Keep an Eye on Your Dairy Farm Employee Vision Health

Maristela Rovai, Assistant Professor & SDSU Extension Dairy Specialist

Do the employees see what they learn?

Maristela Rovai
Maristela Rovai

In response to producer requests, SDSU Extension’s dairy team has developed various training (i.e., milking school, dry cow therapy, maternity, and cow handling) for dairy employees in both Spanish and English. On several occasions, producers and managers have voiced their concerns whether the workers understood their directions after farm trainings with both long-term employees and recent hires. How do producers detect if employees are developing the expected skills? A dairy farm typically involves many day-to-day operations, use of machinery and equipment, and, most importantly, following the recommended milking procedures. An essential step in the milking process includes foremilk stripping that detects mastitis, which include “clotty, stringy, or watery” milk. Besides signs detection for mastitis control, following written protocols and safe medication practices; optimal vision is a requirement of a farmworker. Producers frequently observe employees’ inconsistencies when performing the mentioned activities. Surprisingly, during Extension trainings, the team found that some of the employees have problems with written documents and projection screen, this issue is not only due to literacy problems but in most cases an eye vision issue.

With the aim to understand more about vision impairment within this population, the SDSU Extension dairy team researched dairy employees’ Health Status with a focus on vision care. Ninety dairy workers from four different dairy farms along the I-29 corridor (~9,000 lactating cows) were included in this study. The objective was to detect possible impaired vision issues within dairy farm employees. Majority of the participants (age range 28–34 years, 80% were males) were originally from Guatemala or Mexico. A vision test and a brief health assessment questionnaire were used to collect the study’s information.

In the study, participants vision was tested with the handheld Spot Vision Screener device (Welch Allyn® INC, Skaneateles Falls, NY) to detect vision issues with dairy farm employees’ during the regular farm trainings and meetings. The device displays in less than two seconds a report of pupillary diameter (direct response to illumination), ocular alignment (strabismus or abnormal eye alignment), and referral recommendation that is: “All measurements in range” or “Complete eye exam recommended”. The vision screener test correctly identified issues whether or not the participants wore contact lenses or glasses. A more comprehensive report available for printing included information on myopia (nearsightedness), hyperopia (farsightedness), anisometropia (unequal refractive power), astigmatism (blurred vision), strabismus (eye misalignment), and anisocoria (unequal pupil size).

The Impact of Vision Problems

The farm employees’ daily tasks included reproductive and maternity care, hospital, calf care, and milking parlor routine. The decreased ability to see will have an impact on employees performing their normal daily farm activities, including, but not limited to, following practices and procedures, safety awareness and hazard recognition. Poor vision can affect one’s quality of life, self-esteem, independence, and mobility.

As our results showed, most of the farm employees are Latinos, and vision care has not been taken seriously. Figure 1 shows that over 44% of the participants have never visited an eye care professional either due to cost or language barrier.

The eye-test revealed that 75% of the participants did not present any eye vision impairment (Figure 2). However, the eye vision results showed a range of a potential vision disorders for a few of these participants due to their results being close to the criteria cut off for referral. The participants were encouraged to follow a better health recommendations, including visits to an eye care specialist. In this study, 60% of the employees referred for follow-up care with an eye care specialist (Figure 2) were milkers. Ninety-five percent of the participants do not have vision insurance. In general, 51% of the participants considered their vision as: in good condition, 20% as excellent, 16% as fair, and 13% as poor. During this study, issues of color deficiencies (known as colorblind) on employees were also detected. Paint sticks red, pink, and green are used for sorting cows for various protocols; however, employees with color deficiencies shared that they usually make mistakes because they are unable to distinguish specific colors.



Thus, an employee’s eye health assessment after an employee has been hired is advised. The manager needs to remember that the employee cannot perform their job duties adequately if their vision is impaired. The cow’s wellbeing and quality of milk might be at risk due to the milkers vision challenges. Preliminary evidence using the screener suggested that future vision care program should be developed for farm workers, particularly for the milkers subgroup.

How can you help your employees?

A health workshop can provide more awareness to farm employees about the importance of following a healthier life including eating choices and physician checkups. We believe that bringing health information and awareness into focus will keep farm workers motivated to follow a healthier life in general. Employees play an important role at the farm, where most of the farm productivity is in their hands.

Recommendations that can help your employees take better care of their vision:

  1. Eyes’ health and other diseases:
     Remind them that vision capacity decreases over time (age effect) and it is important to be aware of other diseases like diabetes which can lead to vision complications.
  2. Eye doctor regular visit: Share the contact of an optometrist for routine eye care visits (every 1-2 years) or an ophthalmologist for medical and surgical treatment of serious eye conditions. Optometrist & ophthalmologist with interpreters would be helpful.
  3. Contact lens: Remind them to be caution when exposed to dusty environments or working with chemicals. Wearing dirty contact lens can lead to infections, and even damage their long-term vision.
  4. Wear sunglasses: Remind them to wear sunglasses when exposed to outdoor activities which will protect the eyes from the sun’s harmful UV-A and UV-B rays.
  5. Provide them safety glasses: OSHA recommends wearing an eye and face protection (29 CFR 1910.133) when workers are exposed to eye or face hazards such as flying objects, liquid chemicals, acids or caustic liquids, chemical gases or vapors, or other potentially injurious. Many activities on a farm (i.e. milking parlor, maternity, cleaning) may expose the eyes to hazardous materials including chemicals and eye’s protection is advised to fully cover the eyes, including the sides.
  6. Vision testing tools: Help your employees to identify eye vision problems. There are inexpensive ways of helping to check your employees eye vision as the: a) Snellen Chart as used for driving test which will be testing impaired eyesight and primarily distance vision. b) Jaeger Eye Chart used for reading up close and determining visual acuity, or general visual performance. c) Ishihara color test used to diagnose color blindness.
  7. When hiring: Ask if your employees have distance glasses (e.g. to drive or watch TV) as some people do not like to be seen with them or wear them all the time. Encourage them to wear their glasses and do periodically checking up.
  8. Health and safety workshop: Create or provide health and safety workshops, with community sources, once or twice a year in their native language.



It is important to also remember when writing protocols or a simple note to the employee, to use a reasonable font size (i.e. 12 or higher), concise and readable.

If you are a producer who employs migrant workers and need assistance in training your workforce on various dairy related issues, please contact Maristela Rovai.


This study was funded by the High Plains Intermountain Center for Agricultural Health and Safety. We would like to thank to the producers in S.D. for allowing us to conduct the study in their farms. We would like also to thank the dairy farm employees for their time and appreciation of participating in the study.

Editor’s note: Maristela Rovai is Assistant Professor and South Dakota State University Extension Dairy Specialist. This article appears in the I-29 Moo University newsletter for July 2020 and is used here with permission. Written collaboratively by Maristela Rovai and Leyby Guifarro.


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