If mobile phones are the 'new organ' of the modern age, what are contact lenses for those who don't want to wear rimmed glasses and undergo myopia surgery?
Even though we've heard the pitfalls of "injured corneas" and "susceptibility to infection" over and over again, here comes the double 11 stockpile of contact lenses, aren't you soft? And - slow! If you wear contact lenses regularly, the consequences of choosing the wrong lenses could be worse than not having the right care routine in place!
Dr. Tsuen Luo, a specialist in optometry and corneal and ocular surface diseases at Quality HealthCare, talks to you today about how to buy and wear lenses wisely.
Whether contact lenses are right for you depends on this index
One thing that most contact lens wearers overlook is that it is called Florida
Technically speaking, contact lenses are fitted at a hospital.
To get fitted for glasses or do we have to go to a hospital for improvement? This is the type of research article that everyone should have seen for themselves, and it's actually the same with contact lenses. Both options for correcting myopia in students are based on the principle that a pair of concave lenses can be used to shift the focus back in front of the retina. Only the 'invisible' concave lens is worn directly on the cornea.
The reason why we are not advised to buy contact lenses from opticians or e-commerce shops without being tested by an ophthalmologist is that each person's ophthalmological data is highly individual.
Below are the contact lens instructions, which list the various parameters. Contact lenses are not suitable for use depending on whether the "base radius" matches the radius of curvature of the individual cornea.
The ophthalmologist firstly chooses a suitable radius of curvature based on the eye parameters of the wearer. Secondly, we have to assess the trial fit, as the actual working conditions after wearing the lenses vary from one individual to another, and the face-to-face assessment method is the only way to determine whether the lenses are suitable.
In addition, friends often ask: what is the diameter of the cornea and the width of the eyelid fissure (the distance between the upper and lower eyelids when the eye is open) that should be taken into account when buying contact lenses? In fact, these two sets of data have little or no influence on the choice of contact lenses. This is because the diameter of the contact lens itself will be larger than our cornea. Unless the eye is very small, it is difficult to wear a lens with a diameter that is too large.
The comfort of contact lenses depends on this indicator
The key to contact lens comfort is not the price, but the "oxygen permeability", which refers to the amount of oxygen that can reach our eyes through a contact lens product.
High oxygen permeability lenses ensure that our cornea absorbs a large amount of oxygen.
In some cases, instead of the Chinese word "oxygen permeation", the manuals use the term "DK/t", whose value is often followed by a long list of units (cm/s) (mLO2/(mL.hPa), "we don't care, just remember the number.
The contact lens pictured below has an oxygen permeability of 19.6.
Conventional hydrogel materials: Oxygen permeability up to 10 ~ 30.
New silicone hydrogel materials:Oxygen permeability of 60 ~ 80 or more.
Underline! If you need.
High frequency contact lens wear.
Wearing glasses continuously for more than 8 hours.
Need to wear lenses for naps.
There is no need as a business to purchase new silicone hydrogel glasses with high oxygen permeability, otherwise we run the risk of "corneal hypoxia". Oxygen deprivation can affect the cornea and lead to complications such as corneal infections, neovascularisation and oedema through the cornea. Can you really take a lesion that happens in your own eye lightly?
Of course, contact lenses with high oxygen permeability are also expensive. If it's out of your budget, change your thinking - increase the frequency of wearing frames and reduce the amount of time you spend in contact lenses at a time.