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Justin Nguyen, Kenneth M.P. Yee, Jeannie Nguyen-Cuu, J Sebag; Vitreous Structure and Visual Function in Myopic Vitreopathy and Posterior Vitreous Detachment. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5485. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate vitreous structure and visual function in myopic eyes with and without posterior vitreous detachment (PVD), since it is not known whether myopic vitreopathy is associated with reduced contrast sensitivity (CS) compared to emmetropic controls, and whether PVD further lowers CS. Increased vitreous echodensity is hypothesized to correlate with reduced CS in each case.
Vitreous structure was assessed by quantitative ultrasonography (QUS), as previously described (IOVS 56:1611–7, 2015). Visual function was evaluated by visual acuity (VA, Snellen decimal) and CS using the Freiburg Acuity Contrast Test (Weber Index, %W: lower score = better CS). 35 myopes (mean age = 52.5 ± 14.1 yrs; average degree of myopia = -5.2 ± 2.9 D; 17 with -1 to -5D, 18 with ≥ -6D) with clinically significant vitreous floaters were compared to 38 age-matched controls (mean age = 51.24 ± 14.6 years; P=0.7092). Myopes without PVD (n=10; age = 36.6 ± 13.1 yrs) were compared to younger controls (N=23; age=43 ± 13.1 yrs; P=0.21). Myopes with PVD (N=25; age = 58.9 ± 8.3 yrs) were compared to older controls (N=15; age = 60.9 ± 7.5 yrs; P=0.45).
Average VA of controls was 0.78 ± 0.16 with no difference between young controls (0.81 ± 0.15) vs. older controls (0.72 ± 0.17; P = 0.095). VA in myopic vitreopathy eyes without PVD (0.68 ± 0.15) was significantly worse than controls (P = 0.0076). There was no significant difference in VA between myopes with (0.66 ± 0.17) and without (0.73 ± 0.05) PVD (P=0.22).CS in myopes without PVD (3.31 ± 0.9 %W) was significantly worse than young controls (2.04 ± 0.68%W; P=0.0001). CS in myopes with PVD (4.90 ± 1.75%W) was significantly worse than older controls (2.35 ± 0.63; P<0.0001) and myopes without PVD (3.31 ± 0.9 %W; P<0.01).QUS backscatter in the pre-macular vitreous was significantly higher in myopic eyes with PVD (911.36 ± 383.57 AU) compared to myopic eyes without PVD (532.15 ± 80.51 AU; P=0.034).
Myopic eyes with vitreous floaters have worse VA and CS than age-matched controls. Myopes with PVD have worse CS and QUS than eyes with only myopic vitreopathy. These results suggest that myopic vitreopathy diminishes CS via increased internal vitreous collagen aggregation as reflected by vitreous echodensity. PVD induces even greater premacular vitreous echodensity, further lowering CS probably due to light scattering by the detached posterior vitreous cortex.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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