4D Microscope-Integrated OCT to Visualize Depth-Related Steps During Anterior Segment and External Eye Procedures

Abstract

Purpose : Several ophthalmic surgical procedures require accurate assessment of instrument depth, which can be challenging from a standard top-down view of the surgical field. Using live intraoperative 4D (3D across time) swept-source microscope-integrated optical coherence tomography (SS-MIOCT), we demonstrate direct visualization of depth-related steps in glaucoma, strabismus, and corneal surgeries.

Methods : Six subjects undergoing tube shunt placement, trabeculectomy, iStent placement, lateral rectus resection, Descemet’s stripping automated endothelial keratoplasty (DSAEK), and deep anterior lamellar keratoplasty (DALK) were consented under a Duke IRB approved protocol. A 100kHz SS-MIOCT system with a volume rate of 2Hz was used to visualize key depth related steps intraoperatively, in real-time.

Results : SS-MIOCT provided surgeons with live guidance and visualized scleral tunneling, tube shunt positioning in the anterior chamber (AC), and suturing during tube shunt placement; scleral flap creation, sclerotomy, and iridectomy during trabeculectomy; positioning of stent in area of Schlemm’s canal during iStent placement; needle depth during muscle and scleral passes during strabismus surgery; fluid between graft and native cornea during DSAEK; and needle depth in cornea prior to air injection during DALK. Select images are shown in Fig. 1.

Conclusions : Assessment of instrument depth in the AC, sclera, muscle, and cornea can be challenging during ophthalmic procedures, but is important in avoiding complications such as inadequate reductions in intraocular pressure due to suboptimal positioning of drainage devices, muscle slipping and scleral perforation during strabismus surgery, non-adherence of the donor and native corneas during DSAEK, and unsuccessful big-bubble formation during DALK. SS-MIOCT allows for visual guidance of depth-based steps in real-time, making it a valuable tool for ophthalmic surgeons.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

SS-MIOCT volumetric (left, with manual false coloring) and B-scan (right) pairs showing (A) tube (green arrows) during tube shunt placement and (B) needle (green arrow) depth in sclera during strabismus surgery.