FIGHTING THE FOG

Fogging of glasses has always been an irritating problem for some people in some situations but since the mandatory wearing of masks to protect ourselves and others from COVID-19 the problem has become more widespread. With a global pandemic to worry about right now the last thing we need is something as simple as foggy glasses to add to our concerns. But there are a number of solutions to lift the haze and brighten the day!

Glasses fog up because the mask directs the breath upwards instead of forwards, which is necessary for preventing disease transmission but annoying when it interferes with vision. The simple science behind it is that when warm air hits a cool surface condensation occurs. The lenses of the glasses are relatively cool compared to the breath, so that when the water vapour from the breath comes in contact with the cool surface of the lenses it changes into tiny droplets of liquid forming a film which we experience as fog. Glass lenses are more likely to fog, whereas lens materials like polycarbonate and plastic may be more resistant to fogging.

As the demand increases for anti-fog products, a number of optical companies are offering new products, special lenses and lens coatings to help alleviate the problem. One company has developed technology that permanently prevents build-up of vapour on the lenses, while another uses a physical process to produce a long-term and reliable coating layer rather than relying on chemicals that provide only a short-term effect. Anti-reflective treatments are a good option as they not only reduce glare, but often include a coating that resists water, smudging and fogging.

Products that may be applied to glasses include liquids, sprays and wipes. As well as cleaning and defogging, one particular anti-fog lens cleaner has anti-streak and anti-static properties. Ask your optometrist to recommend the most suitable product for your needs and the one which will not interfere with any special coatings on your lenses.

Various home remedies have been suggested to keep glasses fog-free. Some are more effective than others, but with all of them you need to consider whether damage may be done to the lenses of your glasses. Check with your optometrist. One idea is to wash the glasses with warm soapy water, shake off the excess liquid and allow the lenses to air dry or gently dry them with a soft cloth. The soap leaves behind a thin film which acts as a fog barrier. A word of caution is to ensure that the soap does not contain abrasives or other substances that may scratch the lenses, and likewise that the cloth used will not cause damage.

Some less advisable ideas include rubbing the lenses with a potato or toothpaste which should be avoided because it contains tiny particles that are great for cleaning your teeth but guaranteed to scratch your lenses. Household cleaners like vinegar, ammonia and surface sprays should be kept well away from your glasses. Never use hot water which can damage both the lenses and the frames.

There are steps that can be taken to make wearing the mask with glasses less uncomfortable. Make sure the mask fits securely over the nose. By pulling the mask up higher on your nose, you can use your glasses to create a seal which will keep the warm air from escaping through the top of the mask. Another suggestion is to fold a tissue horizontally and put it between your face and the top of your mask, so that it sits over the bridge of your nose; the moisture from your breath will be absorbed by the tissue instead of fogging your glasses. Use a mask with a nose bridge that can be bent and shaped to fit over the nose. This may seem obvious but keep your glasses clean. Dirt, smudges and scratches on the lenses make condensation worse. Avoid leaving fingerprints on the lenses and handle glasses carefully to prevent scratching.

Unless your lenses include an anti-fog treatment, fog prevention remedies are only temporary, and you need to reapply them regularly for the best results.