Mobile vitreous opacities on ocular ultrasonography are not always pathologic: a cross-sectional survey in an asymptomatic population.

BACKGROUND Ultrasonography is often used in the evaluation of patients with ocular concerns; however, several pathologic conditions and even some age-related changes can have similar sonographic appearances. One approach that clinicians use is to assume that unilateral findings visible at normal gain are acute, whereas bilateral findings requiring high gain are chronic, especially in the elderly population. To date, no studies have systematically evaluated this assumption. OBJECTIVES The objectives are to determine the prevalence of monocular and binocular mobile vitreous opacities (MVOs) in the vitreous chamber in an asymptomatic population at normal and high gain levels and to determine its prevalence with higher age stratifications. METHODS We conducted a cross-sectional survey using 2-dimensional ultrasonography with a high-frequency transducer of 105 asymptomatic subjects aged 20-89 years and evaluated each subject's eyes for the presence of MVOs at both normal and high gain levels in progressive age stratifications. RESULTS Ultrasonographic scans were obtained on 105 subjects. At normal gain levels, MVO was present in only 1 subject (0.95%; 95% confidence interval, 0.0%-5.0%). At high gain levels, MVO was present in 28.6% (30/105) of subjects. Of the subjects with MVO at high gain, 60% (18/30) had unilateral MVO. Mobile vitreous opacity was found more frequently with advancing age, being present in 23 subjects older than 59 years, compared with 7 subjects 59 years and younger (51.1% vs 11.7%, P < .001). CONCLUSIONS Mobile vitreous opacity in the vitreous chamber visualized at high gain levels is relatively common and may not be pathologic, even if unilateral and occurring at a relatively young age.