Silicone hydrogel contact lenses

Silicone hydrogel contact lenses are recommended by most ophthalmologists. They combine the advantage of two materials: silicone and hydrogel. They began to produce them not so long ago, this is the latest invention in the field of ophthalmology and vision correction. The new combined material is so superior in its properties to hydrogel that it was originally intended for continuous wear – prolonged mode, including night mode, to wear lenses without removing them for up to a month, 30 days .

However, over time, their use expanded and silicone hydrogel lenses began to be prescribed for the usual, daily regimen. Today they are extremely popular for high comfort and safety.

Benefits of silicone hydrogel contact lenses

• Excellently hydrated, they don't dry out by the end of the day, so they provide long-lasting comfort without redness or dryness. Sufficient moisture content is provided by the hydrogel material in the composition, as well as natural moisturizing ingredients.
• They pass 5 times more oxygen than hydrogels. This property eliminates oxygen starvation of the cornea.
• Despite the fact that they are stiffer and denser, they are preferred by many because they hold their shape better and are easier to put on and take off.
• Many silicone hydrogel lenses are approved for extended wear, even up to 30 days without removal, due to for the high transmission of oxygen in such lenses you can sleep.

Features of silicone hydrogel lenses

Due to the greater rigidity and density, due to the content of silicone in the composition, it takes a little longer to get used to them at the first use. In addition, when switching to silicone hydrogel lenses from hydrogels, it is better to consult an ophthalmologist to determine the radius of curvature, since their fit may differ.

Silicone by itself would not be able to provide sufficient moisture to the lens due to its hydrophobicity. Therefore, the lenses are plasma treated so that their surface can be wetted by the tear film during wear. However, some users have to resort to special moisturizing eye drops to prolong the comfort of wearing lenses.

Contraindications include allergy to silicone.

Wearing modes and replacement periods

Silicone hydrogel lenses come in a variety of wear modes: daily, flexible, and extended wear. They are also one-day, two-week, monthly, three months.

Since they are allowed for extended wear, they are suitable for those who sometimes sleep in lenses and who have to spend a long time in them, it is not always possible to remove them in time and put them in a container. As we know, there are even contact lenses that can be safely worn for 30 days without removing, and in this mode the eyes will receive enough oxygen.

Types of silicone hydrogel

There are many types and generations of this material, which can have various technical names and modifications: balafilkon, halifilkon, kalifikon, komfilkon, lotrafilkon, narafilkon, senofilkon, enfilkon. In 2016, Alcon introduced the 4th generation of silicone hydrogel lenses with a record high moisture content of 100% and oxygen permeability Dk/t = 156.