Researchers have developed a new non-invasive imaging technique to improve the treatment and diagnosis for dry eye disease which causes irritation and blurred vision. The study, published in the journal Applied Optics, noted that up to 60 per cent of patient visits to the eye doctor could be due to dry eye.
The researchers, including those from The Optical Society in the US, mentioned that the eye disease occurred when there was instability in the inner layer of the tear film that protects the outside of the eye.
Since most cases of the disease are diagnosed using patient questionnaires, the researchers said that the process was subjective, and could not be used to identify the cause of the disease. Until now, the researchers said, objective methods for examining the tear film was invasive and could not track rapid changing dynamics, that altered with every blink of the eyes.
"Our Tear Film Imager is the first device that can be used in the ophthalmology or optometry setting to image the tear film and distinguish its inner layers with nanometer resolution," said Yoel Arieli, lead author of the study from AdOM Advanced Optical Methods Ltd. in Israel.
The new instrument uses an eye-safe halogen light to illuminate the eye, and then analyses the full spectrum of light reflection happening over time and space, the study noted. The measurements, completed automatically in just 40 seconds, are used to reconstruct the structures found in the front of the eye, allowing ophthalmologists to accurately measure the tear film inner layers, particularly the aqueous sublayer.
The researchers said that this sublayer played an important role in dry eye, but had been difficult to analyse with other methods. "The broadband illumination source and fine details available from spectral analysis provide nanometer-level insight into subtle changes in each tear film layer and sublayer," said Arieli.
The research team tested the instrument's ability to take measurements on the human eye while the patient was blinking without any interference. "The device worked impressively and presents no risk because it is non-invasive and uses a simple light source," said Arieli.
The instrument measured the tear film consistently including blinks every few seconds, and the measurements correlated well with other partially invasive, commonly used dry eye diagnostic techniques, the study noted.