Standardized language describes trauma to globe

November 1, 2008

Using standardized terminology, such as that in the Birmingham Eye Trauma Terminology system, to describe trauma to the globe eliminates misrepresentation of the injury.

Key Points

Hong Kong-Using standardized terminology to describe trauma to the globe is important to avoid misrepresentation of the injury. Ferenc Kuhn, MD, PhD, explained the recently devised Birmingham Eye Trauma Terminology (BETT) system at the World Ophthalmology Congress.

"This seems like a very insignificant issue," Dr. Kuhn said. "However, when physicians, for example, give presentations at various meetings, they use terms that can mean one thing for them and something completely different for others. Regarding terminology, our aim is to standardize the language."

About 5 years ago, Dr. Kuhn, associate clinical professor of ophthalmology, University of Alabama at Birmingham, and associates compiled the BETT system.

Before BETT was established, Dr. Kuhn said, a reading of publications left one with a great deal of uncertainty and confusion about what injuries were being discussed. "Blunt trauma," for example, frequently is used.

"When we hear this term, we think we know the meaning," he said. "In reality, we have no idea. For example, in one publication discussing blunt injury, there is no way to know if the author is describing a closed globe injury or a rupture. The difference is that one meaning of the word "blunt" refers to the object that caused the injury and another meaning of the word refers to the outcome of the injury."

Two other such terms that lead to ambiguity are "penetrating" and "perforating," and these two words often are used interchangeably, Dr. Kuhn said. Injuries often are referred to as penetrating, but the reader is not told what the injury is penetrating into; if the injury penetrates the cornea, it is a closed globe injury, and if the injury penetrates the globe it is considered an open-globe injury.

"The value of the BETT system is that each term has a very specific definition. Each term is one to one with the clinical condition. Every term refers to the entire globe. This is important because it means that all uncertainty about the type of injury is eliminated," he said.

Another advantage of the BETT system is that it is fairly comprehensive, according to Dr. Kuhn.

A consideration when defining individual terms is the definition of the eye wall, which includes the cornea and the sclera. In the BETT system, an injury to the choroid or the retina does not play a role in the terminology, because in many cases it is unknown if those two structures are damaged, he explained.

"There are two kinds of injuries: closed and open," Dr. Kuhn said. "There may be a wound to the eye wall that is partial thickness. Injuries to the sclera and cornea do not penetrate those structures into the structures below. In cases in which there is no wound, this is a contusion rather than a blunt injury."

Ruptures are injuries that can be caused by a blunt object that compresses the globe, elevates IOP, and the eye will open at the weakest point, he said. When the object causing the injury was sharp compared with blunt, a laceration is the result. Unlike a rupture, a laceration causes damage from the outside to the inside of the eye.

Several types of lacerations exist, and the most important consideration with all of them is whether the object that caused the injury still is in the eye (intraocular foreign body). If the object is not in the eye, the physician must determine if the object left the eye by the same entry route or a different route. The former is a penetrating injury and the latter a perforating injury with two (entrance and exit) wounds, according to Dr. Kuhn.

"In the pre-BETT era, when an injury was described as a corneal penetrating injury, the physician had no idea if the injury was a closed globe injury that penetrated the cornea or if the injury was an open-globe injury into the globe," he said.

"In the post-BETT era, when a corneal penetrating injury is described, it is a full-thickness wound with a single entrance into the eye. If we don't use standardized terminology when describing the type of mechanical eye injury, we are speaking different languages. If a physician uses terms for which only he or she knows the definitions, people may misunderstand the meaning," Dr. Kuhn concluded.