Real-time intraoperative assessment of the cornea with microscope integrated optical coherence tomography

Abstract

 

Purpose

 

To explore microscope integrated optical coherence tomography (MIOCT) in anterior segment surgery and to use MIOCT to intraoperatively examine cataract wound integrity in real time. The use of MIOCT could provide direct, intraoperative depth information to the ophthalmic surgeon and potentially improve anterior segment procedures.

 

Methods

 

The MIOCT employed a current-generation commercial spectral domain OCT engine operating at 865 nm center wavelength and 20 kHz A-scan rate with transverse x axial resolution of 7.3 µm x 5 µm in air. The OCT sample arm was integrated with the operative microscope so that the center of the field of view and focal plane of both systems were shared. Corneal dissection for deep anterior lamellar keratoplasty was simulated on a porcine eye. After filling the anterior chamber with viscoelastic, the cornea was partially trephinated. Manual lamellar dissection was performed, and the evolution of the lamellar dissection was monitored with MIOCT. To examine cataract wound integrity, 3 patients undergoing cataract surgery were consented under an IRB approved protocol. Cataract surgery was carried out per standard of care. At the end of the case, MIOCT was used to volumetrically image the main incision before (2 cases) and after (all cases) stromal hydration. Clinical SDOCT was also used to image subjects at post-operative day 1.

 

Results

 

Using MIOCT, the surgeon was able to monitor the progress of manual lamellar dissection (Fig.1). For cataract incisions, the integrity of the wound was readily apparent with MIOCT (Fig.2). Prior to stromal hydration, there was communication between the intra and extraocular environments. After stromal hydration, the opening in the stroma disappeared, though small gaps remained at the internal and external wound edges. Postop day 1 images showed complete closure of the wound.

 

Conclusions

 

MIOCT allows for real-time monitoring of depth dependent dissection in lamellar keratoplasty. MIOCT can be used to intraoperatively confirm wound integrity after cataract surgery. Intraoperative visualization provided by MI-OCT has the potential to improve outcomes for anterior segment procedures. Support: NIH EY019411, EY021522

 

 

Figure 1. Lamellar dissection in a porcine eye monitored with MIOCT.

 

 

Figure 2. Cataract incision in a patient over time with MIOCT and SDOCT.

 

Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 465 clinical (human) or epidemiologic studies: systems/equipment/techniques