What You Need To Know About Light And Your Eyes
Jul 30, 2018
Introduction
We need light to see things. The light could be directly from a light source (eg a light bulb) or get reflected off from the object. These lights enter our eyes, which convert into signals that send to the brain for interpretation. We will then know what we see: a table, a chair, light from the sun etc.
Range of Light Rays
The light is emitted in wave patterns of different wavelengths. Based on the wavelengths, the light is divided into visible and invisible light. The visible light range contain shades of rainbow colours, start with red light (longer wavelength) and end with blue light (shorter wavelength). The light rays with wavelength shorter than the blue light is categorised as invisible light range, which consist of ultraviolet (UV) light.
Light enable us to see what’s around us. But, are you aware that overexposure to certain light rays can damage our eyes? Which light will that be? And what will it do to our eyes
Blue Light
It has the shortest wavelength among the visible light range. Aside from sunlight, it also come from man-made light sources, such as fluorescent and LED lighting, and digital screens of electronic devices (eg smartphone, television, computer etc). All blue light can pass through our eyes and get fully absorbed at the inner part. The percentage of blue light transmission is age related, whereby children’s eyes will transmit more blue light than adults and elderly.
The blue light is important to regulate circadian rhythm – the body’s natural wakefulness and sleep cycle. Normal exposure assures healthy circadian system and better sleep quality. On the other hand, over exposure not only negatively affect our circadian clock (that’s why we always encourage no screen time before sleep), but also harmful to our eyes, especially the light-sensitive parts in the eyes i.e. the macula and retina. This causes our eyes to get tired more easily (known as digital eye strain). Overtime, continuous damage increases risk of macular degeneration (the central vision becomes blur) or glaucoma (progressive loss of side vision) and may eventually lead to blindness if left untreated.
Ultraviolet (UV) Light
When we see bright light (the visible light), our eyes squint automatically as a natural defence reaction. However, there’s no such response when the UV light is strong. Hence, this light is called the invisible light. Same as visible light range, UV light come from the sunlight and man-made UV irradiated lighting. Moderate UV light exposure is essential for natural vitamin D production in the body; nevertheless, too much exposure is harmful for skin and eyes.
Besides skin protection, it is also important to protect our eyes from UV light damage. We usually unaware of getting strong UV light exposure especially on a cloudy day, or strong light reflection from the water etc. Most UV light unable to reach the inner part of eyes due to being absorbed by the cornea and lens. Hence, the associated eye diseases – cataract for example, are commonly found at areas exposed to intense UV light.
What to do?
Of course, there are some preventive actions for eye protection. Considering the trend of using natural alternatives in health aspect, you can protect your eyes from these harmful lights by including eye-nutrients such as lutein, zeaxanthin and other sources of natural antioxidant in your diet. You can get them by taking a variety of colourful fruits and vegetables. Nevertheless, people nowadays are so busy and prefer a quick-to-go solution. Therefore, you can opt for eye supplement which contain all these natural ingredients in one tablet/capsule (eg: BiO-LiFE Bio-Vizion). Now, you can protect your eyes easily with just a convenient one-a-day dose.
References
- Heiting G. 2017. Blue Light: It’s both bad and good for you. Retrieved on 4 July 2018 from: https://www.allaboutvision.com/cvs/blue-light.htm
- Prevent Blindness.org. How can UV rays Damage Your Eyes. Retrieved on 4 July 2018 from: https://www.preventblindness.org/how-can-uv-rays-damage-your-eyes
- Tosini G, Ferguson I & Tsubota K. 2016. Effects of blue light on the circadian system and eye physiology. Molecular Vision. 22: 61-72.
- World Health Organisation (WHO). Ultraviolet radiation (UV) – The know health effects of UV. Retrieved on 05 July 2018 from: http://www.who.int/uv/faq/uvhealtfac/en/index3.html
- Yam CS, J & Kwok KH, A. 2013. Ultraviolet light and ocular diseases. International Ophthalmology. 34(2): 383-400.
