Many migrant farmworkers have visual impairment but do not receive routine vision screening

Oct 5 2016

Migrant farmworkers have substantial rates of near- and distant-vision problems, but three-fourths have never had a vision screening test, reports a study in the October issue of Optometry and Vision Science, official journal of the American Academy of Optometry. The journal is published by Wolters Kluwer.

"Vision examinations indicate that a number of farmworkers experience moderate to severe visual impairment, placing them at risk for occupational injury or further vision problems if their vision remains uncorrected," according to the new research by Sara A. Quandt, PhD, of Wake Forest School of Medicine, Winston-Salem, N.C., and colleagues. The study was funded by the National Institute for Environmental Health Sciences.

Three-Fourths of Migrant Farmworkers Have Never Had Vision Screening
The study included a representative sample of 289 Latino migrant farmworkers with uncorrected vision (no glasses) in North Carolina. Subjects underwent eye chart visual acuity tests and Spanish-language interview regarding their vision and vision care.
About 74 percent of the migrant farmworkers said they had never had had a vision examination. When asked why they had not had their eyes checked, 70 percent of farmworkers said they had "never thought about it." Another 14 percent cited costs or lack of insurance.

Vision screening found that 1.7 percent of the farmworkers had moderate to severe impairment (20/40 or worse) in distance vision. Another 6.9 percent had moderate to severe impairment in near vision.

Older age was a significant risk factor: 4.5 percent of workers aged 40 or older had moderately to severely impaired distance vision, compared to 0.5 percent for those under 40. For near vision, the age-related difference was even greater: 21 percent versus 0.5 percent.

Some farmworkers with moderate to severe impairment on vision screening did not identify themselves as having any vision problems in interviews (low sensitivity). Nearly all farmworkers who had no impairment on vision screening said they had good vision in the interviews (high specificity).

Migrant farmworkers are exposed to a wide range of environmental risk factors—including chemicals, mechanical devices, crops and other plants, dust, and sunlight—that could lead to occupational eye injuries and diseases. The new study confirms previous reports that Latino migrant farmworkers receive little or no vision screening.

"Farmworkers with visual impairment are at a higher risk of injury because they may not recognize cues that can alert them to potential occupational and environmental hazards," Dr. Quandt and coauthors write. For example, vision problems might increase the risk of slips and falls, especially at times of low light. Impaired near vision might increase the risk of injuries related to sharp tools or objects.

The authors note some limitations of their study—including potential bias related to which workers agreed or declined to participate.

"Our findings indicate that some farmworkers have serious visual impairment, and they do not obtain routine eye examinations," Dr. Quandt and colleagues conclude. They suggest that offering vision examinations at farmworker residential sites might help increase awareness of the need for regular vision screening. They also call for further studies including more comprehensive assessment of eye health in this vulnerable group of workers.