Abstract

Purpose : Vitreous opacities cause floaters that impact vision by degrading Contrast Sensitivity (CS), known as vision degrading myodesopsia (VDM; https://doi.org/10.1016/j.preteyeres.2020.100847). VDM results from alterations in the molecular organization of vitreous in myopia and aging, inducing opacities and posterior vitreous detachment that can impair quality-of-life. It is hypothesized that VDM results from light scattering by vitreous. This work measured straylight from excised human vitreous compared to pre-operative clinical quantitative ultrasonography (QUS), CS, and subjective vision satisfaction (VFQ).

Methods : QUS (15 MHz probe, 23mm focal length, 7-mm aperture; IOVS https://doi.org/10.1167/iovs.14-15414), CS (Freiburg Acuity Contrast Test; https://doi.org/10.1016/j.oret.2018.03.011), and NEI VFQ evaluations were performed in 4 eyes from 4 subjects (age = 56±11 years) who underwent vitrectomy for VDM. Within 36 hours of surgery, wide-angle straylight (up to 6 degrees of the visual field) of the fresh excised vitreous was measured using Optical Integration, an objective technique based on the projection of disks onto the retina and subsequent data analysis (https://doi.org/10.3928/1081597X-20160920-02). Dark field images of the samples were used to quantify the Mean Scatter Index (MSI).

Results : There were correlations between the straylight parameter at 0.5^o and QUS parameters (R=0.97, P=0.03; R=0.963, P=0.037). There were also correlations between Dark Field MSI and CS (R=-0.832, P=0.168) as well as Straylight MSI with subjective visual disturbance (VFQ: R=0.932, P=0.068); only nearly statistically significant due to small number of samples (n=4).

Conclusions : Dark Field MSI and Straylight correlated with clinical quantitative ultrasonography, contrast sensitivity, and subjective visual function. This supports the hypothesis that light scattering is the basis for vision disturbance and negative impact on quality-of-life, although more data is required to obtain additional statistically-significant correlations. This also endorses the use of ultrasonography as a meaningful clinical index of vitreous opacification and its impact on photon transmission through the vitreous body of patients with VDM. Lastly, this data enables us to characterize the scattering properties of vitreous opacities, very valuable in the development of scattering compensation techniques for future non-invasive optical vision correction approaches.

This abstract was presented (poster) at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

If you like it, please share it...00