All-round correction of refractive errors (including myopia, hyperopia and astigmatism) means providing patients with all refractive solutions, including.
1.Frame glasses
2.Soft contact lenses
3.Rigid contact lenses (RGP)
4.Keratomileusis
5.Excimer laser
6.IOL implantation in the anterior chamber of the crystalline eye
7.Posterior chamber IOL implantation for crystalline eyes
8.Clear lens removal + IOL implantation
Each refractive correction method has its own advantages, and what works well for others may not be suitable for you. The advantages and disadvantages of various refractive correction methods are described below.
I. Frame lens: suitable for all people who can fit
Advantages:
a, is the safest of all refractive correction programs
b, a variety of prices, styles vary
c, easy to replace
Disadvantages:
a. Small field of view
b, large aberration
II. Soft contact lenses
(A) Historical background
Soft contact lenses were invented in 1961 by Czech chemist Otto Wichterle, and have become one of the most popular types of lenses today because they are more comfortable to wear.
(B) Material
A hydrophilic material is used, usually a hydrophilic synthetic polymer compound, made of hydrogel or silicone hydrogel polymer.
The water content is divided into low (<30%), medium (30%-60%) and high (>60%). The high water content makes the lens soft and flexible, allowing oxygen to pass through the lens into the cornea, making it more comfortable to wear and without any noticeable foreign body sensation during initial use. However, because it is a soft material with water content, it can be easily contaminated or moldy, so it must be strictly disinfected.
(iii) Features
Comfortable to wear is the most important feature. The lenses are large (12.5-14.5mm) and fully cover the cornea, so it is not easy for dust and foreign objects to enter the eye, and it is not easy to displace and fall off, so it is ideal for wearing during sports activities.
(D) disadvantages
1, soft contact lenses block the cornea breathing, easy to cause hypoxia.
2, because the lack of oxygen can lead to corneal thinning, long neovascularization and other complications. Wear soft contact lenses for 10 years, 20-year-old eyes can age to 60 years old, soft contact lenses are potentially harmful.
3, easy to adsorb dirt.
4.Short life span of use.
5. Wearing soft contact lenses leads to sluggish sensation.
In short, soft contact: suitable for adaptable people.
Advantages:
a, convenient and comfortable
b. Low price
c, easy to replace
Disadvantages:
a, low oxygen permeability easy to cause infection, dry eyes
b, wear time is short, need to alternate with frame lenses
Three, rigid contact lenses
(a) What are hard contact lenses?
Rigid contact lenses, also known as RGP, human eyes need oxygen to maintain health, the eyes directly from the air to take in oxygen, if the eyes lack of oxygen, will lead to corneal edema, corneal neovascularization and other eye diseases. Highly oxygen permeable and breathable hard lens material PAMBA contains polymers such as silicon and fluorine, which can greatly increase the amount of oxygen passing through. It improves oxygen permeability compared to soft contact lenses, while ensuring that the material is firm and has good wettability and anti-sedimentation properties.
(B) RGP lens advantages
1, good physiological solubility, so that long-term wear RGP lenses are less likely to cause corneal hypertrophy and edema.
2. High oxygen permeability, less likely to cause hypoxia and dry eye and no change in corneal endothelial cell count.
3, can prevent myopia or astigmatism deepening, vision correction effect is better than soft contact lenses.
4. Simple maintenance and long service life; with proper care, lenses can last up to 2~3 years.
5, long-term use of lenses is inexpensive.
6, long-term use can maintain the physiological health of the cornea, high security.
7, because of wearing soft contact lenses and long-term lack of oxygen, eye congestion or lead to neovascularization, dry eyes, poor vision correction, eye health can be changed to RGP lenses.
8. According to domestic and international data, RGP lenses can effectively control the growth of myopia in adolescents.
(iii) Description of the adapted groups
1. Adequate oxygen supply can guarantee the health of the cornea of the eye. Suitable for.
(1) People with high refractive error.
(2) People with astigmatism up to 2.50D who cannot be fitted with toric lenses.
(3) Long wearers and those who wear them for long periods of time.
(4) Those who are not suitable for soft contact lenses due to stubborn lens deposits or inflammation.
2, in special cases, the good corrective vision performance of hard contact lenses, can correct.
(1) Patients with mild cone corneas.
(2) Patients with aphakic eyes (those who cannot implant IOLs after cataract surgery)
(3) Patients with mild dry eyes
3. The adaptation period is slightly longer than that of soft lenses, around 1 to 2 weeks.
In conclusion, RGP (high permeability rigid corneal contact lens): suitable for those who can be fitted.
Advantages.
a. High oxygen permeability is less likely to cause dry eye and infection
b. Obviously improve the quality of vision
c. Can correct astigmatism
Disadvantages
a, eye fitting is more complicated
b, poor early fitting sense
c, price and maintenance costs are relatively high
Fourth, keratomileusis: suitable for myopia 600 degrees, astigmatism 1.5D or less.
Advantages.
a. Short-term improvement of naked eye vision
b, easy to use, good safety, reversible
c, has a certain inhibitory effect on myopia
Disadvantages.
a. Strict fitting and complicated replacement
b, price and maintenance costs are high
Excimer laser: suitable for myopia, myopia <0.5D per year within two years, hyperopia and astigmatism less than 600, over 18 years old.
Advantages.
a. Good safety
b. One-time correction
c. Highly predictable and accurate postoperative visual acuity
d, good stability
Disadvantages.
a, irreversible
b.Higher price, need to overcome psychologically
Excimer laser is a kind of ultraviolet light, which is a cold laser, does not produce heat and cannot be absorbed by other tissues, and some studies have proved that the nearest corneal endothelium to the operated area has no loss after surgery. The excimer laser breaks the chemical bonds between corneal molecules through photochemistry, resulting in the vaporization of corneal tissue with only a 0.3-0.8 micron impact on the surrounding tissue. Each pulse of the laser cuts 0.2 microns of corneal thickness, requiring a precise cut of only 10-13 microns per 100 degrees of myopia. Excimer laser myopia correction is an external eye surgery, and the surgery does not have any effect on the tissues inside the eye.
VI. IOL implantation for crystalline eyes: Suitable for high and super high myopia.
Advantages.
a. Significant improvement in visual acuity and visual quality
b. Good safety and reversibility
c. It has a certain inhibitory effect on myopia
Disadvantages.
a, strict examination
b.Higher price
c. Internal eye surgery
VII. Clear lens removal + IOL implantation: Suitable for those who are older or with cataract
Advantages.
a.Low price
b. Double lens implantation can solve the extreme height
Disadvantages.
a. Poor post-operative adjustability
b. High risk of inner eye surgery
c.Imprecise vision correction