The advantages and disadvantages of contact lenses:
1) Advantages of contact lenses:
(1) Elimination of the role of prism: the higher the lens power, the greater the role of prism. As contact lenses move with the eye, the center of contact lenses in both eyes is shifted less, which can avoid the interference effect of trigonometry.
(2) Elimination of oblique astigmatism: when wearing ordinary glasses, because the eyeballs behind the lens rotation, sometimes applied to the peripheral part of the glasses, affecting refractive correction and produce oblique astigmatism. And contact lenses move with the eyeball, the center shift is less, basically no oblique astigmatism.
(3) Reducing binocular retinal aberration: For refractive error patients with large differences in refractive error, it is difficult to integrate due to the magnifying and reducing effects of lenses. The closer the lens is to the eye, the smaller the magnification rate is. Wearing contact lenses can basically restore the fusion function of both eyes and ensure monovision.
2) Disadvantages of contact lenses:
Some discomfort after wearing lenses; more troublesome to take and wear; uncooperative children, corneal hyperalgesia, outdoor workers, poor working environment should not be worn; related complications.
3, contact lenses classification, types
Currently commonly used contact lenses are hard contact lenses and new oxygen permeable hard lenses;
Wearing mode: long wearing type (day and night wear) and daily wear type (daytime wear only)
Classification:
1), according to the material of the contact lenses, it can be divided into hard contact lenses (PMMA polymethylmethacrylate) and pro-vision lenses (PMMA polymethylmethacrylate). methyl methacrylate) and hydrophilic soft contact lenses (HEMA-hydroxyethyl methacrylate) and the newly developed disposable long-wear soft lenses.
2) According to the wearable time of contact lenses, they can be categorized into long-wearing and disposable contact lenses (daily disposable, monthly disposable, quarterly disposable, semi-annual disposable, and year-round disposable, etc.).
3) According to the function of contact lenses, they can be categorized into therapeutic and cosmetic.
Types:
Nowadays, contact lenses are broadly categorized into rigid contact lenses (RGP) and soft contact lenses (SCL) with high oxygen permeability and gas permeability.
1), soft contact lenses (SCL)
Soft contact lenses can absorb water, permeable to oxygen, soft and curved, less irritation to the cornea, in line with the requirements of corneal respiratory metabolism, can be used for general myopia, hyperopia and astigmatism correction, is the mainstream of the current contact lens products.
Advantages: good plasticity, very comfortable to wear, short adaptation time. It can be worn intermittently as it does not require repeated adaptation. With a large diameter, the edge of the lens is located under the upper eyelid, avoiding the foreign body sensation caused by friction between the eyelid and the edge of the lens, and the lens will not fall out of the eye. The softness, absorbency, and large diameter of these lenses allow for their therapeutic use in ocular surface disorders. The edges of the lenses are attached to the corneoscleral rim and are not easily visible, making them aesthetically pleasing. It can be dyed or painted for eye beauty and orthopedics.
Disadvantages: Low material strength, easy to break. Lens plasticity, correction of corneal astigmatism effect is poor. Strong surface polarity, easy to adsorb sediments in the tear fluid, pathogenic microorganisms and components of the care solution, leading to ocular complications, so the cleaning and disinfection procedures require strict, and must take into account the compatibility of lenses and care products. The oxygen permeability of the vast majority of lenses is not good enough for overnight wear.
2), high oxygen permeable gas permeable hard contact lenses (RGP)
RGP and SCL are the same as wearing on the surface of the eye, from the overall refractive state of the eyes, in order to achieve the purpose of correcting refractive error.
Advantages: RGP has good molding, not easy to deform, high quality of optical correction, especially for patients with high myopia and high astigmatism, the correction effect is better. For corneal irregular astigmatism caused by various reasons (e.g. conical cornea, keratoconus, post-traumatic surgery, etc.), RGP is not only the only method that can effectively improve the correction of visual acuity, but also control the development of the disease and play a therapeutic role.
RGP facilitates cleaning, less protein and fat precipitation, easy care process, low incidence of inflammation, its high oxygen permeability, small lens diameter, does not interfere with the normal physiological metabolic activities of the eye, better compatibility with the eye, safer than SCL, and is suitable for refractive error patients who have been wearing contact lenses for a long time.
Disadvantages: Because RGP is made of special material that does not contain water, the texture is hard, and there will be a mild foreign body sensation during the first wear, and the adaptation period is longer than SCL; when engaging in strenuous sports, its stability is not as good as SCL, and it is not as comfortable as SCL; and it is necessary to make the lens into a variety of specifications of the inner surface of the curvature of the surface to adapt to the different eye wearers, which increases the difficulty of the fitting technology and increases the price of expensive contact lenses. The price is more expensive.
3) Keratoconus (Ortho-K CL, OK lenses)
It is a kind of specially designed RGP, which can rapidly reduce myopia and significantly improve the naked-eye visual acuity of moderate and low myopia through reasonable physical orthopedics of the cornea, so that the patients can take off their glasses during the day. Most importantly, it can effectively control the growth of myopia, with obvious and precise effects, especially for young myopic patients under 18 years of age with rapidly developing myopia, i.e. some special occupational needs.
It should be noted that keratoplasty lenses are medical supplies that require high fitting techniques and good supporting medical equipment, and must be fitted under the supervision and guidance of an ophthalmologist or optometrist. In addition, the changes in the cornea after wearing the lenses are reversible, to maintain good therapeutic effects need to wear the lenses for a long time to observe, and the process of wearing the lenses need to be regularly reviewed.
Contact lens lens care program
1) Soft contact lens wearers must be required to carry out strict care and maintenance of the lens every day, so as not to affect the health of the eyes and the life of the lens.
2) Wash your hands with running water and neutral detergent;
3) Rinse the front and back of the lenses with the care solution for 5 seconds each;
4) Immerse the lenses in a case containing 2/3 capacity of the care solution and tighten the lid; soak the lenses for at least 4 hours.
First time contact lens wearers
First time contact lens wearers will experience some discomfort in their eyes. Therefore, first time contact lens wearers should gradually extend the wearing time. 2-4 hours on the first day, and then 2 hours a day, up to 12 hours; wearers who have stopped wearing contact lenses for more than two weeks are also advised to carry out the wearing time of first-time wearers. Even for those who are used to wearing contact lenses, it is recommended that they wear lenses for about 8 hours a day, and switch to frames for 1 or 2 days a week, which is good for the long-term health of the eyes.
The recommended wearing time for first-time wearers is as follows:
Days 1 2 3 4 5 6
Wearing time (hours) 4 6 8 10 12 14
If you experience any discomfort while wearing contact lenses, you should remove the lenses immediately and check for damage to the lenses, foreign objects attached to the lenses, and whether the lenses are worn upside down or upside down on the right or left side, etc. If you experience any persistent discomfort or severe symptoms, you should immediately remove the lenses and check for damage, foreign objects attached to the lenses, and whether the lenses are worn upside down on the right or left side. If there is persistent discomfort or serious symptoms, remove the lenses immediately and go to an eye hospital or the original prescription office for examination; do not put cosmetics and hairspray and other chemicals in contact with the lenses. If there are volatile chemicals in the working environment, avoid wearing them in the working area; when putting on make-up, wear the lenses before putting on make-up, and remove the lenses when removing make-up; clean the lens case once a week and boil it to sterilize it. Replace the case every three months; do not use the used care solution to treat the lenses again.
If first-time contact lens wearers experience mild dryness, photophobia, blurred vision, foreign body sensation, or magnified or reduced vision, it is a normal physiological reaction as long as the condition is not serious and lasts for a short period of time. Generally, after a small adaptation period, the symptoms will disappear naturally, the specific adaptation period required is related to the quality of the lenses and the individual's ability to adapt, generally from a few hours to a few days. If the symptoms persist or even worsen after a week of wearing the lenses, you should remove the lenses immediately and go to a dispenser or ophthalmologist for a detailed examination to find out the cause.
First-time contact lens wearers should be careful not to use contact lenses as eye lotion. If you want to use eye drops, be sure to check with your doctor or pharmacist to see if they are suitable for use with contact lenses.
Contact lens fitting procedure
(1), inquiring about the basic condition and the general condition: including filling out the health care card, inquiring about the purpose of the lens fitting and whether there are any contraindications.
(2) Pre-fitting examination:
a) Eye examination:
General examination: eyelids, lid margins, eyelashes, inner and outer canthus, cornea, iris, pupil, lens.
Special examination: corneal fluorescein seven-color, tear film rupture time, tear discharge time, tear secretion measurement, measurement of corneal sensation, examination of conjunctival bacteria, intraocular pressure examination.
b) Optometry
c) Measurement of corneal curvature
(3), selecting the appropriate fitting, evaluation, checking the corrected visual acuity after wearing the lenses, the degree of comfort, and the fit of the lenses with the cornea and the eyelids (including the centering of the lenses, the corneal coverage, the degree of movement, and the degree of elasticity).
(4) Dispensing of lenses and training in lens removal and post-fitting care (including how to take care of the lenses, timetable for the first fitting, normal signs that may occur with the first fitting and timetable for review).
Eight precautions for wearing contact lenses
1. Before wearing contact lenses, you need to have a standardized vision examination and eye health checkup, so that your doctor can check whether you are suitable for wearing contact lenses and what kind of contact lenses you should wear.
2. Choose the right lens prescription and lens base angle based on your optometry and measured corneal curvature.
3. Contact lenses may be broken for some reasons, and when the eye wears a damaged lens, there will be a foreign body sensation or even pain and redness, especially if the sensation occurs in one eye, it is more important to consult a doctor as soon as possible.
4. The lens case is generally recommended to be sterilized once a week and replaced every three months.
5. Unless the lenses are night-wearable, the lenses should not be worn to bed.
6. Regular or early replacement of lenses, contact lenses cause eye complications mainly due to lens deposits, should be replaced as soon as possible to keep the lenses clean and reduce the damage of deposits on the eyes.
7. Pregnant people, it is best not to wear contact lenses, endocrine changes, wear easy to have adverse reactions.
8. Swimmers, it is best not to wear lenses, unless the swimming goggles are completely sealed or replaced with new contact lenses after swimming.
Precautions for wearing and maintaining contact lenses
1. Confirm that the lenses are left and right, positive and negative before wearing them;
2. If there is a sense of irritation, remove the lenses to check whether there is dust or lint, etc.
3. Do not open the two lids at the same time, so as to avoid the left and right lids from being adjusted to each other;
4. Make-up can be applied only after the lenses have been worn; the face can only be made-up free after the lenses are removed;
5. Only after removing the lenses can you remove makeup from your face;
5. The moisture on the end of the finger of the lens wearer should not be too much, otherwise the lenses will be easy to stick with the finger and difficult to wear into the eyes;
6. Sufficiently open the upper and lower lids so that the lenses will have enough space to enter the eyes.
7, if in the process of wearing lenses failed to enter the eye, do not rush to wear lenses again, but should be fully rinsed lenses before wearing.
8, must read the instructions before using the care solution.
9, wear or remove contact lenses before you must clean your hands;
10, nails can not be too long or too sharp, and at the same time to avoid contact lenses to other sharp things;
11, every day when you clean the lenses must be used to hand scrub the lenses;
12, different brands of contact lens care solution, can not be used interchangeably;
13, regular replacement of the preservation box of contact lenses, it is best to change once every three months;
14, contact lens care solution can not be used again after three months after opening;
15, if the contact lenses are not often worn, you should also change the care solution every other day;
16, the lenses can not be placed in physiological saline preservation;
17, if the eyes are uncomfortable, redness, must be taken down.
Selecting 7 points of care solution
Contact lens care solution is undoubtedly essential for contact lens wearers. When making your purchase, be sure to check the following contents marked on the product labeling instructions:
1). Product name;
2). Specification, dosage form;
3). Manufacturer;
4). Manufacturer's health license number;
5). Method of use and scope of use;
6). Precautions;
7). Production date and shelf life.
Note: Do not buy more than one bottle of care solution at a time. The environment in your home differs from that kept in a professional sales department and does not provide the right environment for the care solution.
See the function of contact lens care solution
(1) The contact lens care solution currently on the market can be divided into two categories according to the category without disinfecting function and with disinfecting function, and can be divided into single and multi-functional according to the function, which includes four steps of cleaning, disinfecting, rinsing, and preserving, and the one that only has one of the functions is called single-functional, and the one that has the four functions at the same time is called multi-functional. The disinfection process is a key step in ensuring the hygiene of contact lens lenses.
(2) Therefore, consumers should purchase the appropriate products according to their own needs, and should not use single-function products without disinfection as multi-function products, otherwise they will not only fail to protect the lenses, but also cause lens contamination, eye infections, and serious blindness.
What are the components of the care solution? What are the care functions of these ingredients?
The ingredients in different contact lens solutions vary slightly. In the case of multifunctional solutions, the ingredients mainly include:
(1) an ingredient that safely and effectively disinfects and cleans contact lenses, which disinfects and cleans contact lenses while minimizing eye irritation;
(2) two wetting agents that are close to tears (the wetting agent is close to tears); and (3) a wetting agent that is close to tears. close to tears (this wetting agent is also used in products to treat dry eyes), the ingredient can form a moist protective film on the eyeball to improve the comfort of wearing contact lenses, and can keep the lubrication between the eyeball and contact lenses for a long time;
(3) 4 kinds of physiological electrolytic solution and taurine, so that the contact lens care solution and the physiological environment of the human body's tears are more compatible with each other, which can ensure the health and comfort of wearing contact lenses.
For choosing contact lens care solution, many ophthalmologists now recommend the use of care solution formulated with taurine, because taurine is present in the cellular tissues of the eye, tears and other body tissues (including bones, heart and brain), and has an anti-oxidant function that ensures normal growth of corneal tissues and effectively penetrates the cellular surface to enhance the role of repairing cells. By inhibiting the oxidation and denaturation of the beneficial protein lysozyme in human tears and regulating the water content of epithelial cells, it reduces the occurrence of protein denaturation and maintains the "eco-balance" of the eye, thus effectively reducing the itching and even stinging of the eyes of contact lens wearers.
How to use the care solution
1) Consumers should read the instructions carefully.
2), pay attention to eye hygiene and personal hygiene.
3), after use, the preservation of the product should not be ignored, do not put the care solution in a humid bathroom or direct sunlight, otherwise it is easy to lead to deterioration, mold.
4), consumers should establish a concept: contact lens care solution is used to care for the lens rather than eye care.
5) If redness, pain and blurred vision are found in the eyes, users should stop using it and seek medical advice.
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