FittingBox

Optical Fit Pro

When growth and product value are deeply intrecated.

Making a complex measurement protocol usable in real-world conditions. FittingBox develops augmented reality and computer vision technologies for the eyewear industry. Optical Fit Pro is an in-store solution that helps optical professionals guide customers through frame selection, lens customization, and pupillary distance measurement. My mission focused on improving the usability of its measurement protocol while supporting the transition toward a newly structured in-house design team.

Live Site
Live Site

Client

FittingBox

Year

2025

Role

Lead Product Designer

Scope

UX/UI · Workflow Redesign · Product Collaboration · Design Leadership

Location

Toulouse, France

Project Status

Existing product · Redesign work (deployment impact not documented)

DESIGN PROBLEM

Accuracy is only useful when the workflow supports it.

Accuracy is only useful when the workflow supports it.

Accuracy is only useful when the workflow supports it.

Optical Fit Pro relied on a technically demanding measurement process. The design challenge was to improve the user journey while respecting the underlying technology and the operational realities of optical professionals.

RESULTS

A clearer measurement journey

Reworked the structure and presentation of the measurement flow to make the process easier to follow.

Constraints made explicit

Connected interface decisions with technical and measurement requirements rather than treating usability as a purely visual problem.

Cross-functional design work

Worked with product and design colleagues while contributing to the wider organization and continuity of the design team.

USE CASE

Designing for accuracy

Designing for accuracy

Designing for accuracy

The challenge wasn’t simply to explain the protocol better. It was to make complex physical interactions achievable for users who hadn’t designed the technology themselves.

Challenge

A technically functional protocol wasn’t necessarily a usable one.

The measurement process required users to position a tablet precisely, align visual markers, and coordinate several actions.

While the development team was familiar with the procedure, feedback from stores suggested that optical professionals struggled to reproduce it consistently.

The challenge was to improve the experience within strict technical and delivery constraints.

Problem

The interface was expected to compensate for limitations in the underlying technology.

Some interaction improvements required changes to the measurement engine, originally developed as a proof of concept.
These changes were considered too costly within the available timeframe.
As a result, the design work focused on improving guidance, managing errors, and making unsuccessful captures easier to recover from.

Approach

01 — Research: challenging assumptions with observation

We conducted exploratory usability tests with eight FittingBox employees unfamiliar with the measurement process. Participants were asked to complete the protocol on a tablet using an implemented prototype.
None successfully completed the flow. The sessions highlighted difficulties with positioning, understanding instructions, and executing the required actions.
The findings helped challenge the assumption that users would simply learn the protocol through repetition.

02 — Interaction design: reducing cognitive load

I explored alternative measurement flows to reduce the number of simultaneous actions required from users.
The proposed changes included separating critical steps, improving visual feedback, and clarifying positioning instructions. Some structural changes could not be implemented because they required modifications to the underlying measurement technology.
The final scope therefore prioritized improvements that could be delivered within existing technical constraints.

03 — Error recovery: designing beyond the ideal scenario

When capture fails, correction becomes part of the experience. Since measurement capture could produce imperfect results, I also redesigned the manual correction experience.
After learning that the captured images were available in high resolution, I proposed introducing zoom controls to help optical professionals position measurement markers more precisely.
This capability hadn’t been included in the initial functional scope. The feature was developed and released, alongside improvements to error messages, UX writing, and visual guidance.
Rather than relying exclusively on successful capture, the experience gave users better tools to recover from imperfect results.

04 — Balancing usability improvements with engineering feasibility.

The project involved frequent changes to technical requirements and significant pressure on delivery timelines.
I worked with product and engineering stakeholders to explore improvements, document interaction requirements, and identify feasible changes.
While the underlying protocol could not be fully redesigned, several improvements were delivered to production. The experience reinforced an important principle: usability cannot always be solved at the interface level. Sometimes, the interaction model itself needs to change.

Approach

01 — Research: challenging assumptions with observation

We conducted exploratory usability tests with eight FittingBox employees unfamiliar with the measurement process. Participants were asked to complete the protocol on a tablet using an implemented prototype.
None successfully completed the flow. The sessions highlighted difficulties with positioning, understanding instructions, and executing the required actions.
The findings helped challenge the assumption that users would simply learn the protocol through repetition.

02 — Interaction design: reducing cognitive load

I explored alternative measurement flows to reduce the number of simultaneous actions required from users.
The proposed changes included separating critical steps, improving visual feedback, and clarifying positioning instructions. Some structural changes could not be implemented because they required modifications to the underlying measurement technology.
The final scope therefore prioritized improvements that could be delivered within existing technical constraints.

03 — Error recovery: designing beyond the ideal scenario

When capture fails, correction becomes part of the experience. Since measurement capture could produce imperfect results, I also redesigned the manual correction experience.
After learning that the captured images were available in high resolution, I proposed introducing zoom controls to help optical professionals position measurement markers more precisely.
This capability hadn’t been included in the initial functional scope. The feature was developed and released, alongside improvements to error messages, UX writing, and visual guidance.
Rather than relying exclusively on successful capture, the experience gave users better tools to recover from imperfect results.

04 — Balancing usability improvements with engineering feasibility.

The project involved frequent changes to technical requirements and significant pressure on delivery timelines.
I worked with product and engineering stakeholders to explore improvements, document interaction requirements, and identify feasible changes.
While the underlying protocol could not be fully redesigned, several improvements were delivered to production. The experience reinforced an important principle: usability cannot always be solved at the interface level. Sometimes, the interaction model itself needs to change.

OUTCOME & LEARNINGS

Building continuity beyond my project.

Building continuity beyond my project.

Alongside product design, I stepped into broader design leadership responsibilities after the previous lead left.

Team structure

Clarifying responsibilities.

Helped organize design responsibilities, support collaboration, and maintain continuity across product work.

Recruitment & onboarding

Building complementary capabilities.

Contributed to recruiting and onboarding designers, as well as onboarding a Product Manager.

Continuity & handover

Helping the team move forward.

Supported knowledge transfer, team coordination, and continuity during a period of organizational change.

REFLEXION

A better interface can’t fix every technical constraint.

A better interface can’t fix every technical constraint.


This project highlighted the difference between making a process understandable and making it executable. Clearer instructions and better error recovery can improve an experience, but they cannot eliminate every limitation imposed by the underlying technology. It also reinforced the importance of validating technical assumptions with users early, before a proof of concept becomes a commercial product.

VISUALS

From research
to interaction design.

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