This clinical trial aims to evaluate the use of a contactless and non-invasive technique to measure the properties of the skin's microcirculation and its regulatory functions in both healthy individuals and patients with microvascular disease associated with type 1 diabetes. It is hoped that the study results will lead to the development of a useful method for detecting diabetic complications at an early stage, thereby enabling treatment and preventive measures before the onset of severe microangiopathy.

This study will employ investigational devices to evaluate microvascular function and correlate it to degree of microangiopathy in persons with diabetes type 1 and healthy controls.

The investigational device, TCI P4, is a novel, contactless, non-invasive, non-CE marked, class IIa Spatial Frequency Domain Imaging (SFDI) system. The device utilizes an LED light projector to cast patterned, multi-wavelength light onto the skin while multiple cameras capture narrow-band reflections. This method yields two-dimensional data on skin structure and molecular composition (including hemoglobin, oxygen, and water). Established comparators such as laser speckle contrast imaging (LSCI) and the EPOS system are employed to benchmark device performance and validate measurements.

Inclusion Criteria:

• Diabetes mellitus type 1.
• Cohort specific inclusion criteria apply, please review 'groups' section.

Exclusion Criteria:

• Patients unable to understand patient information due to cognitive impairment.
• Patients unable to understand patient information due to language barriers.
• Ongoing acute infection disease or inflammatory condition.
• Pregnant or breast-feeding women.
• Patients with damaged and/or scarred tissue in the areas of interest for the investigational or comparator devices.

Outpatient at Danderyd Hospital Diabetes Clinic