Eye irrigation techniques
June 30, 2008
For decades, accepting workplace injuries was the norm; a cost of doing business. When an employee was unable to work for whatever reason, the foreman simply replaced him (or her) and the job continued. No one â€” except the injury victim and his or her family â€” gave it another thought. In fact, at the dawn of the 20th century, it was commonplace to factor fatality estimates into large public works projects like dams and bridges.
Later, workplace safety became a focal point through regulation and a greater awareness of the value of employees. Through the years, clear definition of increasingly stringent regulations and the ever-growing concern for the health and well-being of employees has led to advancements in processes, safety procedures and first aid protocols to treat the injured.
Great idea, but…
During the first half of the 20th century, the commercial eyewash as we know it today was invented. Urban legend has it that the first “steady stream” eyewash was devised back then by an industrial plant manager. He was so concerned about his employees’ welfare that he adapted the use of two drinking fountain bubbler heads and valves mounted on opposing sides of a sink.
When activated, the streams formed a double arch that aimed water from the outer perimeter of the sink to its center. An injured victim would place his face into the double streams and irrigate both eyes simultaneously. It was a great concept and one that took the safety industry to a new level over the ensuing 50+ years. Except for one thing: Irrigating with streams that contact the eye at its outer canthus, or corner, and flow inward toward the nose is diametrically opposed to the way we healthcare professionals irrigate eyes.
The lacrimal system
To comprehend the logic behind how the medical community treats eye contamination situations, you first should understand the eye’s lacrimal system. The human eye is equipped with an automatic lubricating and cleansing mechanism called the lacrimal system (see illustration). It consists of the lacrimal gland, which produces tears; the ducts that channel tears from the lacrimal gland to the ocular cavity; and the lacrimal puncta, which are drains that channel excess fluids out of the ocular surface. Importantly, the lacrimal puncta drain excess fluids directly into the nasal cavity. This process is the reason why your nose runs when you cry.
The eyelid also plays a key role. As we blink, the eyelid wipes the cornea, pushing contaminants and excess fluids toward the lacrimal puncta â€” or the ocular surface’s drains.
If a hazardous material is introduced into the eye, nature’s own cleansing mechanism can serve to force the contaminant into the nasal cavity, where it can be breathed into the lungs or swallowed. Obviously, this is not the ideal situation.
Medically accepted eye irrigation
Accordingly, the medical profession teaches and practices irrigating eyes by introducing the flushing fluid at the inner corner of the eye â€” adjacent to the nose â€” and letting it run across the eye to the outer edge. In effect, we irrigate by moving the fluid away from the lacrimal puncta. This is opposite the flow direction of a number of plumbed-in eyewash products. Pushing contaminants toward the nose not only risks introducing them into the nasal cavity, but also can allow the same contaminant to be introduced into the other eye.
The best method of irrigating eyes in a commercial or industrial setting is to use plumbed-in products that mirror approved medical protocols. Eyewash streams that are inverted contact the eyes at the inner canthus or corner, adjacent to the bridge of the nose. Contaminants are thus swept to the outer edge of the eye, where gravity takes over, running them into the eyewash bowl (see illustration).
Laminar flow eyewashes
Additionally, the use of laminar flow design in the eyewash streams is another great idea. A laminar flow is one in which there is an absence of turbulence, because the stream is “built” in layers. Turbulence or inconsistencies in the flow stream can strike the eye as a change in total pressure, making the victim much less comfortable with the process. The best approach: Providing an even, comfortable, predictable stream height and circumference, accomplished by using laminar design principles.
Harmonizing in-plant eye injury first response protocols with the downstream approach used in emergency rooms and physicians’ offices is a major step in the right direction.