7 April 2025

Picture includes grey object with 2 components. The top part is an open cylinder with a slit. And the bottom part is an elliptical extruded shape.
Eye Drop Helper (Positioning and Squeezing Parts) CAD Design
black 3D printed object (open cylinder with a slit).
3D Printed Positioning Component
white 3D printed object (an elliptical extruded shape).
3D-Printed Squeezing Component
black 3D printed object (open cylinder with a slit) and white 3D printed object (an elliptical extruded shape) assembled together.
3D Printed Assembly

During testing of the first iteration of the molded and cast device, we identified a key issue: the walls of the positioning component were too short to keep the eyedrop bottle tip at a safe distance from the eye, making it difficult to avoid triggering the blink reflex. This highlighted the need to determine the optimal distance between the bottle tip and the eye. We addressed this by measuring the average distance at which the blink reflex is activated among team members, which we found to be 3mm. However, since part of the bottle tip extends a short distance along the component walls, we adjusted the wall height to exceed this 3mm threshold. After implementing this change, we tested the updated component among team members and a few others. The feedback confirmed that the bottle tip now maintained a safe and comfortable distance from the eye.

One issue that persisted with the positioning component, even after these adjustments, was that the bottom surface would repeatedly break away from the walls when force was applied to remove the eyedrop bottle from the notch. Initially, we were unsure of the cause, but we soon realized it was due to the lack of fillets connecting the bottom surface to the walls. Without these rounded transitions, stress was concentrated at the sharp 90-degree angles, leading to structural failure. To resolve this, we added fillets at the base of the walls, improving durability by distributing the stress more evenly.

At this point, the positioning component was fulfilling all of the requirements written in the traceability matrix. First, it was able to stabilize the eyedrop bottle at an optimal distance away from the eye to prevent the blink reflex. It also provided a comfortable feel against the eye due to the rounded edges, while enabling optimal positioning so that the eyedrops will enter the eyes without spillage.

The main improvement to the squeezing component was increasing its size to provide a more secure and comfortable grip. Additionally, we found that no separate attachment mechanism was necessary to join the two components. The notch in the positioning component effectively holds the upper part of the eyedrop bottle, while the snug-fit cavity of the squeezing component stabilizes the lower part, ensuring the bottle remains firmly in place during use. Although if time were to allow for it, the idea involving the use of magnets for attachment could still be a plausible avenue to go down to make the two separate components snap together, and possibly make the attachment even more robust.