Ocular injuries resulting from accidental contact with cactus spines or other plant foreign bodies are the most commonly seen ocular foreign bodies in dogs or cats in desert regions. Other foreign bodies include plastic, glass, pellets or bb’s, grass awns, bristles, thorns, small stones and even popcorn kernels can adhere to the cornea, leading to corneal ulceration, infection, or rupture. Minor injuries may heal without treatment by formation of scar tissue which can lead to decreased vision. More serious injuries may require surgery.
Long cactus spines embedded within the cornea may extend into the deeper tissues of the eye including the iris and lens. These embedded spines are difficult to remove safely without surgery under an operating microscope. During surgery, a precise corneal incision is often required to free the spine from the cornea. If this is required the incision may then be surgically repaired to prevent leakage of the ﬂuid from the eye and seal the wound. In some cases a foreign body may be found completely inside the eye, requiring a more complicated procedure involving a larger incision to facilitate removal. Spines that contact and penetrate the lens can lead to cataracts, as well as, initiate serious inflammation inside the eye. This inflammation can lead to discomfort and even glaucoma.
More commonly we find patients with ocular discomfort associated with multiple small cactus spines called glochids embedded in the pink tissue around the eye (conjunctiva) – in addition to the cornea and eyelids. These spines cause discomfort and can abrade the corneal surface. These tiny bristles require magnification for visualization, and removal is generally performed under anesthesia with the aid of an operating microscope. These bristles can migrate beneath the conjunctival surface and may not be visible, even with the aid of magnification. If they break through the conjunctival surface at a later time, a process which may occur days to weeks following initial exposure, a second procedure is sometimes required to remove additional spines. As with all surgeries, anesthetic and post-operative complications can occur. This is seen rarely with ocular surgery, but serious complications can lead to loss of vision or loss of the globe.