Any close-fitting glasses and goggles are prone to misting up in certain circumstances.
However, lens fogging is very much an individual thing - some people won't experience it at all while for others it can be a problem.
It seems to depend on factors such as the way a particular style of glasses sits on an individual face shape, the prevailing humidity in the atmosphere surrounding the wearer, and the circumstances in which the glasses are used.
7eye AirShield and Ziena Eyewear glasses are designed to help retain corneal moisture and provide a natural way to maintain a healthy and humid atmosphere around your eyes. For this reason they are commonly referred to as moisture chamber eyewear.
The downside of the moisture retaining function is that the risk of lens misting is also increased. In our trials of different brands of moisture chamber glasses over the past 10 years we have found that the 7eye Airshield and Ziena Eyewear glasses generally perform better than other brands as regards fogging.
This seems to be due to design features such as the filtered air vents that allow a small amount of air movement to pass across the lenses, which also have 7eye's and Ziena's own hydrophobic antifog coating on them to reduce the build up of condensation.
These features are normally sufficient to keep lens fogging within acceptable limits, but by following the tips in this article, you can further reduce the likelihood of condensation forming on your lenses.
Choosing which type of protective glasses to buy
Before buying glasses or goggles which you plan to wear with a protective eye cup or gasket, consider which type are most suited to the activities you will be doing when wearing them.
Activities which involve a significant amount of air movement such as cycling or motorcycling may be less prone to lens fogging than if you are stationary or moving slowly, particularly if the latter is associated with strenuous exercise.
In the former case, a close fitting frame with maximum insulated gasket would be a suitable choice, whereas in the latter case, sufficient protection may be achieved by wearing the 7eye glasses with the gasket removed.
We find that this still provides moisture retaining benefit and you can always put the gasket back in when using the glasses outside in cold, windy conditions.
Minimising fogging when using your glasses
If one or both lenses are fogging it generally means that the fit of the glasses is too tight on your face. The key is not to wear the glasses too tightly. A trickle of air movement is necessary to avoid fogging, and it will not significantly reduce the effectiveness of wearing moisture chamber glasses.
When your glasses are in use, you can minimise lens fogging with the following tips:
Ensure that the lenses are clean
Condensation forms more easily around dust particles so to minimise fogging you need to keep the lenses clean.
Remove the AirShield eye cup when cleaning the lenses
Gently wipe each lens when dry to remove dust, dirt, and smears before putting on the glasses because otherwise condensation forms more easily around the dust particles
Always use the 7eye red microfibre cleaning bag provided to wipe your lenses, (making sure that the microfibre surface is clean and dry before wiping each lens gently).
Never put the glasses away in their case while the lenses, frame, or eye cup are damp (for example if you got hot wearing them or if you wore them when it was raining or snowing.
When you have finished using the glasses, pat them dry with a clean, dry cloth, and sit them in the zip case without closing the case, until you are sure that the glasses are dry. Don’t put the glasses near a heat source such as a radiator or sunny window ledge, as this may damage the eye cup.
Don't put eye drops in just before wearing the glasses
Eye drops cause a surge in humidity around your eyes.
When you blink the excess moisture in the eye drops may be spattered on the lenses and can be difficult to clean off and act as condensation forming particles.
We recommend that you don't apply eye drops within half an hour of wearing the glasses.
Don't wear the glasses too tightly
A small amount of air movement is necessary to avoid fogging, and it will not significantly reduce the effectiveness of wearing moisture chamber glasses. We suggest you try the following tips to keep lens misting to a manageable level.
If the lenses start to fog up, push the glasses a short way down your nose, away from contact with your face. Slide them back to the normal position when the lenses have cleared.
If you are wearing the eyewear retainer to achieve a tighter fit, try loosening the toggle, or using the glasses without the retainer.
If you are wearing close fitting winter clothing around your neck or a woolly hat, try loosening it slightly to allow a little more air movement.
If you are wearing the 7eye Cape, try lengthening the arm by one click stop, so that you are not wearing the glasses so tightly
If you are wearing the 7eye Ventus or Panhead, adjust the ends of the ear rests so that you are not wearing the glasses so tightly. This will require you to change the angle of the hooked end of the ear rest.
Allow the glasses to adjust to changes in atmospheric conditions
Fogging up can just be a temporary problem that happens when the glasses are moved between locations that are very different in temperature or humidity, so give the glasses time to adjust to these changes.
For example, when you first get your 7eye glasses out of the case, wait a few minutes before putting them on. The same applies when going from outdoors to indoors when it is cold outside.
If your lenses continue to mist up
If you have taken the above steps to minimise the occurrence of lens misting, but you still get the same problem, try using an anti-fog spray. These are simple to use and widely available online and in specialist outdoor shops and ski shops. A popular brand, which has received positive reviews, is QuickSpit.
Apply the spray before using the glasses, following the manufacturer’s instructions carefully.