A corneal laceration is a cut or tear through the cornea, the clear part on the front of the eye. A cat's claw could do it. Cut all the way through it, and the inside of your eye starts going outside your eye. Not good.
Stuff outside the eye, like bacteria, can go inside your eye. Also not good.
Corneal laceration equals "an ocular emergency", meaning you need to get this handled fast or you are going to lose your eye. You need to see an ophthalmologist right now.
What if you're a dog and the nearest veterinary ophthalmologist is 100 miles away three days a week (200 miles away the other four days)? You're in deep chop suey, that's what. Does your local veterinarian have the expertise, the steady hands, and the necessary magnification to see what he's doing?
And does he have this? This is what it takes to successfully suture the cornea back together. 7-0 means size 0000000 (smaller than 2, 1, 0, 00, etc.). It means tiny. It means eensie-weensie-beensie-teensie tiny. Also, it has to have the special TG140-8 spatula point needle, which is flattened on the end to slip between the microscopically thin layers of the cornea instead of just punching holes in it. You'll need a really tiny needle-holding-forceps, too, since the needle is a nearly invisible splinter.
I have all that stuff on hand (and it's expensive to just keep lying around), and I've practiced, and I can do it. Why? Because some eyes can't wait and many clients cannot or will not travel to the ophthalmologist (and it used to be at least THREE hundred miles). So I learned. My problem is this: I'm still no opthalmologist.
Today I saw a German Shepherd who put his head in front of a moving car last night. His eye has been bleeding. Usually this means that the eyelids or the skin around the eye is injured — it wouldn't be the eye itself that was bleeding… usually. This guy's eye had a dark red instead of a white, and his cornea was split horizontally about 2/3 of the way across. His iris had popped forward to plug the hole (which is where the blood had been coming from — cornea has no blood vessels, iris has lots of them).
It happened last night. The cornea wasn't cut. The eyeball was hit so hard that it burst. The rest of the eye structures can't be in good shape. Regardless of who works on this eye, there's a good chance he'll wind up losing it, but they really should see a veterinary ophthalmologist. Money is an issue, and travel is an issue. So, I sewed his cornea back together and put his iris back inside, and filled him full of anti-inflammatories and antibiotics and we'll see what happens. He won't see what happens, at least out of that eye. We'll probably wind up taking it out when it goes to heck, but they wanted to try.
If it does okay, I'll post a follow-up picture. If not, well…