Human Eye Model: A Hands-On Investigation of the Functions of the Parts of the Eye

1.

This is my third year using a variation of this teaching aid. In previous years, I have had students build the eye model using a lens and various materials. Some students enjoyed the challenge, while others found it frustrating. Digitally fabricating the model and printing enough for a half-class set allowed for everyone to enter the lesson on the same playing field. This year felt different in that each student was instantly engaged, and the kit was easy enough to use, so students were only challenged with using the lens to focus the image and later to run through the guided simulations. The digitally fabricated version allowed for more engagement with the content and freed up instruction time so that I could offer more check-ins with groups and more simulations for them to test. 

Working in an emergent, project-based school requires a lot of curriculum development, and it can be difficult to find teaching aids that fully support learning goals. The ability to build a manipulative tailored to the content, is durable, and can be mass-produced quickly frees up prep time and gives me more time to think about differentiation and scaffolding. 

2.

I had anticipated that students would find it difficult to correlate the base with eye anatomy, but they quickly matched it to the vitreous chamber. This gave us a good jumping-off point to think about how the vitreous chamber, vitreous humor, and sclera work together to create a structure for the eye. 

I also anticipated that the flipped image would surprise students, but some found it frustrating. Even after we discussed the brain’s role in correcting the image, some students found it distracting and spent much time flipping and locking the iPad image to produce a right-side-up projection. I’ll have to think about how to approach this best next year. 

Structural issues I came across and will fix for next year were:

• Secure the lenses in the holders because they drop out easily
• Make the lens holder fit into the base more snuggly
• Add one more support between the paper holder and riser to stabilize the model

3.

I first looked at iterations of the hand-built model students used in previous years. I chose which features were most accessible for students and which needed to be reworked. I kept the lens propped up on a holder, a piece of paper to catch the image, and a flat, slotted base design. Changes I made included adding more slots to the base, building a slot for the lens to rest within in the holder, a paper holder that would allow for easy threading of different types of paper during labs. 

I drew my designs by hand first and calculated the measurements. I then built the pieces in Adobe Illustrator. Jaymes helped me speed up the process by sharing shortcuts, and in hindsight, it was unnecessary to do the work by hand first but I did find value in the process of drawing everything out. I added labels to the lens holders to indicate the lens size, changed my cut lines to the appropriate color and width, and then sent it to the laser be cut. I did learn that I need to make sure to create my designs in RGB to avoid having to convert it later. 

After cutting one piece at the Franklin lab, I was able to test the model and make any final adjustments before cutting the rest of the set. I added a front riser at this point. At home, I am using a WeCreat which works a little differently. I was able to use the preview mode to place all of my pieces efficiently and added extra shapes and etchings in the unused space to test out etching settings and to avoid wasting materials. This was helpful because one full 12 inch by 12 inch sheet took an hour and forty minutes to cut and etch on a 40W diode laser. I just received a 20W diode laser for our school, and this experience will help me to plan my lessons accordingly for laser cutting onsite at school.