Recently, my friend's eyes were red, very dry and uncomfortable, and I went to the ophthalmology department to take a look, and I actually checked out the condition of hypoxia: corneal edema, corneal neovascularization, dry eye~
After looking for the reason, it turned out to be the fault of "contact lenses"!
The doctor said that it was good to come for an examination, and the new blood vessels are a manifestation of long-term severe hypoxia of the cornea. Once formed, it is irreversible.
Most of the patients encountered in hospitals are caused by long-term use of contact lenses / contact lenses with "very low oxygen permeability".
Contact lenses with low oxygen permeability can easily lead to corneal neovascularization, corneal edema, and epithelial abrasions [1-2], and long-term chronic damage to the limbal region, which is not easy to detect, and even gradually lose corneal epithelial stem cells, affecting its regeneration ability [3].
Swipe left to see
Therefore, contact lenses that need to be worn for a long time must first look at the oxygen permeability, otherwise it is easy to hurt the cornea~
Reduce eye damage from contact lenses
Oxygen permeability needs to exceed this value
Our cornea needs oxygen for normal metabolic activities. When oxygen supply is insufficient, the corneal aerobic metabolic balance is lost, resulting in corneal edema, epithelial damage, corneal neovascularization, and other effects [1].
For the sake of corneal health, oxygen conductivity (oxygen permeability: Dk/t value) is a very important indicator when choosing contact lenses!
The specific values are mentioned in "Contact Lens Science":
- Daily-wear lenses (day-thrown): Dk/t values greater than 24 are required to achieve corneal edema of 0 [4].
- Long-wear lenses (e.g., moon throwing): a Dk/t value of >87 is required to achieve corneal edema of less than 4%, and a Dk/t value of >125 to reduce edema to 3.2%[4].
If you want to find contact lenses with high oxygen permeability, the material is preferably silicone hydrogel. Because the oxygen permeability of silicone hydrogels is usually 5~6 times that of hydrogel lenses[5].
Oxygen dissolves in silicon to a high degree, just as a lens has many air holes for it to pass through. Compared with hydrogels, silicone hydrogels have an additional silicon channel, allowing oxygen to pass through more smoothly [5].
Don't choose too high a lens with a moisture content
Otherwise, it is easy to cause dry eyes
Many people have a misconception that the higher the water content of contact lenses, the more hydrated their eyes are. Quite the opposite, actually.
Lenses with high water content need to absorb water from tears in order to maintain water content, which can easily cause dry eyes when worn.
It is recommended to choose a water content between 40%~60% for a long time [6].
From the point of view of water content, silicone hydrogel material is also a better choice.
Because hydrogels rely on high water content to increase oxygen permeability, silicon hydrogels do not rely on water, it has separate silicon channels to increase oxygen permeability.
Silicone hydrogels can also maintain the relative physiological balance of tear film osmotic pressure and mucin, improving dry eye [7].
-Ad-
Knowing that you don't want to bother to choose, we helped you find this contact lens with ultra-high oxygen permeability from ophthalab in France (the color film is in the last two segments, daily and monthly are available).
透氧量高达 187.5 Dk/t
The water content is moderate, and it is not easy to cause dry eyes
Contains non-ionic NVP to reduce protein precipitation
Oxygen-dimensional silicon hydrogel daily & monthly polishing 👇
Shanghai Machinery Guangshen (Wen) No. 250730-51683
It's not that it's expensive and can't afford it, we are more cost-effective, not to mention that this contact lens is also available at a good price for a limited time:
Oshutian Oxygen Monthly Disposable 3 Tablets Single Box is 64 yuan, and the lens box and care solution are free when you buy it. Buy 2 boxes and get 20 yuan off, 54 yuan / box when you get it, plus wet wipes.
It is also recommended to buy 4 boxes of monthly throws to get 60 yuan off
Stack the money-saving card and get another 5 yuan, getting 47.7 yuan / box
Each pair is worn for a month, and the average is only 1 yuan per day!
If you don't want to take care of your contact lenses and are used to wearing them daily, the full oxygen daily disposable (30 pieces) + 5 pieces trial pack also has a great price:
Buy 4 boxes for 44 yuan off, and stack the money-saving card for another 15 yuan
Get 90.25 yuan / box, and include 20 pieces of trial packs!
In addition, the daily disposable buy and get a free wearer, 2 boxes plus 5 wet wipes, and 4 boxes plus eye lotion.
Tips
Silicone water material has a high degree of formability, high oxygen permeability, and is particularly suitable for the eyes because of its hydrophilic and lipophilic characteristics.
It is recommended to reserve 5 days for the first wear, and gradually increase the wearing time every day from the first day of wearing for 2~3 hours.
All purchasers are entitled to the Safe Purchase service, that is, a full refund for any discomfort - within 15 days of receiving the goods, if the trial wear (no more than 5 times) feels uncomfortable, and the formal wear is not opened, you can contact customer service to return the formal wear and apply for a full refund.
The conversion is shown on the product detail page
Shanghai Machinery Guangshen (Wen) No. 250730-51683
Shanghai Machinery Guangshen (Wen) No. 270813-57560
Cornea friendly
The Hexagonal Warrior is it
After all, it is something that touches the cornea, and we have to try it ourselves before recommending it to you.
Several of our colleagues wore the "all-oxygen dimension" monthly throw, and used it for more than ten days, and the most direct feeling was "unexpectedly comfortable".
I never expected it to be super breathable, and my eyes are not only not dry, but also very moisturized.
01
The oxygen permeability is super high, and the cornea supplies enough oxygen
Why is it so comfortable to wear?
First of all, it is because it uses a high-cost "silicone hydrogel" material. It contains hydrophilic silicon-containing polymeric materials and hydrophilic monomers with high oxygen permeability.
The oxygen permeability is not blown, and it is clearly marked on the packaging:
The oxygen permeability of the daily disposable is 171.4 dk/t, and the monthly disposable needs to take more care of the eyes, because knowing that you use it for a little longer, the monthly disposable oxygen permeability is as high as 187.5 dk/t.
Monthly (left) and daily (right) oxygen permeability
02
The water content is moderate, and the preservation solution is added with a double moisturizing factor
Lenses with high water content need to absorb water from tears in order to maintain water content, which can easily cause dry eyes when worn. For longer periods of time, it is advisable to choose lenses with a moderate moisture content [6].
A moisture content of 40%~60% is moderate, and a moisture content greater than 60% is a high moisture lens[6].
Especially for people with dry eyes, it is not advisable to choose lenses with too high water content.
This "Oxygen Contact Lens" has a moderate water content (47%), and the preservation solution also adds hyaluronic acid and sodium alginate to double moisturize.
Wearing it is less likely to cause dry eyes and makes eyes more moisturized.
03
Contains non-ionic NVP to reduce sediment
Most of the contact lens precipitates come from fragments of eye tissue, which are rich in nutrients such as proteins, lipids, minerals, etc., which are needed for the reproduction of pathogenic microorganisms such as bacteria and fungi.
The "Oxygen Dimension" series of contact lenses is made of non-ionic NVP, which can resist sediment, and protein precipitates and protein-based pathogenic microorganisms have less attachment.
04
The total diameter is 14 mm, and the base arc radius is 8.7 mm, which fully covers the cornea
Soft contact lenses must cover the cornea adequately, at least 0.5 mm beyond the edges.
The cornea is about 12.0 mm in diameter, and since the lens is not fully centered in the eye, the lens should be at least 13.6 mm in diameter.
With a diameter of 14 mm, the Oxygen lenses cover the cornea and are thin (center thickness: 0.08 mm) with a hint of light blue, making the eyes beautiful and bright.
The conversion is shown on the product detail page
Shanghai Machinery Guangshen (Wen) No. 250730-51683
Shanghai Machinery Guangshen (Wen) No. 270813-57560
Protects against ultraviolet rays
Long wearing time and great value
In the hot summer, our cornea needs to resist ultraviolet rays! And this lens happens to be added with a UV absorber, which belongs to the category 2 of UV absorption.
Knowing that you often look at your phone and type on the keyboard,