title: Handheld forward-imaging needle endoscope for ophthalmic optical coherence tomography inspection.
abstract: We report the narrowest to-date (21 gauge, 820-microm-diam) handheld forward-imaging optical coherence tomography (OCT) needle endoscope and demonstrate its feasibility for ophthalmic OCT inspection. The probe design is based on paired-angle-rotation scanning (PARS), which enables a linear B-scan pattern in front of the probe tip by using two counterrotating angle polished gradient-index (GRIN) lenses. Despite its small size, the probe can provide a numerical apertune (NA) of 0.22 and an experimental sensitivity of 92 dB at 0.5 frames. The feasibility of retinal imaging is tested on enucleated ex vivo porcine eyes, where structural features including remnant vitreous humor, retina, and choroid can be clearly distinguished. Due to its imaging quality comparable to a commercial OCT system and compatibility with the current ophthalmic surgery standard, the probe can potentially serve as a better alternative to traditional visual inspection by white light illumination during vitreoretinal surgery (e.g., vitrectomy).
authors.affiliation: California Institute of Technology, Department of Electrical Engineering, Pasadena, California 91125, USA.
authors.forename: Shuo
authors.initials: S
authors.lastname: Han
authors.forename: Marinko V
authors.initials: MV
authors.lastname: Sarunic
authors.forename: Jigang
authors.initials: J
authors.lastname: Wu
authors.forename: Mark
authors.initials: M
authors.lastname: Humayun
authors.forename: Changhuei
authors.initials: C
authors.lastname: Yang
mesh_terms: D000818:Animals; D019723:Endoscopes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005123:Eye / Q000033:anatomy & histology*; D066298:In Vitro Techniques; D008904:Miniaturization; D009339:Needles; D019721:Ophthalmoscopes; D013552:Swine; D041623:Tomography, Optical Coherence / Q000295:instrumentation*