It is a common experience for individuals to notice changes in their vision, such as blurriness, when they are feeling unwell. This temporary visual disturbance stems from various factors, including direct physiological responses to illness and medication side effects.
Common Illness-Related Causes
Dehydration, a frequent companion to many illnesses, can significantly affect eye function. When the body lacks sufficient fluids, tear production may decrease, leading to dry eyes. Dryness on the ocular surface can cause irritation and temporary blurring of vision.
Elevated body temperatures, such as those experienced during a fever, can contribute to visual disturbances. A fever can cause blood vessels in the eyes to dilate, potentially leading to discomfort or a feeling of pressure that temporarily impacts visual clarity. The general systemic stress associated with fever can also affect the delicate balance required for sharp vision.
Medications commonly used to alleviate cold and flu symptoms, such as antihistamines and decongestants, can have ocular side effects. Antihistamines, for instance, can reduce tear production, leading to dry eyes and blurriness. Decongestants may affect blood vessels in the eyes, causing temporary visual changes.
General fatigue and malaise, hallmarks of many illnesses, can lead to increased eye strain. When the body is fighting an infection, energy reserves are diverted, making it harder for the eyes to focus effectively and maintain visual acuity. This can result in tired eyes and a temporary reduction in visual sharpness.
Inflammation and pressure from congested sinuses can directly impact the eyes. Sinus cavities are located close to the eyes, and swelling or pressure in these areas can press on nerves or blood vessels supplying the eyes, leading to a sensation of blurriness or discomfort.
Systemic Effects and Underlying Health
Illness can sometimes trigger fluctuations in blood sugar levels, which may manifest as temporary blurry vision. For individuals with diabetes, an infection can make blood sugar control more challenging, leading to either hyperglycemia (high blood sugar) or hypoglycemia (low blood sugar), both of which can cause the lens of the eye to swell and alter its refractive power. Even in non-diabetic individuals, severe illness can induce temporary changes in blood glucose regulation, potentially affecting vision.
Changes in blood pressure, whether a temporary increase or decrease, can also influence ocular health and vision during an illness. Significant shifts in blood pressure can affect the blood supply to the eyes, potentially leading to transient visual disturbances. This effect is usually temporary and resolves as blood pressure stabilizes.
Systemic inflammation or certain infections that spread beyond the immediate eye area can also indirectly impact vision. Widespread bodily inflammation can affect various physiological processes, including those that support clear vision. Illness or stress can sometimes act as triggers for migraines, which often include visual disturbances known as auras. These auras can involve temporary blurry vision, shimmering lights, or blind spots before or during a headache phase.
When to Seek Medical Advice
While temporary blurry vision during illness is common, certain symptoms warrant prompt medical evaluation. Sudden or severe onset of blurry vision, especially if it occurs rapidly or significantly impairs daily activities, should be reported to a healthcare professional without delay. This could indicate a more serious underlying issue.
Vision loss in only one eye is a particularly concerning symptom that requires immediate medical attention. Similarly, if blurry vision is accompanied by eye pain or noticeable redness, these combined symptoms suggest a need for professional assessment to rule out an infection or other ocular condition. Experiencing double vision, where a single object appears as two, is another symptom that necessitates medical consultation.
Sensitivity to light, also known as photophobia, when it occurs alongside blurry vision, can be a sign of certain eye conditions or systemic issues. Additionally, if blurry vision persists even after the primary illness has resolved or if it progressively worsens, it is important to seek medical advice. Blurry vision accompanied by neurological symptoms such as severe headache, numbness, weakness in limbs, or confusion, requires urgent medical care as these could indicate a more serious neurological event.
Managing Blurry Vision During Illness
For temporary blurry vision related to common illnesses, several self-care measures can provide relief. Adequate rest is paramount, as it allows the body to conserve energy and focus on recovery, which can indirectly help alleviate eye strain and fatigue contributing to blurry vision. Prioritizing sleep supports overall healing processes.
Staying well-hydrated by drinking plenty of fluids is also beneficial. Proper hydration supports tear production and helps maintain the overall fluid balance in the body, reducing the likelihood of dehydration-induced blurry vision.
Limiting screen time and avoiding prolonged reading can reduce eye strain when feeling unwell. Giving the eyes a break can prevent exacerbating temporary visual issues.
Over-the-counter artificial tears can be used to lubricate dry eyes, which are a common cause of blurriness during illness. These drops can help restore the eye’s natural moisture balance.
Ultimately, effectively managing the symptoms of the underlying illness, such as reducing fever or clearing nasal congestion, often leads to the resolution of associated blurry vision. Addressing the root cause typically brings visual clarity back to normal.