User Testing and Functionality
In order to verify our product’s functionality and usability, our group conducted a product use survey, where our product was presented to our friends and fellow students around campus to try out. They were shown how to use and operate our product. Most students were uncomfortable using a shared eyedrop bottle by squeezing the artificial tears into their eye, but all surveyors practiced squeezing the eyedrop bottle with and without our device and placed the positioning device on their face. This data is still valuable for us and will indicate to us if we are in the right direction and if they are anything we overlooked.
Each question has a corresponding design input, and each will be analyzed. At the time of analysis, the number of participants totaled 13 on 4/28/2025.
Q1: How difficult is the process of applying eyedrops without an assistive device in your day-to-day life?
62.5% of users stated that it was “somewhat difficult”
30% of users stated that it was “somewhat easy”
Q2: Did you feel that the device made it easier for you to dispense eye drops out of the bottle?
92% of users stated “yes”
7% of users said “maybe”
Design Input: Average squeezing force distributed across a larger surface area of the hand due to interfacing with the squeezing component.
According to the participants, our device helps the majority of users squeeze the eyedrop bottle, as it effectively distributes the necessary squeezing force, allowing an individual to use all five fingers to squeeze the bottle.
Q3: How effective was our device in helping position the eye drop bottle in alignment with the eye?
85% of users stated that it was “extremely helpful.”
15% of user stated that it was “Good”
Design inputs: Bottle positioned to be able to drop the drug within 10 mm of the iris.
Based on the participants’ response to Q3, they found the positioning device to be extremely helpful in alignment. While not all participants actually placed eyedrops into their eyes, this is still a strong indicator that the positioning component is working as intended and is able to meet the 10mm requirement.
Q4: Did the positioning component of the device feel comfortable on and around the eye-area? Did it hurt you in any way to have the positioning component on your face?
54% of users stated “I could feel it, but it did not feel bad in any way”
46% of users stated “No! it felt like nothing
Design Input: Positioning attachment filleted – smooth surfaces with no sharp angles.
Based on the user feedback, the positioning component felt comfortable without feeling any pointy edges. This indicates that our positioning component is currently comfortable in the hands of our users and that our design input has been met.
Q5: How comfortable did the device feel on your hands? (How good of a job did we do with making it ergonomic?
69% of users stated “No complaints!”
31% of users stated “Extremely Comfortable”
Design Input: Optimize comfort for users’ hands
Based on the responses, users indicate that the current shape and feeling of the squeezing component are comfortable, and further iteration should maintain this level of comfort.
Q6: Did you think that the device made you blink a lot more than usual?
53% of users stated “Not at all.”
38% of users stated “Sometimes”
8% of users stated “definitely”
Design Input: Maintains a safe distance between the eyeball and the tip of the eyedrop bottle to circumvent the blink reflex.
Our data shows we have some room to improve in this aspect, as some users are still affected by the blink reflex. However, we are on the right track as it is working for the majority of users.
Q7: On a scale of 1 (worst) to 5 (best), how portable do you think our device is?
69% of users stated “5”
31% of users stated “4”
Design Input: An appropriate size that strikes a balance between portability and ease of use
Based on the data, most users think our device has a 5/5 in portability, which could be taken as it is sufficiently portable for its function, and that our product meets our design input.
Testing — Volume Measurements
One issue identified through our research is that standard eyedrop bottles often dispense liquid in a stream rather than in discrete drops when excessive force is applied. In contrast, our assistive device ensures consistent dropwise dispensing by distributing pressure over a larger surface area, preventing the sudden bursts of force that typically lead to streaming. We’ve listed below the calculations involved in our prototype testing process that support our claims.
To begin, the density of the saline solution was determined to be 1.005 g/mL—a value nearly identical to that of pure water, which is expected given that water is the main component of saline.
Next, the mass of 10 drops of the saline solution was measured over three trials using a digital scale. Ten drops were chosen instead of one because the mass of a single drop was too small to register accurately on the scale. The relevant volume was then calculated using the density = mass / volume equation.
Trial 1
Mass of 10 drops of solution: 0.5025 g
Mass of 1 drop of solution: 0.05025 g
Volume of 1 drop of solution: mass / density = 0.05 mL
Trial 2
Mass of 10 drops of solution: 0.5062 g
Mass of 1 drop of solution: 0.05062 g
Volume of 1 drop of solution: mass / density ~ 0.05 mL
Trial 3
Mass of 10 drops of solution: 0.5012 g
Mass of 1 drop of solution: 0.05012 g
Volume of 1 drop of solution: mass / density ~ 0.05 mL
As shown in the calculations above, the use of our assistive device resulted in the consistent dispensing of eyedrops with a volume of approximately 0.05 mL. This value falls squarely within the typical range for an average eyedrop, which spans from 0.035 mL to 0.070 mL. By promoting consistent, controlled dispensing, our device helps minimize medication waste, ultimately making treatment more accessible and affordable for users.
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