Subjective Grading of Subclinical Vitreous Floaters

PURPOSE: This study aimed to objectively grade the perception of subclinical floaters in an asymptomatic cohort. DESIGN: A prospective observational cohort study. METHODS: One hundred eighty-two volunteers (49 men, 133 women) with ages ranging from 17.7 to 78.6 years were recruited for floater assessment. Participants were assessed by a light box and by vitreoscope, after which they graded the floaters using a graphic classification system. They also completed a questionnaire to estimate the impact of floaters on daily life. In addition, biometric and refractive data were documented for all participants. RESULTS: Using the light box method, 67.6% of participants reported seeing transparent floaters, which increased to 84.1% when using the vitreoscope. Opaque floaters were seen by 15.9% (light box) and 6.5% (vitreoscope). Reported levels of floater discomfort varied between participants, with 80.2% of participants reporting no discomfort and 6.6% reporting moderate to manifest discomfort. The perceived discomfort was weakly correlated with the amount of visualized floaters (light box: Pearson r = 0.323, P < 0.001; vitreoscope: r = 0.174, P < 0.001). Both floater perception and discomfort increased with age (r = 0.203, P = 0.006; r = 0.194, P = 0.009, respectively), although neither changed with axial length or refraction (P = 0.131, P = 0.070, respectively). CONCLUSIONS: The light box and the vitreoscope demonstrate that subclinical floaters are very common, even in nonsymptomatic subjects. The amount of perceived floaters in this cohort correlates only weakly with floater-related discomfort.