The Tear Film Imager quantifies the dynamic properties of the tear film inner layers (muco-aqueous layer and lipid layer) using a single non-contact measurement. The Tear Film Imager’s measurement features the natural behavior of the tears while allowing the patient to blink naturally.
The Tear Film Imager uses spectral interference technology to measure the thickness of the tear film inner layers over time. The device displays a live video of the corneal surface on a large screen with a large field of view (6 mm diameter) with a thickness map of the lipid layer’s uniformity.
The thickness of the tear film is several micrometers, and its typical lipid inner-layer is very thin, only 20-100 nanometers [King-Smith 2010]. The Tear Film Imager provides depth resolution down to a few nanometers. As a reference, spectral-domain OCT, the well-known gold standard as diagnostic for the back of the eye, has a practical resolution of about 2,000-5,000 nanometers - the same order of magnitude of the entire tear film.
The Tear Film Imager’s technology stands on 3 pillars: accurate reflectometry that analyzes the interference to get the thickness of the tear film inner layers, full-field imaging that provides a quantification of the spatial non-uniformities, and proprietary algorithms to resolve the tear inner layers thickness and their dynamic changes.
The technology is covered by many AdOM patents that are comprised into the proprietary TFI design.
The TFI measures and can report the following representative values whilst the patient's eyes may blink naturally:
Muco-Aqueous layer thickness parameters – the TFI provides Muco-Aqueous layer thickness (MALT) measurements with nanometers resolution:
Dynamics of the MALT over time
Muco-Aqueous layer thickness change rate (MALTR)
Lipid layer thickness parameters – the TFI provides the lipid layer thickness (LLT) measurements with nanometers resolution:
Dynamics of the lipid layer thickness (LLT) over time
LLT map over large field of view
Lipid breakup time (LBUT)
Lipid map uniformity (LMU)
Mean Blink frequency is evaluated by the Interblink interval (IBI) measured in seconds and is the inverse of the blink rate.
This advanced TFI technology was developed to offer a range of non-invasive measurements of all tear film sublayers to eye care providers in their assessment of patients.
As Prof. Trokel, a leading cornea specialist states “It [The TFI is] perhaps as significant as Hans Goldmann Applanation Tonometer in the later 30s”.