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  • Writer's pictureAtanas Bogoev M.D. and Maria Cholakova

Can Fasting Affect Your Eyesight?

Fasting captures the curiosity of many researchers studying health secrets. In the context of eye care, we ask the question: Can fasting affect your eyesight or is it just a harmless eating habit? Let's get into the topic. This quest to understand how fasting and eyesight are bound together may reveal many secrets to eye health.

Physiology of Fasting and Eye Health

Fasting is a voluntary abstention from food and drink for predetermined periods. People practice it for a variety of reasons, including religious, spiritual, health, and fitness goals.

While fasting offers potential health benefits, its impact on different bodily systems, including eyesight, is a subject that warrants investigation.

Metabolic Changes During Fasting

Fasting triggers a cascade of metabolic changes within the body. The most noticeable ones are a reduction in blood glucose levels and an increase in insulin sensitivity. These changes lead to a better use of energy reserves - stored fats and glycogen. While we primarily associate the shifts with weight management, they can have wider implications for eye health.

Hormonal Regulation

Fasting triggers hormonal changes extending beyond weight control. Two key hormones of interest are growth hormone and brain-derived neurotrophic factor (BDNF). Growth hormone helps in cell repair and regeneration, which could have protective effects on retinal health. BDNF may also benefit the eyes by promoting neuronal survival and function.

Nutrient Deprivation

Vitamins and antioxidants are crucial for maintaining eye health and preventing age-related eye diseases. And fasting may lead to a temporary deprivation of essential nutrients. The deprivation is generally short-term and manageable. But fasting should strike a balance with a nutritious diet on non-fasting days. That's to prevent any potential deficiencies.

Potential Effects of Fasting on Eyesight

Enhanced Autophagy and Eye Health

One of the intriguing effects of fasting is the activation of autophagy, a cellular "clean-up" process. Autophagy helps remove damaged cellular components, including those within the eyes. By eliminating cellular debris, theoretically, fasting may reduce the risk of eye diseases from old age, resulting from the accumulation of damaged proteins. There's still more need for medical research for conclusive results.

Reduced Oxidative Stress and Inflammation

Oxidative stress and chronic inflammation are key drivers of eye conditions like age-related macular degeneration (AMD) and diabetic retinopathy. In some cases, fasting may help mitigate these factors, thanks to its antioxidant properties and the reduction of inflammatory markers. This suggests fasting, when done right, might play a role in protecting the eyes from these debilitating conditions.

Improved Insulin Sensitivity

For patients with diabetes, maintaining stable blood sugar levels is crucial for preventing diabetic eye complications. Fasting can improve insulin sensitivity, making it easier to manage blood sugar levels. However, we need to acknowledge that fasting should be approached cautiously for individuals with diabetes.

Fasting may offer potential benefits for diabetic eye health under medical supervision. But could worsen the eye problems without any monitoring.

Considerations for Eye Health

Intermittent Fasting

Intermittent fasting, including time-restricted eating and alternate-day fasting, has widespread popularity. These fasting modalities allow for flexible eating patterns while still reaping potential ocular benefits. Please consult with a healthcare professional before embarking on any fasting regimen. Especially if you have existing eye conditions.

Extended Fasting

Approach extended fasting (abstaining from food for longer periods) with caution. While some individuals report better clarity of vision during these fasts, others report the opposite. Thus, it is crucial to consider individual health, hydration, and nutrient intake during extensive periods without food.

Individual Variability

People need to acknowledge the effects of fasting on eyesight can vary widely among individuals. Genetics, existing eye conditions, overall health, and the specific fasting regimen all play a role in determining the impact of fasting on eye health.

Always consult a medical doctor when considering fasting as a potential tool for eye health.

Ophthalmological Monitoring During Fasting

Regular ophthalmological examinations and symptom recognition are essential components to ensure fasting remains a safe and beneficial practice for you.

Regular Eye Examinations

The foundation of maintaining good eye health during fasting is through regular eye exams. Keep up with your eye check-ups, especially if you are considering fasting or already practicing it. These examinations serve several essential purposes:

  • Detecting pre-existing conditions

  • Monitoring vision changes

  • Preventing complications

Symptom Recognition

In addition to eye exams, pay attention to any changes or symptoms during fasting.

Common eye symptoms to be aware of include:

  • Dry eyes

  • Blurry vision

  • Eye strain

Fasting often reduces fluid intake, potentially causing dry eyes. Symptoms are itching, burning, redness, and a feeling of grittiness. Using lubricating artificial tears and drinking plenty of water may help.

Some individuals report occasional episodes of blurry vision during fasting. We associate it with changes in blood sugar levels. If this symptom persists or worsens, you may need to stop fasting and talk to your physician.

Long periods of fasting, especially if spent in front of screens or reading, contribute to eye strain. It may cause eye fatigue, headaches, and difficulty focusing. To mitigate eye strain, take regular breaks and ensure proper lighting while working or reading.

Understanding the dynamic interplay between fasting and eyesight can empower healthcare providers and individuals to make better decisions regarding fasting regimens while preserving ocular health.

Stay informed about eye health topics in our Ophthalmology24 blog.


Checked by Atanas Bogoev, MD.


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