PurposeTo evaluate porcine vitreous flow and water flow rates in a new prototype hypersonic vitrectomy system compared to currently available pneumatic guillotine vitrectors (GVs) systems.MethodsTwo vitrectors were tested, a prototype, ultrasound-powered, hypersonic vitrector (HV) and a GV. Porcine vitreous was obtained within 12 to 24 h of sacrifice and kept at 4°C. A vial of vitreous or water was placed on a precision balance and its weight measured before and after the use of each vitrector. Test parameters included changes in aspiration levels, vitrector gauge, cut rates for GVs, % ultrasound (US) power for HVs, and port size for HVs. Data was analysed using linear regression and t-tests.ResultsThere was no difference in the total average mean water flow between the 25-gauge GV and the 25-gauge HV (t-test: P = 0.363); however, 25-gauge GV was superior (t-test: P < 0.001) in vitreous flow. The 23-gauge GV was only more efficient in water and vitreous removal than 23-gauge HV needle-1 (Port 0.0055) (t-test: P < 0.001). For HV, wall thickness and gauge had no effect on flow rates. Water and vitreous flows showed a direct correlation with increasing aspiration levels and % US power (p<0.05).ConclusionsThe HV produced consistent water and vitreous flow rates across the range of US power and aspiration levels tested. Hypersonic vitrectomy may be a promising new alternative to the currently available guillotine-based technologies.

PurposePreliminary assessment of a new prototype ultrasound-based hypersonic vitrector (HV) by qualitatively examining the histopathological changes in the retina and vitreous body after pars plana vitrectomy (PPV) and its ability to fragment vitreous collagen.MethodsFourteen porcine cadaveric eyes, 20 eyes in live swine and six human cadaveric eyes underwent PPV using the HV or a pneumatic guillotine vitrector (GV). An additional 4 porcine crystalline lenses were touched with either the HV or GV for 1 minute. Following PPV, human vitreous was removed and processed for electron microscopy (EM). Eyes and lenses were fixed and sectioned for light microscopy (LM).ResultsThere were no macroscopic retinal or optic nerve defects associated with either HV or GV PPVs. Cadaveric retinal specimens showed separation of the inner limiting membrane (ILM) and vacuolization and fragmentation at the nerve fiber layer (NFL) and the ganglion cell layer (GCL). ILM fragmentation and separation were found after PPV in live swine with both vitrectors. Small disruptions of the posterior capsule or structural lens defects were found after HV touch. The EM analysis revealed more fragmentation of human vitreous collagen fibrils after HV compared to GV PPV.ConclusionsLM and EM analysis of retina, vitreous, and crystalline lens after PPV showed similar morphological changes using the HV or the GV. Vitreous fragmentation appeared more effective with the HV. Overall this study suggests that the HV may be a promising new technology. More work is needed to quantitatively assess its safety and efficacy.

PurposeAssess morphological changes in the retina and optic nerve head (ONH) after pars plana vitrectomy with a new prototype ultrasound‐based hypersonic vitrector (HV).MethodsSix porcine cadaveric eyes, 6 human cadaveric eyes and 14 live porcine eyes underwent pars plana vitrectomy (PPV) using the HV or a pneumatic guillotine vitrector (GV). One extra eye from each porcine group had no procedure done, being used as a control. Eyes were fixed in formalin, examined macroscopically and processed for histological assessment. Microscopic analysis included assessment of any morphological intraocular change especially to the retina and ONH. Comparison was made between non‐vitrectomized (intenal control) and vitrectomized areas, respectively nasal and temporal to ONH .ResultsThere were no macroscopic retinal or ONH defects associated with either HV or GV PPVs. Microscopically, cadaveric human and porcine retinas showed focal vacuolization and fragmentation at the nerve fibre layer and the ganglion cell layer as well as separation of the inner limiting membrane (ILM). Eyes from live swines following PPV with both vitrectors showed ILM fragmentation and separation. There were no differences between the ‘non‐vitrectomized’ nasal (control) and vitrectomized temporal areas of the ONH with HV.ConclusionsMorphological examination of retina and ONH with light microscopy after PPV showed similar features using the HV or the GV. The HV might be a promising new alternative to the currently commercially available GV for PPV.