A tear scope using macroscopic imaging ellipsometry and thermal imaging to measure dynamic lipid layer and aqueous distribution on the eye
Institute Reference: 2-17089
Dry eye syndrome is a chronic condition typically caused by disorders of the ocular tear film. Research shows that lipid layer thickness and distribution uniformity correlate to the evaporation rate of the ocular surface resulting in dry eye. Current clinical diagnoses of evaporative dry eye (EDE) and aqueous tear-deficient dry eye (ADDE) do not provide a sensitive or specific understanding of the structure of the tear lipid layer. High‑resolution optical coherence tomography can measure the aqueous thickness but is expensive. Thus, we require a diagnostic capable of measuring the dynamic lipid layer distribution as well as an inexpensive means to measure the aqueous thickness on the ocular surface to accurately diagnose dry eye and differentiate between EDE and ADDE.
Ellipsometry is a non-destructive and contactless method to investigate the properties of thin film coatings and bare surfaces by measuring the change in the polarization state-of-light after reflection from the coating or surface. Imaging ellipsometry uses a camera as a detector of the reflected light, quantifying and visualizing the thickness distribution of thin transparent layers on substrates.
The researchers have adapted this technology to enable a macroscopic imaging ellipsometer which offers a larger field of view than traditional imaging ellipsometers giving a holistic view of the tear lipid layer. This technology is a novel extension of existing imaging ellipsometers that have a macroscopic field of view of tens of mm, compared to conventional imaging ellipsometers which cover about several hundred microns.
Dual-wavelength thermal imaging can map the thickness of the aqueous layer over the entire cornea non-invasively in real‑time. Based on long-wavelength infra-red room temperature bolometer cameras, this imaging modality can work with the imaging ellipsometer to simultaneously map lipid and aqueous thickness of the ocular surface. Because the cameras are used commercially for environmental sensing they are very inexpensive.
The macroscopic imaging ellipsometer retrieves both the thickness and refraction index of a film covering a flat or curved surface. This technology also provides a deeper insight into the tear film break-up process which would aid in clinically distinguishing between ADDE and EDE for improved dry eye syndrome diagnosis and treatment testing. Dual-wavelength thermal imaging provides a real-time map of the aqueous layer thickness.
This technology has broad applications across several fields. In ophthalmology and optometry, it can provide advanced diagnostic techniques to evaluate and monitor eye health with precision. It can also play a crucial role in pharmaceutical research and development, particularly in the creation of innovative treatments for dry eye syndrome.
Beyond clinical settings, the system can be used in optical metrology testing, enabling accurate analysis of thin films essential for various scientific and industrial applications. Additionally, it is a valuable tool for academic research, offering insights into the mechanisms of ocular surface health and diseases, thereby advancing understanding of these critical areas.
The university seeks to license this technology exclusively.