What is the difference between hard and soft contact lenses?
The concept of the contact lens was first conceived by none other than Leonardo da Vinci in the year 1508. For centuries, the idea of the contact lens stimulated the scientific and medical imagination, but it would take until the early 1970s for suitable modern materials to be developed to make those complex lenses that were effectively suitable for human use.
Today, contact lenses are becoming increasingly comfortable, more durable and can also be worn for longer than ever before. If you are still unsure whether contact lenses are the right choice for you, you can compare hard and soft lenses.
Hard contact lenses
Hard contact lenses are generally known as so-called 'semi-rigid gas' permeable lenses or RGPs. They are now made of plastic-like material, although they were originally manufactured in glass. For many years that hard lenses have been made, this was done from a material called polymethyl methacrylate (PMMA).
These contact lenses tended to be uncomfortable to wear because they did not allow oxygen to pass through.
Even though they were designed to move slightly each time the eye closed and reopened, in order to allow good oxygenation of tears, this meant that the wearer of the lenses had to open and close their eyes more to allow the eyes to be sufficiently moistened and ventilated.
Even though they are so-called hard lenses, they still have the necessary flexibility, somewhat comparable to the usable part of a plastic spoon. The disadvantage is that wearers of these lenses are constantly aware that they have the lenses in, although this feeling may decrease over time.
This type of lens is custom-made to the shape of your cornea. Because they are made of a rigid material, this type of lens will retain its shape better than the soft lenses and will therefore provide long-lasting and clear vision. You can therefore wear them for longer than soft lenses, which will lead to more tear production more quickly.
Hard lenses are made from certain materials that do not contain water, which means that a single pair can last for years, provided you maintain and store it correctly.
In addition, this type of lens can also be custom-made based on the wishes and needs of the wearer, making it possible to correct a wider range of visual problems than is the case with soft lenses.
The advantage of hard lenses is that wearing them leads to high-quality vision and that they can also correct the progression of nearsightedness to some extent.
Unfortunately, there are also disadvantages.
For example, this lens is still not as comfortable to wear as soft lenses, and they also tend to fall out of the eye more often.
It is also the case that a person who wears this type of lens, when he decides to put on his doctor-prescribed glasses again for a few days, will find that his eyes are no longer adapted to this type of lens.
To ensure optimal and consistent comfort, the wearer of RGP lenses will have to wear them on a daily basis, which is of course not ideal for everyone.
Soft contact lenses
People often specifically and emphatically choose soft lenses because they are ultra-comfortable to wear. In fact, most people don't even notice they are wearing soft contact lenses.
They are made of plastic-like material, but their flexibility is more like that of household film used for food. Thanks to the latest modern technology, soft lenses are now available for almost any type of correction you can think of.
They are now also available in many colors. The best of the soft lenses are available in a disposable version, which means that they do not require special maintenance such as the use of certain chemical cleaning products. You simply wear this type of lens for a day and then throw it away.
Soft contact lenses are so called because they absorb water. The water content of a soft lens at full saturation can vary from 37% to about 80%.
Soft lenses that contain a high concentration of water can remain comfortably in the eye for a longer period of time and are generally described by the marketing guys as lenses for long-term wear.
For many years, soft lenses were considered a remarkable innovation in lens technology. They were smaller and thinner than their predecessors of yesteryear – the hard lenses – and they provided clear vision for thousands and thousands of people who did not find it comfortable to wear hard lenses.
Currently, soft lenses are still the most common variety of contact lenses, but with the advent of the new and promising RGP lenses, it seems as if that superiority will be increasingly shaken in the near future.
However, soft lenses still retain a number of clear and certain advantages when we compare them with the new generation of hard lenses.
Soft lenses are immediately more comfortable to wear than the previously mentioned RGP lenses. This latter type of lens always requires a longer period of time before the eyes have become accustomed to it.
For these reasons, soft lenses will still be a more flexible solution to wear. Someone who wants to wear both contact lenses and glasses can easily switch between the two solutions without sacrificing wearing comfort.
On the other hand, it must be said that soft lenses easily absorb remnants of soap and lotion that may remain when washing your hands, which can lead to an annoying imitation of your eyes.
Proteins and lipids will accumulate over time even with non-replaceable soft lenses, which may lead to the need to replace the lenses more quickly.
Known general facts regarding soft and hard contact lenses
Both types of contact lenses, both hard and soft, are fairly easy to use and maintain. There are two things you should definitely avoid, namely wearing these lenses during sleep and having them in longer than indicated by the manufacturer and the specialist.
But if you follow the correct procedure and maintenance for these lenses, it is unlikely that you will have any problem with an infection.