What causes blurry vision in hypoglycemia (low blood glucose)?

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Last updated: April 16, 2025View editorial policy

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From the FDA Drug Label

Symptoms of low blood sugar may include: ... blurred vision ... The FDA drug label states that blurred vision is a symptom of low blood sugar (hypoglycemia), which can occur when using insulin, such as Levemir 1.

  • Low blood sugar can cause a range of symptoms, including blurred vision, and it is essential to treat it promptly to avoid severe consequences.
  • The exact mechanism of how low blood sugar causes blurry vision is not explicitly stated in the drug label, but it is likely related to the effects of hypoglycemia on the body's physiological processes.

From the Research

Blurry vision during low blood glucose (hypoglycemia) occurs because the brain and eyes depend heavily on glucose for proper functioning, and when blood sugar drops, the retina and visual cortex receive inadequate energy to function properly. When blood sugar drops below normal levels (typically under 70 mg/dL), the retina and visual cortex receive inadequate energy to function properly. The retina, which contains photoreceptors that convert light into neural signals, requires constant glucose to maintain its high metabolic activity. During hypoglycemia, these cells cannot process visual information efficiently, leading to impaired signal transmission to the brain. Additionally, the brain's visual processing centers themselves become energy-deprived, further compromising visual acuity. This temporary visual disturbance typically resolves once blood glucose levels are restored to normal range. If experiencing hypoglycemia with blurry vision, consuming 15-20 grams of fast-acting carbohydrates (like glucose tablets, fruit juice, or regular soda) can quickly raise blood sugar levels and resolve visual symptoms, as suggested by recent studies on hypoglycemia management 2. For diabetic patients, regular blood glucose monitoring and maintaining levels within target ranges can prevent these episodes, and the use of continuous glucose monitoring (CGM) can help identify glycemic excursions and actionable glucose patterns to improve therapeutic decision-making by clinicians 3.

Some key points to consider in the management of hypoglycemia and prevention of blurry vision include:

  • Regular blood glucose monitoring to maintain levels within target ranges
  • Consuming 15-20 grams of fast-acting carbohydrates to quickly raise blood sugar levels during hypoglycemia
  • Using CGM to identify glycemic excursions and actionable glucose patterns
  • Being aware of the potential dangers of hypoglycemia and taking steps to prevent it, such as patient education and regular review with healthcare professionals 4.

It is also important to note that hypoglycemia is a common complication in patients with diabetes, mainly in those treated with insulin, sulfonylurea, or glinide, and that impairments in counterregulatory responses and hypoglycemia unawareness constitute the main risk factors for severe hypoglycemia 5.

Overall, the management of hypoglycemia and prevention of blurry vision requires a comprehensive approach that includes regular blood glucose monitoring, patient education, and the use of CGM to identify glycemic excursions and actionable glucose patterns.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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