Abstract
Purpose:
Optical coherence tomography (OCT) is standard of care in diagnosing, managing, and monitoring retinal diseases. Intraoperatively, OCT has significant potential in improving vitreoretinal surgical outcomes. We compare the capability of an intraocular 25-gauge B-scan OCT endoprobe to a commercial 18 mm telecentric OCT handpiece in imaging a retinal mimicking phantom through various ocular media used during vitreoretinal surgery.
Methods:
A miniature 25-gauge (0.51 mm) forward-imaging endoprobe was designed, developed and optimized to use with an 850 nm spectral domain optical coherence tomography (SD-OCT) system (Bioptigen, Inc.) The retinal mimicking phantom was constructed by spin-coating layers of Polydimethylsiloxane embedded with scattering particles to create reflectance similar to the retinal layers. Altering the spin coater speed produced the desired thickness of each layer. The probe’s capability to image the retinal phantom through air or through vitreous substitutes including balanced salt solution, viscoelastic material, and perfluoro-n-octane liquid was determined. The retinal phantom was then imaged in real time by the 25-gauge SD-OCT probe and a large 18 mm telecentric OCT probe.
Results:
The 25-gauge SD-OCT probe housing the scanning driver within its handpiece transmitted approximately 700 μW of power. The axial resolution was 4-6 μm and the lateral resolution was 25-35 μm with a scanning range of 1.5-2 mm. The 25-gauge forward-imaging probe was able to clearly resolve the phantom layers in real-time when held 3 to 5 mm from the phantom through air as well as through all of the vitreous substitutes. The best image quality was obtained through balanced salt solution. The image qualities produced by the 0.51 mm endoprobe were similar to those obtained by the 18 mm telecentric probe when set at a comparable scanning range of 1.5 mm.
Conclusions:
A miniature intraoperative forward-imaging SD-OCT endoprobe was developed that is capable of imaging a retinal mimicking phantom through air and various vitreous substitutes. The 25-gauge SD-OCT endoprobe is capable of being coupled with any OCT system, and has potential to guide real-time intraocular surgery in the future. The retinal mimicking phantom permits image quality comparisons between OCT devices.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
688 retina •
764 vitreous substitutes