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Azin Abazari, Harbans Dhadwal, John Wittpenn; In Vivo Observational Clinical Study of Lens Transparency using the Vision Index Pen.. Invest. Ophthalmol. Vis. Sci. 2019;60(9):3166. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Detection of early aging changes in crystalline lens can be useful in screening the subjects, whom may benefit from early therapeutic interventions. The Vision Index Pen (VIP) diagnostic device provides an objective measure of the aggregated state of the crystallins in the lens. Our goals were to establish the clinical utility of the VIP, designed to measure in vivo dynamic light scattering from the crystalline lens, in detection of early cataract or loss of accommodation, and show reproducibility through trials at two independent sites.
157 volunteers in different age groups were participated in two independently operated observational clinical studies. All subjects underwent detailed eye exam and measurement of the intensity correlation of the backscattered light from the lens by VIP.
Intensity correlation of the backscattered laser light is a function of the dynamic behavior of the structural proteins in the human lens. Temporal fluctuations on a time scale ranging from 25 ns to several seconds are captured in a single measurement. The faster time scales correspond to the motion of small molecular constituents such as crystallins, while longer times are associated with the presence of aggregated clusters. Over the course of normal aging, aggregation of crystallins leads to cataract formation and loss of accommodation. The VPI device can track these molecular changes in the lens long before they become clinically observable. The aggregated state of the lens is expressed by the Lens Crystallin Index (LCX), which is extracted from the in vivo measured autocorrelation of the backscattered laser light. Figure 1 shows the observed LCX changes with aging in our two study sites. An expanded view shows that the LCX value changes significantly in the age range of 35 to 55 (Fig-2)
In vivo dynamic light scattering measurement is helpful in identifying patients who can potentially benefit from early interventions to slow the aging process of the lens.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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