 Initially, femtosecond laser technology was used without additional control with intraoperative optical coherence tomography (OCT). Today, all available femtosecond-assisted cataract machines take advantage of increased control using intraoperative OCT monitoring (Fig. 27.1).

Fig. 27.1 LensEx (Alcon, Inc., Irvine, CA) system for femtosecond laser–asissted cataract surgery. Note the monitor with online optical coherence tomography images of the cornea and anterior segment with crystalline lens before surgery.

27.1 Intraoperative OCT in Cataract Surgery

Future perspectives on the intraoperative use of OCT technology in cataract surgery (Fig. 27.2) could include continuous monitoring of the anterior-chamber depth or volume to prevent surge phenomenon. An automated posterior-capsule recognition modes could be used to prevent phaco-tip contact to the posterior capsule and capsular breaks, which would increase dramatically the safety of cataract surgery, as capsular breaks with vitreous loss are still the most common complication of phacoemulsification. 3 OCT-assisted grading of hardness of the crystalline lens with automated selection of machine settings could optimize applied energy and fluidics and increase the effectiveness and safety of cataract surgery. Intraoperative control of intraocular lens (IOL) position could help to prevent refractive surprises. Once capsular bag refilling becomes available, intraoperative OCT control could be an option.

Fig. 27.2 Intraoperative optical coherence tomography during phacoemulsification. Note the phaco tip in the main incision and the horizontal groove after initial sculpting. The scan direction is indicated in the right inferior corner; scan direction could be changed. OD, right eye.

Besides cataract surgery, OCT technology seems quite useful in other anterior-segment surgeries. 4 Mounting an OCT to a microscope makes it possible to create intraoperative images or videos. With future developments, high-speed OCT (swept-source technology) and three-dimensional (3-D) calculations could be used. If the images are mirrored into a head-up display into the surgeon’s microscope view, the surgeon is enabled to continue surgery while moving his or her attention from the surgical area. Furthermore, both hands remain free and able to continue bimanual surgery. As technology improves, OCT might be added to view areas (like the anterior-chamber angle) that were previously difficult to observe. Microscope-mounted OCTs (Zeiss Meditec, Oberkochen, Germany) have intraoperative settings that monitor images using 3-D anterior-segment OCT reconstruction of the anterior-chamber angle region (Tomey Corporation, Tokyo, Japan) (Fig. 27.3).

Fig. 27.3 Image of three-dimensional optical coherence tomography (OCT) reconstruction of the anterior-chamber angle region with anterior-segment OCT.

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Jun 13, 2020 | Posted by in OPHTHALMOLOGY | Comments Off on 27 Optical Coherence Tomography–Assisted Anterior-Segment Surgery
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