One aspect of the present disclosure relates a protective eye cup that protects a small animals eye from developing an ocular opacity in the refractive lens during a vision research experiment. The protective eye cup can include at least a dome and a shoulder. The dome can be shaped with an outer geometry configured to facilitate placement and removal of the protective eye cup. The dome can also be shaped with a hemispherical inner geometry with a height and a radius selected to cover the eye. The inner geometry can define a hollow reservoir configured to hold the eye and an associated hydrating fluid when positioned on the eye. The shoulder can provide a radial edge to the dome that increases a contact surface area of the portion of the dome in contact with the hydrating fluid. The protective eye cup can attach to a region external to the eye based on a surface tension of the hydrating fluid.
