Combined microwave energy and fixative agent for cataract induction in pig eyes

Abstract

We describe a technique used in enucleated pig eyes to create a uniformly hardened lens nucleus and an anterior capsule similar to the cataractous human lens. After treatment with microwave heat and a fixative agent, the pig eyes have clear corneas, anterior capsules with less tension and elasticity, and harder lens nuclei, with a consistency similar to that of a nuclear sclerosis grade I to V in the Emery-Little classification. The eyes can be used by residents in training to practice various phacoemulsification techniques, including continuous curvilinear capsulorhexis, hydrodelineation, sculpting, divide and conquer, phaco chop, and nondividing phacoemulsification.

Partial Oxygen Pressure Affects the Expression of Prognostic Biomarkers HIF‐1 Alpha, Ki67, and CK20 in the Microenvironment of Colorectal Cancer Tissue

“…Comparatively, microwave irradiation improves the penetration of fixatives and antibody solutions into CRC tissues, resulting in efficient fixation and reduction of nonspecific antigen [41]. After treatment with microwave heat and Finefix, the tissues have clear morphology with less tension and elasticity and harder nuclei [42]. The utilization of microwave offered a reproducible method for quantifying antigenicity.…”

Rabbit models for continuous curvilinear capsulorhexis instruction

“…The amount of fixative used (2% to 8% PFA) was a fraction of the amount of formaldehyde used in previous studies of porcine eyes, which ranged from approximately 25% to more than 30%. 17,18 Compared with the higher fixative concentrations used in these porcine studies, which mandated more compressed treatment times to avoid overtreatment (1 to 2 minutes, 17 unspecified 18 ), the lower fixative concentrations used here allowed expanded treatment times that could be more easily controlled to dial-in a desired human equivalent age for the treated rabbit capsule.…”

“…Methods to harden animal lenses have been described including the injection of fixative directly into the lens 16 and the use of microwave. 18 It is possible that the inclusion of such steps will extend the utility of these rabbit models to the subsequent steps of cataract surgery.…”

“…Development in this area has progressed from the use of cadaver eyes 14,15 to less expensive and more readily available porcine eyes that are treated with a fixative to decrease capsule elasticity. 16–18 The porcine eye models typically use a strong fixative with more than 30% formaldehyde and require care to guard against excessive loss of capsule elasticity from prolonged treatment but at the same time to avoid under treatment. Furthermore, the degree to which the treated porcine anterior capsules have biomechanical properties resembling those of the human anterior capsule in patients has not been assessed objectively.…”

Update on Simulation-Based Surgical Training and Assessment in Ophthalmology

“…One study achieved the highest level of validity evidence, corresponding to a well-defined process for developing the simulator content, including expert review. 58 Validity of Models. The primary purpose of 23 trials was to investigate the validity of 9 different models ( , and a combined model (n ¼ 1).…”