OK mirror
OK lenses, also known as orthokeratology lenses, are specially designed rigid contact lenses with high oxygen permeability.
When the child wears OK lenses at night, the central cornea can be flattened, and the middle and peripheral cornea can be steepened, so that the naked eye can see clearly during the day. What's more, OK lenses can effectively delay the progression of myopia. The data shows that the effective control rate of OK lens for myopia is 35%~65%, which is one of the effective methods to control myopia.
Some parents are worried that wearing OK lenses will damage the cornea. First of all, the OK lens only conforms to the regenerative corneal epithelium. The distribution of the corneal epithelium changes during wear, but the cornea remains intact and healthy. Secondly, the change of corneal morphology of the OK lens is reversible, and once you stop wearing it, the corneal morphology will slowly return to the original state.
Defocused frame mirrors
The lenses of defocus lenses have a complex optical design, with a central optical area and a microstructured area. Through the central optical area, the child's myopia can be corrected to ensure "seeing". The peripheral area is defocused by a special optical design that inhibits axial growth and slows down the progression of myopia.
Defocus lenses are not suitable for all children. Before fitting, your child will need to undergo a series of professional eye and optometry examinations. The processing requirements of lenses are also very strict, such as strabismus, binocular vision dysfunction, anisometropia, large astigmatism, etc., special caution should be exercised when fitting.
Nowadays, many children use their eyes more at close range, so the defocus lens can only achieve the effect of making the power rise a little slower.
Multifocal soft mirrors
Multifocal soft contact lenses, also known as multifocal soft lenses, are daily wear soft contact lenses with a special peripheral defocus design. It has been found that multifocal soft lenses can effectively delay the growth of myopia and the axial eye, slow down the progression of refraction by 20~30 degrees per year, and slow down the growth of the axial eye by 0.1 mm per year, the effect is similar to that of orthokeratology lenses, and the wearing comfort is good. Therefore, the Asian Consensus on Myopia Management and others list multifocal soft lenses as one of the effective means of myopia control.
Therefore, multifocal lenses are especially suitable for patients who are young, corneal flat, mild trichiasis, etc., who are not suitable for orthokeratology lenses.
Source: Public Health magazine