Built in Protection
Because of its importance and vulnerability, the eye has evolved a number of effective defense mechanisms to shield it from injury. Its recessed position within the protective orbital bones is the first line of defense for the human eye. Much more than just fashionable accoutrements, the eyelashes and even the eyebrows serve as an early warning system, telling us to blink or move away when something gets close to our eyes. And tears do much more than just express our emotions. They keep the eyes moist and lubricated and they flush foreign matter away from the surface of our eyes. Despite these important defenses, the eyes are still vulnerable to injury. Let’s take a look at some of the more common eye injuries, keeping in mind that while this list is by no means all-inclusive, it will give you a basis for recognizing and managing some of the more common injuries.
Corneal Abrasions
One of the most common injuries occurs when a foreign body or fluid gets onto the surface of the eye, which can cause redness, irritation and tearing. A common scenario would be when a speck of sand blows into your eye and the resulting irritation causes you to rub it. A foreign body such as this speck of sand or anything moving across the surface of the eye can cause a small scratch called a corneal abrasion. Occasionally a foreign body can become embedded in the eye. In either case, your physician can make the diagnosis using fluorescein dye drops and a blue light to detect damage to the cornea. If left untreated, a large abrasion or an embedded foreign body can cause infection or, in the case of a metallic foreign body, deposition of a rust ring. Along with the lining of the mouth and tongue, the epithelial layer of skin on the cornea is one of the fastest areas of the body to heal and a simple corneal abrasion should resolve in 24 to 36 hours.
Chemical Burns
If a harmful chemical, either fluid or less often powder, gets into the eye it can cause anything from mild irritation to a serious chemical burn. The severity of the burn depends on the composition of the chemical and length of time it is in contact with the eye. The most dangerous substances are strong acids or alkali. This is one of the most common eye injuries and severe cases require immediate treatment and evaluation by an ophthalmologist. The pain may make it difficult for the patient to open the injured eye, but the eye should be opened and flushed with clean water or saline even before medical assistance is available. Proper eye protection and eye wash stations in the workplace or school laboratory are essential for preventing and treating this potentially serious injury.
Black Eye
A ‘black eye’ is a bruise caused by bleeding into the facial tissue around the eye. It can be due to an injury to the face or periorbital region and while it is usually benign, it can indicate a more serious injury such as a skull fracture. Treatment consists of applying an ice pack to the area without putting pressure on the eyeball itself. Evaluation by an ophthalmologist is advisable, especially if vision is affected or if there is damage to the eyeball. A simple black eye should resolve in 3 to 5 days. It is important to note that two black eyes, known as ‘raccoon eyes’ can indicate a more serious head injury such as a skull fracture.
Subconjuntival Hemorrhage
A subconjuntival hemorrhage occurs when there has been leakage from a blood vessel into the area between the sclera (white of the eye) and the conjunctiva covering it. While it is usually caused by mild trauma to the eye, a subconjunctival hemorrhage can occur after straining or coughing and occasionally they occur spontaneously. A subconjuntival hemorrhage usually looks worse than it is and generally does not cause pain. In most cases no treatment is required and the area of redness clears over a period of a week or so.
Orbital Fracture
The results of blunt trauma to the eye can include two serious eye injuries, orbital fracture and hyphema. The orbit is the boney casing in the front of the skull that contains the eye. It is composed of seven bones and any of these can sustain a fracture usually due to blunt force from something larger than the eye itself, such as a ball or fist. An orbital blowout fracture occurs when the increased pressure in the orbit from the blow causes the weakest point at the floor of the orbit to ‘blow out’. Signs and symptoms can include black eye, swelling, difficulty moving the eye and abnormal position of the eye. Prompt medical attention and evaluation by an ophthalmologist is essential and surgery is often necessary to correct the injury.
Hyphema
A hyphema is caused by bleeding into the anterior chamber of the eye, the front part of the eye between the cornea and the iris. It is usually caused by blunt trauma to the eye and is manifested by pain, sensitivity to light and blurred vision. Evaluation by an ophthalmologist is essential to confirm the diagnosis and determine the course of treatment. In mild cases hyphema may resolve spontaneously with bed rest, elevation of the head of the bed and a protective eye shield. Serious cases can cause an elevation of pressure within the eye which could lead to glaucoma and require surgery.
Penetrating Eye Injuries and Lacerations
A penetrating eye injury is where the outer membranes of the eye are disrupted and requires immediate evaluation and treatment. It can be one of the most serious eye injuries and can lead to significant loss of vision or loss of the eye without proper treatment. Some common objects responsible for penetration injuries of the eyes include rocks, lumber, fishing weights, baseballs, sticks, knives, scissors and screwdrivers. A laceration or cut in the tissue surrounding the eye requires evaluation to rule out a more severe accompanying eye injury. It may also require the skilled hands of an ophthalmologist or plastic surgeon, particularly when the eyelid is involved, to insure a good cosmetic result. You should always check with your health care provider if you have any questions about a possible injury to your eyes. In our next article we’ll look at some common eye infections.