Frames glasses and contact lenses are the most common means of correcting refractive errors, but many people need clarification about their use and care in everyday life. Today we'll look at some of the most common questions with contact lenses.
Contact lenses are clear contact lenses used to correct vision in the cornea, which are more specialized; contacts are colored contact lenses with colored lenses which change the color of the iris through a particular concentration of color and have a fashionable cosmetic effect. There are soft and hard contact lenses, while contacts only have soft hydrophilic ones.
OK lenses and RGP are rigid corneal contact lenses made of rigid, highly oxygen-permeable contact lens materials. The difference lies in their scope of application and correction effect.
OK Lenses: The scope of application is somewhat limited by the design principle of OK lenses. Generally, OK lenses are suitable for adolescents with developing eyes to control nearsightedness development. The wearer is required to have no apparent eye disease and normal cornea; in addition, OK lenses are night-wear type, which can be worn at night to sleep and have good naked eye vision without wearing lenses during the day.
RGP: It is a day wear type, which means that it should be worn during the day, is suitable for most people of all ages, and can correct myopia up to 2,500 degrees and astigmatism up to 600 degrees; the particular design and high oxygen permeability of RGP make it suitable for most refractive error patients, and there is no age limit.
When you go home at night to take off your contact lenses and change the care solution, many people casually put them in the bathroom or by the sink; this is a vast hidden, dangerous behavior.
The environment in the bathroom is more humid, which is more conducive to bacterial reproduction and susceptible to bacterial infestation. Contact lenses and their care products should not be stored in moist environments such as bathrooms and refrigerators, whether opened or unopened. They should be stored at room temperature below 25 degrees and out of direct sunlight.
With the variety of shopping options available today, many people will purchase contact lenses online. But more than just knowing the prescription and choosing a wear cycle is required; to buy the right contact lenses, you also need to see the water content, diameter, base arc, and other information.
The water content of a contact lens is the percentage of water contained in the lens itself. Contact lenses deliver oxygen to the eye through the water in the lens, and the amount of water needed by the lens is fixed, so when the lens loses water while wearing it, it absorbs tears to replenish the water required by the lens. So sometimes, the dryness and discomfort that occurs during contact lens wear are due to improper choice of water content.
As you can see, the higher the water content of contact lenses, the more tears they absorb and the drier your eyes will feel. Do not buy lenses with high water content if your eyes are dry. However, if the water content is too low, it may cause the lenses to have poor oxygen permeability. Therefore, a water content of about 40% to 60% would be more appropriate.
The lens diameter is chosen based on the diameter of the cornea, which is around 12.0mm in our case, to ensure that the contact lens covers the cornea and provides the right amount of movement. Contact lenses are generally chosen for lenses that are usually more than 1.5mm larger than the diameter of the cornea, with the most common contact lens diameters ranging from 13.5mm-14.5mm.
The base arc is the radius of curvature of the cornea, which is a measure of the degree of curvature of a contact lens and is related to the fit of the contact lens. The larger the base arc, the flatter the inner surface of the lens, and the looser the lens will fit in the eye. The smaller the base curve, the steeper the inner surface of the lens and the tighter the lens will be in the eye.
If the base arc is chosen too large, the lens will not fit the eye, and the lens will be easily displaced. The eye will feel foreign bodies, and the vision will be unstable. If you choose too small, your eyes will feel too tight and uncomfortable, your eyes will be red and sore for a long time, and your cornea will be more prone to edema. And it will cause the lenses to fall off easily, resulting in blurred vision, dry eyes, and other symptoms.
The white spots on contact lenses that cannot be rubbed off are protein deposits, which significantly impact the eyes. The proteins adsorb to the lens and, over time, form a thick wall that can easily scratch the cornea. Left untreated for a long time, it is likely to cause various eye complications and other eye diseases.
Contact lenses are attached to the cornea and cannot come into contact with air. No matter how high the oxygen permeability of the lenses is, prolonged wear will decrease resistance due to a lack of oxygen and normal metabolism. In addition, contact lenses are a foreign substance in the eye. When closed, they can cause friction to the cornea and eyelid conjunctiva, which can lead to bacterial infections and keratitis, and conjunctivitis. Wearing contact lenses to bed can increase the chances of eye infection by 6 to 8 times.
So you can't wear contact lenses while sleeping to avoid irreversible damage to your eyes, but pay attention to eye hygiene and contact lens care; the rest of the time, there is no problem wearing them.