Optimal microwave settings for porcine cataract formation for Wet Lab Training

Abstract

Objective: The objective of this study was to determine the optimal microwave power in watts (w) and time in seconds (s) needed to form a visually significant cataract in fresh ex vivo, cadaveric, porcine eyes that can serve as a low-cost, surgical model for trainees.
Methods: Twenty-four fresh, cadaveric, porcine globes were tested. Sets of eight globes were individually
microwaved at 1000w, 500w and 100w, the first eye for a time of 3s followed by subsequently adding 1s more for each additional eye up to 10s. The corneas and lenses were then surgically harvested, and the opacification of each was objectively graded using a Pelli-Robson contrast sensitivity chart on a log unit scale of 2.30 (transparent) to 0.00 (total opacification). Lens hardening was subjectively graded on a scale of soft, medium, hard, and scarred.
Results: At 1000w, lens opacification became significant beginning at 5s and hardening took place by 8s. At
500w, lens opacification became significant at 6s and hardening took place at 8s but quickly transitions to
scarring by 9s. At 100w, significant lens opacification and hardening did not occur by 10 seconds. The cornea
remained transparent at all parameters, except for a trend toward opacification at 500w after 9s.
Conclusion: Optimal settings for microwaving fresh, cadaveric porcine eyes were found to be 1000w for 5 to
10s. These settings induced fully opacified cataracts with a range of soft to hard lenses without leading to severe scarring of the lens-capsule complex or visually significant corneal opacification.