title: Ultrasound-based quantification of vitreous floaters correlates with contrast sensitivity and quality of life.
abstract: OBJECTIVE
  Clinical evaluation of floaters lacks quantitative assessment of vitreous structure. This study used quantitative ultrasound (QUS) to measure vitreous opacities. Since floaters reduce contrast sensitivity (CS) and quality of life (Visual Function Questionnaire [VFQ]), it is hypothesized that QUS will correlate with CS and VFQ in patients with floaters.
  
  
  METHODS
  Twenty-two eyes (22 subjects; age = 57 ± 19 years) with floaters were evaluated with Freiburg acuity contrast testing (FrACT; %Weber) and VFQ. Ultrasonography used a customized probe (15-MHz center frequency, 20-mm focal length, 7-mm aperture) with longitudinal and transverse scans taken in primary gaze and a horizontal longitudinal scan through premacular vitreous in temporal gaze. Each scan set had 100 frames of log-compressed envelope data. Within each frame, two regions of interest (ROIs) were analyzed (whole-central and posterior vitreous) to yield three parameters (energy, E; mean amplitude, M; and percentage of vitreous filled by echodensities, P50) averaged over the entire 100-frame dataset. Statistical analyses evaluated E, M, and P50 correlations with CS and VFQ.
  
  
  RESULTS
  Contrast sensitivity ranged from 1.19%W (normal) to 5.59%W. All QUS parameters in two scan positions within the whole-central ROI correlated with CS (R > 0.67, P < 0.001). P50 in the nasal longitudinal position had R = 0.867 (P < 0.001). Correlations with VFQ ranged from R = 0.52 (P < 0.013) to R = 0.65 (P < 0.001).
  
  
  CONCLUSIONS
  Quantitative ultrasound provides quantitative measures of vitreous echodensity that correlate with CS and VFQ, providing objective assessment of vitreous structure underlying the functional disturbances induced by floaters, useful to quantify vitreous disease severity and the response to therapy.
authors.affiliation: F. L. Lizzi Center for Biomedical Engineering, Riverside Research, New York, New York, United States.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Mamou
authors.affiliation: VMR Institute for Vitreous Macula Retina, Huntington Beach, California, United States Doheny Eye Institute/UCLA, Los Angeles, California, United States.
authors.forename: Christianne A
authors.initials: CA
authors.lastname: Wa
authors.affiliation: VMR Institute for Vitreous Macula Retina, Huntington Beach, California, United States Doheny Eye Institute/UCLA, Los Angeles, California, United States.
authors.forename: Kenneth M P
authors.initials: KM
authors.lastname: Yee
authors.affiliation: F. L. Lizzi Center for Biomedical Engineering, Riverside Research, New York, New York, United States Department of Ophthalmology, Columbia College of Physicians & Surgeons, New York, New York, United States.
authors.forename: Ronald H
authors.initials: RH
authors.lastname: Silverman
authors.affiliation: F. L. Lizzi Center for Biomedical Engineering, Riverside Research, New York, New York, United States.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Ketterling
authors.affiliation: Doheny Eye Institute/UCLA, Los Angeles, California, United States.
authors.forename: Alfredo A
authors.initials: AA
authors.lastname: Sadun
authors.affiliation: VMR Institute for Vitreous Macula Retina, Huntington Beach, California, United States.
authors.forename: J
authors.initials: J
authors.lastname: Sebag
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015350:Contrast Sensitivity / Q000502:physiology*; D005128:Eye Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life / Q000523:psychology*; D013223:Statistics as Topic; D011795:Surveys and Questionnaires; D014463:Ultrasonography; D014792:Visual Acuity / Q000502:physiology; D014822:Vitreous Body / Q000000981:diagnostic imaging* / Q000503:physiopathology
keywords: contrast sensitivity; floaters; quality of life; ultrasonography; vitreous