December 2023

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With summer comes fun outdoors and cooling off with a swim, but also exposure to the harmful rays of the sun and the risks present in water. While tanning beds and activities such as welding produce UV light, the biggest UV threat to the eyes is the sun. Our eyes are also vulnerable to the invisible dangers in the ocean, lakes, rivers and even chlorinated swimming pools.


There are three types of ultraviolet radiation from the sun, UVA, UVB and UVC. The appropriate amount of ultraviolet radiation benefits the body by facilitating the processing of vitamin D in the body, producing serotonin and aiding bone development. Overexposure to ultraviolet rays can be harmful to the body and particularly the eyes. UVC radiation is considered a minimal threat because it is absorbed by the earth’s ozone layer. Exposure to UVA and UVB rays poses a risk for both short-term and long-term damage to the eyes and vision.

Short-term exposure to ultraviolet radiation can cause damage in the eyes that is similar to a sunburn. The eyes become red and puffy, feel gritty, are sensitive to light and there is excessive tearing. Fortunately, these symptoms are usually temporary. However, damage from UV radiation is cumulative over a person’s lifetime and if the eyes are exposed to long-term UV radiation without adequate protection, there may be a greater risk of developing cataracts and/or macular degeneration later in life.


With so many options available, it is difficult to know which sunglasses offer the best protection. Most reputable brands of sunglasses list the amount of UV protection on the label, which should say “100% protection against UVA and UVB” or “100% UV400 protection”. No label generally means no protection!

It is understandable to think that the darker the lenses are, the more effective the protection, but this may not necessarily be true. They may block visible light but do not automatically block UV radiation. Unless it is specifically indicated, dark lenses may not offer better protection. While filtering out ambient light and glare, very dark lenses may cause the pupils to open to allow more light to enter the eyes, increasing rather than reducing UV light exposure. The lenses should be dark enough to keep the eyes comfortable, but not so dark that they reduce vision.

Various tints in varying degrees of darkness are available for different activities. Your optometrist will guide you towards the one most suitable for your lifestyle.

UV protection is sometimes included with polarised lenses. Polarised lenses are designed to reduce glare off reflective surfaces and to improve clarity and contrast, but polarisation alone does not protect the eyes from UV radiation. Make sure that UV protection is specifically stated on the label.

Large lenses provide more coverage to the eyes and the delicate skin around them, and wraparound sunglasses offer even better protection from both direct and peripheral sunlight. Whatever style you choose, make sure that they fit comfortably and offer the best possible UV protection.


Bodies of water, from lakes and rivers to sparkling swimming pools, are contaminated to a greater or lesser extent with bacteria and organisms that can affect the eyes. Whether simply cooling off, diving underwater or being sprayed with water while waterskiing, the eyes are at risk. Bacteria in water can cause an infection of the cornea, which can be painful and become serious if not treated. The chemicals in swimming pools can irritate the protective tear film of the eyes, leading to redness and light sensitivity, but the discomfort is typically temporary.

As a general precaution against contamination and irritation of the eyes, wear water-tight goggles that prevent water from getting into the eyes. After getting out of the water gently wipe water from the eyes with a clean towel. Use lubricating eye drops to moisturise the eyes, and drink water to retain hydration which is of benefit to the entire system as well as the eyes.

It has been recommended that contact lenses are not exposed to any water, including tap water, swimming pools, lakes, oceans, showers and even saunas, no matter if it is fresh water or chlorinated. Contact lenses should be removed before engaging in any water activities to avoid the high risk of irritation or infection from bacteria or viruses that can lodge between the contact lens and the eye. Exposure of soft contact lenses to water can cause them to tighten against the eye. Added to that, soft contact lenses are porous, allowing chemicals and bacteria to enter the eyes.

If it is not possible to swim without contact lenses, wear well-fitting goggles while swimming, remove the contact lenses immediately afterwards and soak them in a contact lens solution. Allowing the lenses to be completely disinfected eliminates the risk of exposing your eyes to bacteria that could have been absorbed into the lenses.

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This newsletter article is authored by EyeMark.
The views and opinions expressed herein are not necessarily those of the optometrist.