I. What is the ocular surface? The “ocular surface”, as the name suggests, is the outer surface of the eye, which anatomically consists of the surface tissue between the upper and lower lid margins, mainly the conjunctiva and cornea. The cornea and conjunctiva are located on the very surface of the eye and are the eye’s first line of defense against external damage, but they are also the eye tissues that are most vulnerable to accidental injury. Let’s learn more about the cornea and conjunctiva. 1. What is the cornea? The cornea, also known as the “black eye”, is a transparent, non-vascularized tissue. Light enters the eye through the transparent cornea and allows us to see, so the cornea is also known as the window of the eye. The cornea is divided into five layers, but only the frontmost epithelial layer can be regenerated after injury, leaving no traces of damage, while the other layers will leave white scarring of varying intensity after injury, thus affecting vision. 2.What is conjunctiva? Conjunctiva is a thin and transparent mucous membrane, attached to the back surface of the eyelid, to the upper and lower vault turn covered in front of the eyeball, and continued in the corneal epithelium. The conjunctiva is rich in blood vessels, sometimes we see redness in the eyes, it is likely that the conjunctiva is congested. Second, what are the common accidental injuries to the ocular surface? What are the symptoms after the injury? Common ocular surface injuries include mechanical ocular surface injuries and ocular surface burns. 1, mechanical ocular surface injury conjunctival injury: including conjunctival puncture wound, poke wound and conjunctival foreign body. After the injury, children can have crying and tearing, bleeding and not open their eyes, and older children can complain of foreign body sensation and pain. Corneal injury: The cornea is located at the front of the eye, so it is more vulnerable to mechanical trauma. Corneal injury mainly includes the following three aspects: ①, corneal epithelial abrasion: nails, tree branches, pieces of paper, etc. may become injury-causing objects. Due to the epithelial detachment of the rich sensory nerve fibers exposed, the child will experience severe pain, photophobia, tearing and foreign body sensation. ②, corneal foreign body: there are many types of corneal foreign bodies, including metal, plant foreign bodies such as: grain husk, grass, seeds, etc., but also can be wind sand, dust, flying insects, gravel, etc.. After corneal foreign body injury, there are mostly tears and foreign body sensation, unwilling to open the eyes. ③, corneal laceration: can be divided into lamellar laceration and whole layer laceration. The cornea is only partially ruptured in lamellar laceration, and the contents of the eye do not flow out. After the injury, children can show symptoms such as pain, tearing, photophobia and vision loss. Full-layer laceration is usually caused by children accidentally sticking their eyes when playing with scissors, needles, bamboo sticks, etc., and is often accompanied by discharge of eye contents. The child may feel “hot water” coming out of the eye, combined with tearing and loss of vision. Sometimes due to the child will not express their feelings, perforation injury after the irritation symptoms are not obvious, parents often ignore the existence of trauma, until the occurrence of infection to the doctor. 2, eye surface burns: acid and alkali chemical substances, hot water and fireworks and other splashes into the eye, according to the chemical nature of the causative agent, temperature, retention time, etc. will cause different degrees of burns on the eye surface structures, including the conjunctiva and cornea, the worst will lead to blindness. The most common chemical injury in children is lime burn. The conjunctiva may show congestion, edema and even pale necrosis after the burn. The corneal epithelium is edematous, the parenchyma is cloudy, and even lysed and perforated. Burns tend to accrue to the eyelids at the same time, manifesting as flushing, blistering, and vesiculation of the nicotine skin. Late burns will appear corneal vascularization, lid adhesion, eyelid deformity and other manifestations. Third, the treatment and prognosis of ocular surface trauma The ocular surface is the first defense barrier of the eye, after the injury, in addition to the lesion of the ocular surface itself, it will also lead to pathogenic microorganisms and other pathogenic microorganisms to enter into the eye and cause intraocular infection. At the same time, corneal injury often affects the vision of children, so the active treatment of ocular surface injury is very important. Mechanical ocular surface injury treatment: conjunctival injury: large-scale conjunctival laceration requires surgical suture, local hemorrhage without special treatment, conjunctival foreign body should be removed. At the same time, antibiotic eye ointment or eye drops should be applied to prevent infection. Because the conjunctiva is rich in blood vessels, conjunctival injury healing is faster, less infection, generally a better prognosis. Corneal injury: 1, corneal epithelial abrasion: epithelial abrasion epithelial barrier role is damaged, easy to infection. So the treatment after epithelial abrasion is mainly to bandage the affected eye, promote epithelial regeneration and repair and apply antibiotic eye ointment and water to prevent infection. Epithelial repair leaves no trace and does not affect vision. 2, corneal foreign body: in principle, should be removed. Especially metal foreign body, plant foreign body should be removed as soon as possible. Because iron, copper and other foreign bodies will produce biochemical reactions in the tissue, causing serious tissue damage. Plant foreign bodies are prone to cause fungal infections, so these two types of foreign bodies should be paid particular attention to. For small non-metallic foreign bodies, such as glass, etc., which are chemically stable, such as not in the pupil area can not be taken. The foreign body must be followed up within 24 hours after removal to observe for infection. Foreign bodies located in the stroma layer will leave cloudy or patchy opacities in the local area after removal, which will have different degrees of impact on vision depending on the location. 3, corneal laceration: lamellar laceration according to the size of the wound, with or without displacement, you can choose to suture or pressure bandage. Whole-layer laceration emergency clearing and suturing the wound, restore the eye’s confined state, to avoid the content of the eye dislodged and reduce the chance of infection. Corneal laceration will produce obvious astigmatism during the wound healing process, especially perforation injury is more significant, so the visual impact is more obvious. Treatment and prognosis of ocular surface burns: Chemical injuries and thermal burns of the ocular surface are difficult traumatic injuries for both adults and children. For chemical injuries, urgent and adequate irrigation is directly related to the prognosis of the key. The pediatrician should be allowed to open his or her eyes, rotate the eyeballs, and adequately flush every corner of the ocular surface using on-site tap water. The eyelids should also be turned to look for any residual injury-causing substances and remove them, but the desired flushing effect is often not achieved due to the uncooperative nature of children. Upon arrival at the hospital, the doctor should further irrigate with saline. Pharmacological treatment of ocular surface burns mainly involves the application of antibiotic eye drops, hormones, vitamin C, collagenase inhibitors, etc. In the early stages of the injury, amniotic membrane transplantation can also be performed. In the late stage, the treatment is for various complications. Mild burns only damage the corneal epithelium, which recovers completely after a few days and does not affect vision. However, moderate to severe injuries can affect vision. In severe cases, the cornea is dissolved and perforated, the contents of the eye are dislodged and blindness occurs, and in some cases, the normal structure of the ocular surface is lost, the cornea is vascularized, the eyelids are adhered to the eyeball, and the eyeball is unable to move. In cases of complete destruction of the ocular surface, reconstruction of the ocular surface and restoration of some vision is very difficult and requires multiple surgeries and a longer period of time.