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Blind Spots and Peripheral Vision

Aligns with the following AFNR Standard(s): CS.03 and PST.02: Low Alignment

Hazard Overview

Rural farm children learn about agricultural work through observation and participation. Attractive nuisances often exist when young children become attracted to a situation not realizing or understanding the potential dangers. Childhood deaths can be attributed to being run over by an agricultural vehicle or being an extra passenger on an agricultural tractor, skid steer, etc. Children are at risk when they enter into any workspace where the tractor, a farm truck or hauler, skid steer, or lift truck is being used. The blind spots to the side and to the rear of these machines, along with the operator preoccupied by work duties, can combine to cause a fatal situation for children and other bystanders.

Learning Objective for the Demonstrations

To understand the dangers of blind spots related to agricultural machinery and vehicle operation.

Materials Needed

  • 8-1/2” x 11” card stock paper of various colors with a single number, letter, or word printed on each side in print large enough to be seen from anywhere in the room.
  • A circle of chairs with one chair placed in the center facing to the front of the room.
  • A 20” wide screen (cardboard, poster board, etc.) to place behind the volunteers head during the peripheral vision test. Screen could be fitted with a soft bracket that could fit over the back of the chair.

Demonstration 1: Peripheral Vision Test I

Procedure and Key Discussion Points

  1. In a group of 12 or more participants, arrange the chairs in as large of a circle as can be made around a single chair placed in the middle of the room with chairs facing inward (Figure 1).
  2. Select a volunteer to sit on the chair in the middle of the circle with directions to look straight ahead and not to turn their head at any time.
  3. Provide all others with a prepared card to be held in their laps until directed.
  4. Starting with the person directly in front of the volunteer, ask each person to raise their card one at a time until all cards are raised.
  5. Ask the volunteer to name the last number, letter, or word to their right and left that they can see without turning their head. Determine how many cards were raised that could not be seen.
  6. Calculate the “field of vision” (degrees of the circle or percentage of cards which were not seen) which would measure the person’s peripheral vision.
  7. Select another volunteer to repeat the demonstration, but have the persons seated in the outer circle move to a different chair so the volunteer cannot memorize where people were seated. Repeat as needed.

Key Discussion Points

  • Discuss with the student how this demonstration translates to agricultural equipment and child.
  • Average the responses from each person for each replication. Did their field of vision exceed 240 degrees? (Note: A person seldom has peripheral vision nearing or exceeding 240 degrees.)
  • How much variation was there within the group? Account for age differences, persons wearing glasses, sight-impaired individuals, etc.
  • Improvise the lesson with math problems or a writing assignment for students to reflect upon their exposure to the topic of peripheral vision issues.

Circle of chairs
Figure 1: Circle of Chairs

Demonstration 2: Reduced Peripheral Vision

Procedure and Key Discussion Points:

  1. Repeat the Peripheral Vision Test 1, but with a 20” wide screen placed behind the seat of the person sitting in the center of the circle.
  2. Repeat this demonstration and calculate the change in the field of vision.
  3. How much less can be seen with the obstruction in place?

Key Discussion Points

  • Discuss with the student how this demonstration translates to agricultural equipment and children.
  • Average the responses from each person for each replication. Did their field of vision exceed 240 degrees? (Note: A person seldom has peripheral vision nearing or exceeding 240 degrees.)
  • How much variation was there within the group? Account for age differences, persons wearing glasses, sight-impaired individuals, etc.
  • Improvise the lesson with math problems or a writing assignment for students to reflect upon their exposure to the topic of peripheral vision issues.
  • A recommended math lesson involves calculating the reduction in visibility with the screen versus peripheral vision results in Peripheral Vision Test 1.

Take-home Points for the Demonstrations

  • Ability to define peripheral vision
  • Understanding of how peripheral vision impacts the safety of children on the farm

Evaluation

We have provided a one page evaluation which has been designed to be used with participants after each lesson. The answer key is offered below.

Evaluation Questions Answer Key

  1. E
  2. B
  3. C
  4. (student response)
  5. (student response)

Sources

Murphy, D. & Harshman, W. (2015) Skid-steer safety for farm and landscape. Penn State Extension.

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Article Details

Title

Blind Spots and Peripheral Vision

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