Safety-Critical Software for Eye Diagnostics

Safety-critical software for a laser-based eye-diagnostic device

MADIS developers help build the application that connects physicians with an optical biometry device used to plan cataract surgery – controlling the laser, analysing data and visualising results on a touchscreen.

At a glance

20,000

automated regression tests run every night

~25

specialists in the development programme

Touchscreen

data analysis and device control in one interface

Summary: An eye-diagnostic device that uses a laser must be precise and, above all, safe. For a German medical technology company, MADIS contributed to the modular application that controls the device, analyses diagnostic data in real time and shuts the laser down automatically if needed – backed by a highly automated test infrastructure for a strictly regulated market.

The client

The client is a German medical technology company. The device in this project is already on the market and is used in cataract diagnostics: it measures the eye with a laser of a special spectrum, including depth, to help select the right intraocular lens before surgery.

The challenge

The device has three layers: the physical hardware, embedded software that controls the lasers, and an application that ties everything together and gives the physician an interface. The application is the part that keeps evolving, and it has to do so without compromising patient safety.

Because a laser is directed into the patient’s eye, the tolerance for error is extremely low. The medical device market is regulated differently in each country, which also affects how features appear, and every change has to be thoroughly tested and documented.

• Patient safety: the system must detect if the laser is stronger than allowed and stop automatically – a failed measurement is always preferable to harm.
• Very high test expectations: coverage that is optional elsewhere is essential here.
• Extensive documentation required by law, differing by country.

Our approach

Modular application development

A modular application connects the physician with the device, enabling laser control, data analysis and visualisation of the results on a touchscreen interface. A MADIS lead developer also took part in planning and in preparing user stories with the product owner and business analyst.

Test infrastructure and automation

The team built test automation as part of the domain itself: around 20,000 regression tests run every night, using pre-manufactured artificial eyes. Keeping the full run within one night became an engineering task of its own.

Working with medical experts

Physicians with PhDs provide the domain knowledge, so that the software reflects clinical reality as well as technical requirements.

The solution

The application collects and analyses diagnostic data, displays it to the physician in real time and controls the laser system, regulating or stopping it automatically when safety requires. It combines local hardware with cloud components in a hybrid setup.

Results

• Higher diagnostic accuracy: the device can detect lens clouding more precisely than the human eye and measures depth as well as the surface.
• Safer surgery planning: a low error threshold makes cataract surgery and its preparation safer, and helps reduce how often an unsuitable lens is selected.
• Reliable releases: nightly regression testing makes sure the software behaves exactly as it did the day before.

Facing a similar challenge?

Developing software where safety and regulation leave no room for error? Talk to our software development team.