What dye is commonly used to stain the cornea during eye examinations?

Fluorescein is the dye commonly used to stain the cornea during eye examinations due to its excellent visibility under blue light. This dye binds to areas of the corneal epithelium where the surface is damaged or compromised, thereby allowing the healthcare provider to assess the integrity of the corneal surface. When fluorescein is applied and the blue light is shone on the eye, any abrasions, ulcers, or other defects in the cornea fluoresce bright green, making them easy to identify.

Using fluorescein is a standard practice in both routine eye exams and specific situations like contact lens fittings or evaluating corneal injuries. The other options, while they may also be used in a variety of medical scenarios, do not have the same specific application or effectiveness in visualizing corneal injuries under examination conditions.