Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to diagnose eye problems in pugs [title] Spot the signs of corneal ulcers. [step] The cornea is the transparent layer on the front part of the eye. In order to see, light needs to pass through it to reach the lens and the retina.

Ending1: The cornea is then constantly lit by ultraviolet rays of light. Watch out for the following cases of corneal ulcers : [substeps] Fluid-filled spots on the cornea/underneath the filter. Ending2: If a dog has corneal ulcers, which is like a divot in the cornea, they will affect the ability of light to pass through the cornea, inhibiting the vision of the dog. [substeps] Signs include your pug holding its eye closed or squinting a lot. Ending3: The retina is the long, bone-like outer layer of the eye, which provides light to the eye. [substeps] You may also see patches of dark, crusty scabs along the inner edges of the corn to look like corneal ulcers. Ending4: Signs of inflammation, fluid buildup, dark gray or cloudy eyespots, and blurry or slanted vision are also common. You may also be told you have overactive retinal glands that have become clogged or are spreading.

Answer format: ending1/ending2/ending3/ending4