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Jeannie Nguyen-Cuu, Justin Nguyen, Kenneth M.P. Yee, Jonathan Mamou, Jeffrey Ketterling, J Sebag; Nd:YAG effects on Vitreous in Patients with Vision Degrading Vitreopathy. Invest. Ophthalmol. Vis. Sci. 2018;59(9):6197. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Patients with vitreous floaters that impact vision have an average degradation in contrast sensitivity function (CSF) of 67% (Retina 34:1062-8, 2014), qualifying them for the diagnosis of Vision Degrading Vitreopathy. Nd:YAG lasers are being used to treat patients with vitreous floaters, but a recent pilot study found only 54% subjective improvement in only 53% of patients. The reasons for these limited results are not clear, but lack of diminution of vitreous density and limited improvement in CSF are hypothesized to play a role.
To test this hypothesis, 32 subjects (age = 55 ± 13 years) who previously underwent Nd:YAG treatment for vitreous opacities were evaluated in 2 groups: those who were still sufficiently bothered after Nd:YAG laser treatment to desire vitrectomy (PPV; n=22), and those who were satisfied and elected just follow-up observation (Obs; n=10). Subjective status (VFQ-25; Visual Function Questionnaire), visual acuity (VA; logMAR), CSF (%W; Freiburg Acuity Contrast Test), and quantitative ultrasound (QUS; IOVS 56:1611–7, 2015) were performed.
VFQ-25 scores in those who chose vitrectomy was 66.78±9.82, while those who elected observation scored 85.90 ± 13.36 (p<0.0002). The average CSF in surgery eyes was 4.35 ± 0.59%W, while observation eyes were far better at 2.93 ± 1.63%W (p<0.0006). Vitreous echodensity (E=energy M=mean QUS parameters) was greater in subjects who chose surgery (E = 645.71 ± 210.48; M = 22.92 ± 3.39) than observation eyes (E = 489.24 ± 71.91; M = 18.92 ± 3.38) (p<0.003 and p<0.004, respectively). There was no difference in VA (PPV group = 0.11 ± 0.10; Obs group = 0.07 ± 0.09) (p<0.108).
Despite having undergone Nd:YAG laser treatment for vitreous opacities, dissatisfied patients were found to have 29% worse VFQ-25 scores than satisfied patients. Dissatisfied subjects had 48% worse CSF, probably explaining their worse VFQ-25 indices. Quantitative ultrasound found 24% greater vitreous echodensity in those sufficiently dissatisfied to undergo surgery, explaining the worse CSF in these eyes. Thus, Nd:YAG laser treatments that leave patients dissatisfied probably result from abnormal vitreous echodensity and diminished contrast sensitivity function, resulting in their dissatisfaction with vision and desire to undergo vitrectomy.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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