Eye Trauma

                      Eye Trauma

Corneal Abrasions:
The surface of the cornea is covered by a thin layer of epithelium. The cornea contains more nerve innervation (per surface area) than any other place in the body so these abrasions “hurt like the dickens,” with patients complaining of excruciating pain and intense photophobia. Abrasions are easy to see, even without a microscope, as the raw surface will uptake fleurosceine and glow bright green under a blue light.

Fortunately, abrasions recover quickly and will often completely heal within 24 hours. Until complete epithelial healing you treat with aggressive lubrication and follow these eyes closely to insure the raw wound doesn’t become infected. Many physicians will treat an abrasion with empiric erythromycin ointment as well, reserving more aggressive antibiotics like ciprofloxacin for contact lens wearers and “dirty wounds” caused by tree branches, etc..
If an abrasion does become infected, you’ll see a white infiltrate at the wound. Any abrasion with an infectious infiltrate is officially called a “corneal ulcer.” Depending upon the size and location of an ulcer, you may need to culture the wound and tailor your antibiotic coverage accordingly.

Corneal Lacerations:
Most corneal scratches only involve the surface epithelial layer. If the injury goes deeper into the stroma, then you have a laceration. With any laceration you want to insure that the cornea hasn’t perforated. You can check corneal integrity with the “Seidel test.” You wipe a strip of fluorescein paper over the wound and see if dye flows down the corneal surface, indicating leaking aqueous fluid.
If a patient is “Seidel positive” than you have an open-globe injury - time to call in your seniors for possible surgical repair! 

Orbital Wall Fractures:
The bony orbital walls are thin and tend to break with blunt impact to the eye. This is especially true of the orbital floor and medial wall. These orbital fractures are common and you will see them weekly (usually at two in the morning). 
Most of the time these orbital bones heal fine with no long-term problems, with patients merely having a great deal of orbital and periorbital swelling that resolves over a few weeks. However, sometimes the broken bone creates a “hinge” or “trapdoor” that entraps fat or extraocular muscles. If there is significant entrapment or enophthalmos, we need to repair the break. During surgery we can release the muscle and bolster the floor to keep orbital contents from herniating back through the defect. This surgery is usually performed by an oculoplastics specialist.

Lid Lacerations:
When evaluating lid lacerations, you need to determine if the laceration involves the lid margin and how close the cut is to the canalicular (tear drainage) system. Most of these lid lacerations are straight-forward to repair, though special effort is made to align the lid margins to avoid lid notching and misdirected eyelashes.
If the laceration is medial (near the nose) you need to worry about the canalicular tear system - repair of this drain is much more involved and involves threading silicone tubes down into the nose to keep the canaliculus patent. 

Metal :
Small pieces of metal can fly into the eye – an unfortunate event occurring primarily in welders or construction workers. Particles of metal stick onto the cornea causing small abrasions and discomfort. Metal rusts quickly and will form a rust ring within a day. You can remove metal objects and rust rings at the slit-lamp using a needle. You can also use a small dremel-like drill to drill off the rust-ring. If the rust is deep, or aggressive pursuit seems to be making the situation worse, you can leave the residual rust in place as most of it will eventually migrate to the surface by itself.
Anytime you have metal-striking-metal injuries, you must entertain the possibility of an intraocular foreign body. Small metal fragments can enter the eye at high speed and leave little or no signs of injury. Metal is very toxic to the retina and can kill the retinal cells if not detected. If you have any suspicion for penetrating injury, you should always order a thin-slice CT scan of the head to look for metal pieces not obvious on exam. You want to avoid MRI in this setting to avoid creating a moving projectile inside the eye.

                                                                         Chemical Injuries:
 The first thing you do with any chemical injury is:

Irrigate, Irrigate, Irrigate, Irrigate

The final visual outcome for a chemical burn is going to depend upon how quickly the chemical is washed out of the eye. If a patient calls you with a chemical conjunctivitis, tell them to immediately wash their eyes out! If the ER calls you with a chemical conjunctivitis, tell them to start irrigating immediately - several liters in each eye. Then grab your equipment and pH paper and head on down there!
Acids are less dangerous than bases as acids tend to precipitate denatured proteins and this limits tissue damage. Bases, on the other hand, just keep on going like the proverbial Energizer Bunny so you need to continually irrigate and check the pH until it normalizes.
On exam you want to carefully check the state of the cornea – hopefully, it is still clear. A red, inflammed conjunctiva is actually a good finding: if the conjunctiva is white, that means its blanched out from extreme damage. Be sure to flip the lids and irrigate/sweep the fornices to remove any material that may be retaining chemicals.
Chemical injuries can lead to significant scarring that may require corneal transplant if bad enough, so you want to be very aggressive with that irrigation!! The emergency room has access to a simple device called a Morgan lens to help irrigate via a suspended saline bag. Little kids hate this thing and have to be restrained when using it. 

Hyphema:
A hyphema describes blood floating in the anterior chamber, a common finding after blunt eye trauma. If the bleed is large, the blood will settle out in a layer at the bottom of the anterior chamber. If the entire AC is filled with blood, you’ll see an “8-ball hyphema.” Most of the time, however, the bleeding is microscopic and can only be seen as “red cells” floating in the aqueous fluid.

Open Globe Injuries:
The eye can be perforated many ways , firecracker explosions, gunshot wounds, car wrecks, and domestic accidents . Visual outcome is usually terrible and a blind, painful eye may need later enucleation.
If you suspect an open globe injury you need to evaluate the eye in the operating room. One thing to remember - if you suspect an open globe injury, cover the eye with a shield and don’t push on it. You could extrude the eye contents  if you push on the eye.