What property of the eye makes it a dipole?

The property that makes the eye act as a dipole is the difference in electrical potential between the cornea and the retina. This difference creates an electric field, giving the eye its dipolar characteristics. The cornea, being more positively charged relative to the retina, establishes a voltage gradient across the eye, which is fundamental to various physiological processes, including the functioning of retinal neurons and the response to light.

In contrast, variations in light refraction across the eye, unequal distribution of blood vessels, and absorption of light by the lens do not contribute to the dipole properties of the eye. While these factors are important for eye function and vision, they do not create the necessary electrical potential difference that classifies the eye as a dipole. The dipole characteristics are primarily about the electrical charges at different parts of the eye, particularly between the surface of the cornea and the inner structures.