It’s well known that lifting a heavy load can hurt the back.

However, researchers are exploring how lifting, pushing and pulling also can result in eye damage.

A four-year study funded by a $1.4 million grant from NIOSH will examine the connection between heavy physical activities and retinal detachment, which occurs when the retina pulls away from its nourishing layer of blood vessels, resulting in potential vision loss.

The team of a half-dozen researchers from the University of Massachusetts-Lowell and Reliant Medical Group in Worcester, MA, intend to gather data from 200 cases in a larger and more detailed study than 2008 research from the University of Bologna, Italy, that associated heavy occupational lifting with risk of retinal detachment.

Beyond trying to solidify the connection between material handling and the eye condition, the researchers also hope to provide recommendations that could better protect workers.

“If we are right, and this study confirms the initial observation, it would add another reason why industries in which there’s a lot of manual material handling may want to increase the introduction of lifting devices and automation,” David Kriebel, professor in the University of Massachusetts-Lowell’s Department of Work Environment, said in an interview with On Research.

Kriebel and his team are looking at how lifting leads to increases in pressure in the eye, and how that pressure may lead to retinal cells being torn from their capillary bed.

Trauma to the head, eye damage and a foreign body in the eye are known causes of retinal detachment, Kriebel said. His team is trying to nail down other causes.

“This is a very dangerous phenomenon,” Kriebel said. “The retinal cells for one reason or another are sort of unplugged. They get detached from their blood supply. Then they die. If that happens, you lose their light-detecting ability and you can lose eyesight.”

How it’s done

Kriebel previously taught in Italy, where he met Stefano Mattioli, lead author of the 2008 study that found “strong associations” of retinal detachment with eye surgery, eye or head trauma, severe near sightedness, heavy lifting and high body mass index. That study examined 61 cases of retinal detachment and 99 control cases.

“We decided it would be a good idea to follow up because one study doesn’t really prove anything. It could be just a chance finding, so it’s important to replicate,” Kriebel said. “Hopefully, we can improve upon his study and see whether it’s confirmed and whether the evidence gets stronger with a second study.”

Researchers plan to examine 200 insurance carriers of various occupational backgrounds from Reliant Medical Group. A questionnaire will ask participants about their job history and how much they lifted, pulled and pushed at those jobs.

Because participants might have difficulty remembering some of this information, the researchers will use a database called O*NET to link a job to the amount of lifting it requires. The database lists the mental and physical demands for thousands of jobs.

Researchers also will explore physical activity beyond work – participants will be asked how much they lift during their hobbies and housework.

Obesity another factor

Similar to the 2008 study, the research team will examine the link between obesity and retinal detachment.

“Obesity, like manual material handling, is something we know has a variety of health hazards associated with it,” Kriebel said. “If our study confirms this, it would add another disease to the list of negative health consequences of obesity.”