News from medicine and humanities concerning eye floaters and entoptic phenomena.
Survey: 76% of people see floaters
Webb, Blake F. et al. (2013): Prevalence of vitreous floaters in a community sample of smartphone users. In: International Journal of Ophthalmology 6, Nr. 3: 402-405.
Ophthalmologists know from their clinical practice that eye floaters are a common and usually harmless phenomenon. So far, however, there were no statistics to make statements about the prevalence of floaters in society beyond the clinical environment. A research team from the U.S. has investigated this issue.
First of all, two types of vitreous floaters are distinguished by their causes: floaters through 1) introduction of exogenous material during hemorrhage or inflammation, and 2) degenerative changes in the collagen-containing molecular vitreous fibrils. However, this distinction is not relevant to the authors, since the appearance of both types of floaters is described as “spots, shadows, cobwebs, and other assorted shapes that seem to move about in the field of vision.” Then we are told that today’s treatments are usually conservative (“reassurance of the patient”), that most floaters are benign and that the causes are largely unknown.
To obtain data about the prevalence of floaters in the general population, the authors have launched a survey in the form of an app for Android smartphones. In it, participants provided demographic and health-related information. Then they were asked to answer the following question: „Have you ever noticed things that look like specks, squiggly lines, or dark spots that seem to float around in your vision? They are usually noticed when squinting and looking at a bright background like the blue sky or a bright, white computer screen.” On a scale of 1 to 5, the participants had to specify how disturbing their dots and strands were to them. 1098 people especially from the U.S., Australia, Israel and the UK took part, 603 complete responses were evaluated. The authors explicitly excluded participants with diseases such as diabetes and glaucoma, as well as those with eye injuries and LASIK treatment. The survey found that 76% of respondents perceived floaters. This value was not
significantly affected by age, race, gender and eye color. 33% of respondents reported that the floaters were moderate to severe. Myopes and hyperopes had the same prevalence of floaters, but were several times more likely to report moderate to severe floaters.
The survey found that 76% of respondents perceived floaters and 33% of respondents reported that the floaters were moderate to severe. Source: (Picture)
76 % of people see MV. This should not be taken literally: On the one hand, only certain groups of people participated in this survey, especially young white men with smartphone access, who were interested in, and therefore searching for, eye health-related topics. We know little or nothing about the prevalence of floaters in the elderly, children and teenagers, people without smartphones, and people from non-Western societies – which, after all, represent the majority of the total world population. On the other hand, it can be assumed that this is another scientific study in which shining structure floaters get shuffled together with actual vitreous opacities. The authors describe floaters as “spots, shadows, cobwebs, and other assorted shapes that seem to move about in the field of vision” and are seen “when squinting and looking at a bright background like the blue sky or a bright, white computer screen.” Superficially, this description fits not only vitreous opacities, but also
shining structure floaters I assume that a large part of the 76% see shining structure floaters, especially – but not exclusively – those who do not or hardly feel disturbed by their floaters. The group of people who feel disturbed by floaters on a moderate to severe degree, is with one third surprisingly high. But this number, too, should not be overestimated. For it can also be explained by the fact that the survey was completed especially by those people who are interested in the health of their eyes. These people are no doubt more sensitive to visual impairments than others.
95% of respondents are under 50 years old, and no increasing occurrences of floaters could be detected with advancing age. While this does not tell us anything about floaters in the elderly, nor in children or youth (participants had to be 18 years old to take part in the survey). But it should confute the claim that floaters are largely an age-related phenomenon – at last! In addition, the study’s results refute another floater myth, namely that there is a positive relationship between seeing floaters and myopia. This is only partially true. The authors have shown that near-sighted people see as much floaters as normal-sighted and as far-sighted people. This also rules out the association of floaters and posterior vitreous detachment, which was a convenient attempt to explain floaters because it often and early occurs in myopes. While myopes tend to report more moderate and severe floaters than normal-sighted people, this is also true of hyperopes. Myopes and hyperopes are more
sensitive to floaters than others. I suggest that the reason for this must be beyond the physiology of the eye. Maybe it’s just that people with visual impairment become aware of eye floaters more easily, because the near or far of the material world appears blurry. And that they rather feel disturbed by their floaters, because they intuitively and unconsciously associate the dots and strings with their poor eyesight, or with their inability to properly see the world.