All imaging was performed under general anesthesia as already described above. OCT (SOCT Copernicus; OPTOPOL Technology S.A., Zawiercie, Poland; wavelength 840 nm, axial resolution 6 µm, and transversal resolution of 12–18 µm) was performed bilaterally on all rabbit eyes. To visualize the iridocorneal angle, including the inflow area of the implanted microstent in case of operated eyes, the animals were positioned upright in front of the device and the eye was opened by a lid speculum for OCT examination. OCT was carried out 2 weeks as well as 4 weeks after surgery and then subsequently every 4 weeks until the end of the study to evaluate the correct position of the implants and to detect implant dislocations at an early stage.
MRI of the microstents was performed with an ultrahigh field small animal MR scanner (7 Tesla, BioSpec 70/30 USR, gradient: BGA 20S, gradient strength: 200 mT/m, Bruker BioSpin MRI GmbH, Bremen, Germany) equipped with a 152-mm (inner diameter) volume resonator in transmit-only mode, and a 2 × 2 receive-only surface coil in receive mode (both Bruker). Animal eyes were imaged in coronal and sagittal slice orientation using a T2-weighted TurboRARE sequence (TE/TR = 35/4000 ms, rare factor = 8, averages = 1, field of view = 20 × 18.7 mm, matrix = 133 × 125, slice thickness = 1.0 mm, in-plane resolution = 150 µm × 150 µm).
For the MRI measurement, the breathing rate of the rabbits was monitored (Model 1030, SA Instruments Inc., Stony Brook, NY) during the scans. To prevent eyes from drying Vidisic eye gel (Bausch & Lomb Inc., Rochester, NY) was used and the lids were carefully shut. The surface coil was placed proximal to the closed eye. The first MRI was conducted 4 weeks after surgery and subsequently every 4 weeks until the end of the study.
MRI of the microstents was performed with an ultrahigh field small animal MR scanner (7 Tesla, BioSpec 70/30 USR, gradient: BGA 20S, gradient strength: 200 mT/m, Bruker BioSpin MRI GmbH, Bremen, Germany) equipped with a 152-mm (inner diameter) volume resonator in transmit-only mode, and a 2 × 2 receive-only surface coil in receive mode (both Bruker). Animal eyes were imaged in coronal and sagittal slice orientation using a T2-weighted TurboRARE sequence (TE/TR = 35/4000 ms, rare factor = 8, averages = 1, field of view = 20 × 18.7 mm, matrix = 133 × 125, slice thickness = 1.0 mm, in-plane resolution = 150 µm × 150 µm).
For the MRI measurement, the breathing rate of the rabbits was monitored (Model 1030, SA Instruments Inc., Stony Brook, NY) during the scans. To prevent eyes from drying Vidisic eye gel (Bausch & Lomb Inc., Rochester, NY) was used and the lids were carefully shut. The surface coil was placed proximal to the closed eye. The first MRI was conducted 4 weeks after surgery and subsequently every 4 weeks until the end of the study.
