You can perceive eye floaters even with your eyelids closed. This visual phenomenon occurs due to light interacting with the eye’s internal structures, casting shadows onto the retina. While often benign, understanding floaters and when to seek professional advice is important for eye health.
What Are Eye Floaters?
Eye floaters are small specks, threads, or cobweb-like shapes that drift across your field of vision. They originate from within the eye. Floaters become noticeable against a plain, bright background, such as a clear sky or a white wall.
These visual disturbances are shadows cast on the retina by tiny debris suspended within the vitreous humor. The vitreous humor is a clear, gel-like substance that fills the space between the lens and the retina. As a natural part of aging, the collagen fibers in the vitreous can clump or liquefy, creating these visible opacities.
The Mechanism of Seeing Floaters With Closed Eyes
You can see floaters with closed eyes because eyelids are not entirely opaque; some ambient light can penetrate them. Eyelid skin is thin and allows light transmission, particularly red light. This internal illumination, even if dim, is sufficient to cast shadows from floaters onto the retina.
These shadows are then interpreted by the brain as moving shapes. This phenomenon is an example of entoptic phenomena, visual effects originating within the eye. Floaters, suspended within the vitreous, move as the eye moves. When the eye stops, they continue to drift due to inertia before settling.
The visibility of floaters with closed eyes can be more pronounced in brightly lit environments, where more light filters through the eyelids. The slight movement of the eye even when closed, or even the eye’s natural internal light, can shift these vitreous opacities, allowing their shadows to be perceived. This constant presence means that even in perceived darkness, the internal structures of the eye can still create visual sensations.
When to Consult an Eye Care Professional
While most eye floaters are harmless and a normal part of aging, certain changes warrant immediate attention from an eye care professional. A sudden increase in floaters, especially if accompanied by flashes of light (photopsia), should prompt an urgent eye examination. These symptoms can indicate a serious underlying condition such as a retinal tear or retinal detachment.
Other concerning symptoms include a sudden appearance of new floaters, a gray curtain or shadow blocking part of your vision, or a loss of peripheral vision. These signs suggest the vitreous gel may be pulling on the retina with enough force to cause a tear, which could lead to a retinal detachment if left untreated. Timely diagnosis and treatment are crucial to prevent permanent vision loss.