Eye Floaters and COVID: Key Points to Consider

Visual disturbances like eye floaters have been reported following COVID-19 infection. While these drifting shapes are common with aging, their occurrence in relation to the virus has raised concerns about potential underlying mechanisms. Understanding whether COVID-19 contributes to or exacerbates eye floaters is important for those experiencing new or worsening symptoms.

Ocular Responses In COVID Cases

The impact of COVID-19 on ocular health has gained attention, with reports of various eye-related symptoms emerging throughout the pandemic. While respiratory complications have dominated discussions, ophthalmic manifestations such as conjunctivitis and visual disturbances have also been documented. Among these, the appearance or worsening of eye floaters has prompted investigations into whether SARS-CoV-2 affects the vitreous body or retinal structures.

Several studies have highlighted ocular symptoms in COVID-19 patients, with conjunctival congestion being one of the more frequently reported issues. A study published in JAMA Ophthalmology found that approximately 31.6% of hospitalized COVID-19 patients exhibited redness, excessive tearing, and discomfort. While these symptoms are often attributed to viral conjunctivitis, more persistent visual disturbances, such as floaters, suggest involvement of deeper ocular structures. The virus’s ability to bind to angiotensin-converting enzyme 2 (ACE2) receptors, present in the retina and vascular endothelium, raises the possibility of localized inflammation or microvascular changes contributing to these effects.

Retinal findings in COVID-19 cases provide further insight. A study in The Lancet reported retinal microvascular abnormalities, including cotton wool spots and microhemorrhages, in recovering patients. These findings suggest that SARS-CoV-2 may induce vascular dysfunction, leading to transient or lasting changes in ocular circulation. Disruptions in retinal blood flow could contribute to the perception of floaters, particularly if small hemorrhages or inflammatory byproducts enter the vitreous humor. Optical coherence tomography (OCT) imaging has also revealed hyperreflective lesions in the inner retinal layers of some COVID-19 patients, supporting the notion that viral or immune-mediated effects extend beyond the ocular surface.

Mechanisms Behind Eye Floaters

Eye floaters result from disruptions within the vitreous humor, the gel-like substance between the lens and the retina. Composed of water, collagen fibers, and hyaluronic acid, this structure maintains ocular shape and allows light to reach the retina. Over time, structural changes can lead to the aggregation of collagen fibrils, forming opaque strands that cast shadows on the retina, appearing as drifting specks or cobweb-like shapes. While age-related degeneration is the most common cause, trauma, systemic diseases, and vascular irregularities can also contribute.

The vitreous undergoes syneresis, in which its gel-like consistency gradually liquefies. This process causes collagen fibrils to separate from the surrounding matrix and coalesce into larger aggregates. As these condensed fibers move, they interfere with the passage of light, resulting in floaters. Posterior vitreous detachment (PVD), often associated with aging, occurs when the vitreous separates from the retinal surface. This detachment can create additional floaters, sometimes accompanied by flashes of light due to mechanical stimulation of retinal photoreceptors. While PVD is usually benign, it increases the risk of retinal tears or detachment if traction forces disrupt the underlying tissue.

Structural modifications in the vitreous can also result from pathological processes. In diabetic retinopathy, prolonged hyperglycemia damages retinal capillaries, leading to microaneurysms and hemorrhages. If blood leaks into the vitreous, it can form transient or persistent opacities that appear as floaters. Similarly, hypertensive retinopathy can induce vascular stress, resulting in retinal microbleeds. Myopic individuals face a higher risk of vitreous degeneration due to the elongation of the eyeball, which alters mechanical stability and predisposes it to early liquefaction and detachment. These vulnerabilities increase the likelihood of floater formation, particularly in cases of high myopia where retinal thinning exacerbates the effects.

Inflammatory Reactions In Recovery

As individuals recover from COVID-19, lingering inflammation can affect multiple organ systems, including the eyes. The post-viral phase often involves a prolonged resolution of inflammatory processes, which may influence ocular tissues and contribute to visual disturbances. Inflammation within the eye, particularly in the vitreous body or retinal structures, can reduce the optical clarity of the vitreous humor, leading to an increased perception of floaters.

Ocular inflammation following viral infections is not uncommon. In COVID-19 cases, systemic inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) have been found to remain elevated in some patients weeks after recovery. These markers are associated with vascular permeability and tissue edema, which may extend to retinal capillaries and the vitreous chamber. If inflammatory byproducts, such as fibrin or immune cell debris, accumulate within the vitreous, they can manifest as transient floaters until the inflammatory response fully subsides. In some cases, low-grade inflammation may persist, prolonging visual symptoms.

The persistence of ocular inflammation has been observed in other viral infections, such as cytomegalovirus and Epstein-Barr virus, where post-viral uveitis can lead to prolonged visual disturbances. While COVID-19 does not typically cause severe ocular inflammation, reports of post-viral uveitis and retinal vasculitis suggest localized immune activation could contribute to vitreous opacities. Individuals with preexisting inflammatory eye conditions, such as uveitis or diabetic retinopathy, may be particularly susceptible to prolonged effects, exacerbating floater-related symptoms.

Differentiating Floaters From Other Visual Changes

Visual disturbances take many forms, and distinguishing eye floaters from other anomalies is important. Unlike distortions affecting overall clarity or color perception, floaters appear as discrete, shadowy shapes that drift within the field of vision. Their movement is a defining characteristic—changing position with eye motion and often becoming more noticeable against bright backgrounds. This differs from visual snow, which presents as a persistent static-like pattern, or from photopsia, which manifests as brief flashes of light linked to retinal traction.

While floaters are generally harmless, a sudden increase in their number, especially when accompanied by light flashes or a curtain-like shadow in peripheral vision, may indicate retinal detachment. This serious condition occurs when the retina separates from the underlying tissue, disrupting visual processing. Unlike benign floaters, which remain relatively stable or increase gradually, retinal detachment symptoms escalate quickly and require immediate medical attention. Similarly, visual distortions such as wavy or missing areas in central vision may point to macular conditions like age-related macular degeneration or central serous retinopathy, which affect retinal layers responsible for sharp detail perception.