Which laser is most likely to cause retinal damage to the unprotected eye?

The Nd:YAG laser at 1064 nm is particularly capable of causing retinal damage to the unprotected eye due to its wavelength being in the near-infrared region. This wavelength can penetrate the ocular media (like the cornea and lens) and reach the retina, where it can result in thermal injury. The energy from this wavelength is less scattered by the eye tissues compared to those at longer wavelengths, which means more energy can be focused on a specific area, resulting in potential damage.

In contrast, the other lasers listed have wavelengths that either do not penetrate as deeply or are absorbed more by the front structures of the eye, such as the cornea, preventing them from reaching the retina. For instance, the Er,Cr:YSGG and Er:YAG lasers operate at wavelengths that are better absorbed by water and are less likely to penetrate through the lens and cornea effectively. Similarly, the CO2 laser at 10,600 nm is strongly absorbed by water, which results in limited penetration into the eye's internal structures. Therefore, while all lasers should be treated with caution when used near the eyes, the Nd:YAG laser poses the highest risk for retinal damage among the listed options due to its specific wavelength and ability to penetrate ocular