October 2015

Swimming With Contact Lenses – Is It Safe?

It’s warm and humid outside and nothing feels better than going for a swim to escape the heat. But you have poor eyesight and it irks you that you cannot wear your spectacles into the water. Aha! You’ve decided to put on your contact lenses to go for your swim. Just a little while won’t hurt, you say to yourself. But is that true? Let us explore this subject together.

The Risks

Assuming you are going for a swim and you put on a fresh pair of contact lenses, just for the occasion. You dive into the pool and the contact lenses get washed out of your eyes, never to be seen again. Yes, the risk of losing your contact lenses is real and it is something you can consider before you put them on the next time you go swimming.

It is a little known fact that fresh water can result in the soft lenses tightening on your eyes. Needless to say, having a piece of plastic squeezing your eyeball is not a comfortable experience.

Contact lenses serve as a medium that can retain chemicals and microorganisms, such as Acanthamoeba, which are usually washed away from your eyes if you are not wearing contact lenses. Prolonged exposure to these chemicals and microorganisms can potentially result in eye irritation, infection and even permanent impairment of your eyesight.

Preventive Measures

The safest measure to take is to avoid wearing contact lenses for your swims. Instead, purchase a pair of optical goggles which serve a dual purpose of being a pair of spectacles, as well as, goggles.

A slightly more risky approach would be to wear a pair of goggles when you are wearing contact lenses for your swim. However, there is a risk that some water might leak into your goggles and contaminate your contact lenses.  Hence, be sure to check that your goggles are of the right fit.

If you do experience any discomfort in your eyes, be sure to visit your eye doctor for a proper diagnosis. Sharing is caring, so do share this information with your bespectacled friends 🙂


sun protective clothing

Sun Protective Clothing

This is the last part of our 3-part series on sun protection.

After a long day at the beach with inadequate sun protection, you will find very obvious tan lines on your arms and legs. This is due to the fact that your clothing is able to provide you with some UV protection. However, is that enough?

Ultraviolet Protection Factor (UPF)

Instead of SPF (Sun Protection Factor), you will find that sun protective clothing will carry UPF ratings. A clothing’s UPF rating gives an indication of its ability to block both UVA and UVB rays.

UPF 1524 blocks 93.3%95.9% UV rays
UPF 2539 blocks 96.0%97.4% UV rays
UPF 4050+ blocks 97.5%98+% UV rays

Normal Clothing vs. Sun Protective Clothing

Back to the question of whether your normal clothing is offering enough UV protection, the answer is NO.

The UPF rating of normal clothing is estimated to be about UPF 6, which still allows about 17% of the UV rays through. Even a bottle of SPF 15 sunblock offers more protection than that! Therefore, if you are going to be staying under the sun for prolonged periods (e.g. kayaking), do put on clothing with higher UPF ratings. It is easy to find clothing with UPF rating of 50/50+. Billabong, Quiksilver and Uniqlo (women’s only) are some brands that carry sun protective clothing.

Is Sunblock Redundant Then?

NO! Definitely not!

Firstly, your sun protective clothing cannot possibly cover every inch of your body. Secondly, the UV protection of the sun protective clothing may be reduced when it gets wet, over-stretched, or worn out.

As such, in order to keep your skin protected from UV rays and to remain fair, you should still apply sunblock, even under your sun protective clothing. If you have a friend who refuses to put on sunblock just because he is wearing a rash guard, don’t forget to share this post with him 😉

sunglasses sun protection

Sunglasses – What You Must Know

This post is the second of SwimInSG’s 3-part series on sun protection.

Do you know that UV rays can cause cataracts, cancer of the eye, and even blindness? If you do not want to increase your risk of getting the abovementioned medical problems, you should definitely read on!

Sunglasses – How They Work

When you are under the sun on a bright and sunny day, the iris in your eye will constrict to reduce the amount of light reaching your cornea. When you put on a pair of sunglasses, the iris will dilate (open up) to allow more light to enter. The darker the tint of your lenses, the more your iris will dilate to allow light in (up to a comfortable level).

A label that you will commonly see when purchasing sunglasses is “UV 400”. This means that the lenses on the sunglasses can protect your eyes from both UVA and UVB rays.

Cheap vs. Imitation

There is nothing wrong with wearing a pair of cheap sunglasses. Brands such as Oakley and Ray-Ban are expensive as they spend a lot on marketing and branding, and these costs are being passed on to consumers. A pair of cheap sunglasses from a lesser-known brand may offer as much protection as a pair of Ray-Ban.

However, the problem lies with wearing a pair of imitation sunglasses. While they may be cheap and look as good as the real thing, it is actually very bad for your eyes. Most of the time, imitations will have the same “UV 400” label, but it actually does not provide UV protection. What you are paying for would probably be just for lenses that are tinted, and nothing more.

When you put on that pair of imitation sunglasses, it still protects your eyes from intense sunlight, and causes your iris to dilate. What this means is that by putting on that pair of imitation sunglasses, you are subjecting your eyes to greater risk than when you do not put on any sunglasses at all!

But I Wear Contact Lenses With UV Protection!

There are contact lenses that offer UV protection for the eye. However, as the manufacturer clearly states:

contact lens uv protection
Retrieved from http://www.acuvue.com/technologies-home on 3 Oct. 15

Now that you know about the risk of wearing sunglasses without UV protection, be sure to only buy sunglasses from reputable sellers, and throw out any pair of sunglasses without UV protection you may have. Don’t forget to share this piece of information with your loved ones as well 🙂

shallow water blackout

Sudden Death: Shallow Water Blackout

Shallow Water Blackout (SWB) can occur without warning and even the best swimmers are not spared should it be allowed to strike. Unlike what the name suggests, SWB does not only occur in shallow waters. In fact, it can happen in any body of water and it is difficult for the lifeguards to detect a victim of SWB due to its swift and sudden nature. The only way to prevent SWB from happening is to increase awareness of this little known killer.

SWB explained
SWB is due to hypoxia, which means low oxygen (O2) levels, to the brain. When one is breathing normally, the need to breathe is triggered by an increase in carbon dioxide (CO2) levels. The point at which breathing is triggered is indicated by the dotted line in the figures below. As seen in Figure 1 below, after breathing is triggered, the breathing action that takes place increases the O2 levels and lowers the CO2 levels.

shallow water blackout - hyperventilation

Figure 1: O2 and CO2 levels during normal breathing (Source: Wikimedia Commons)

In contrast, when a swimmer hyperventilates, his/her CO2 levels are at a reduced level. As seen in Figure 2, the O2 levels will enter the blackout zone before the need to breathe is triggered. After the swimmer blacks out and the CO2 levels continue to rise, his/her body will naturally take in a breath. The unconscious swimmer will then take in a lungful of water and drown.

shallow water blackout - normal breathing

Figure 2: O2 and CO2 levels when hyperventilating (Source: Wikimedia Commons)

Prevention of SWB

Firstly, SWB can be prevented by educating swimmers of the dangers of breath holding. While hypoxic training is practiced worldwide, swimmers should be discouraged from performing such training on their own. Recreational swimmers should also avoid engaging in breath holding for fun.

Next, in the event that breath holding exercises are necessary during training, they should be performed under close supervision of a swimming coach. The swimming coach should then take necessary precautions to ensure the safety of the swimmers under his/her guidance.

Lastly, lifeguards on duty do have the responsibility to perform patrols periodically. This is to ensure that all blind spots are covered in the event of a swimmer in trouble being submerged in such areas.

Hopefully, by raising awareness of this silent killer, unnecessary loss of lives can be prevented.