Two areas of the body, the eyes and the testes, are particularly vulnerable to RF heating because there is relatively little blood flow in them to carry away excess heat. Additionally, the lens of the eye is particularly sensitive to intense heat, and exposure to high levels of microwaves can cause cataracts.

The common advice to not "stare" into a microwave is largely a precautionary safety measure rather than an immediate danger. Modern microwaves are built with heavy shielding and a metal mesh on the glass door (a Faraday shield) specifically designed to reflect microwave radiation back into the oven. However, if the door is damaged, warped, or the mesh is compromised, small amounts of non-ionizing radiation could leak out. Because the eye's lens is particularly sensitive to heat and lacks the robust blood flow needed to dissipate it, long-term or intense exposure to leaked microwave energy could theoretically contribute to "microwave cataracts." In 2026, safety standards are incredibly high, but experts still suggest standing at least a foot or two away while the machine is operating. Furthermore, watching a microwave is often discouraged because "superheated" liquids can suddenly erupt when disturbed, posing a significant burn risk to your face if you are hovering too close to the glass when the timer goes off.