Contact lenses are a godsend for people with visual disabilities. Were distributed in the United States in the early 1970s and has since captured the imagination of people around the world. Today there are prescription contact lenses, like contact lenses for cosmetic purposes. There are a variety of contact lenses available with different designs for various vision problems.
Soft contact lens models
There is a design very soft contact lensavailable to suit a particular vision problem. No matter if you are nearsighted or farsighted, you have astigmatism, or have a prescription for your presbyopia bifocals, your eye care professional can best contact lens design that suits your needs to recommend.
Spherical single vision contact lenses - These are the most common and popular soft contact lenses available. They take care of your nearsightedness, farsightedness and (myopia andhyperopia). As spherical single vision lenses have the same strength along the curve. The contact force is expressed in units known as diopters (D).
If the power in all meridians of the spherical contact lenses is the same, is expressed by a single number to describe the target. Single vision spherical soft contact lenses are made in the supply phases of 0.25 D. For example, if your current power is + 1.75 D lenses, the lens power following strongerwill be available to + 2.00 D.
The strength of contact lenses that correct nearsightedness is preceded by a minus sign (-) sign, while in case of hyperopia, the power is preceded by a plus sign (+) sign. The single vision spherical soft contact lenses that the power of his - just 1.50 D 1.50 diopters of myopia. Power is sometimes referred to as - 2.50 SPH, or light - 2.50.
Single Vision Toric soft lenses - These are soft contact lenses are used for the correctionastigmatism with either farsightedness and / or myopia. Astigmatism, a relatively common disease, is caused by irregularities in the cornea or lens of the eye. Usually an inherited disorder in astigmatism, the spherical normal form of the cornea or lens of the eye is elongated.
Correction of irregular shape of the cornea of the eye, these soft contact lenses have different powers in different meridians. The soft contact lenses normally run ineyes. In the case of single vision spherical lenses, no matter if the power is approximately the same meridian. In the simple case of soft toric lenses for astigmatism, the target must be kept running in my eyes because there are different responsibilities for different meridians.
This is essential for a clear consistent vision, the ability of the lens must be provided to the meridian. This is done by 'ballast' - a special system for weighing anddifferent thicknesses in different lens meridians. This causes the lens holder.
Two numbers describe the powers of single toric soft contact lenses - a sphere power (SPH) and a power cylinder (cyl). The sphere power may be preceded by a minus sign (-) sign, or a plus sign (+) sign, while the power of the cylinder is always less (-). In a recipe, the atmosphere is always written stream first, followed by the power cylinder.
The rules for toric soft contact lenses provide athird number, known as the 'cylinder' axis'. This power is always preceded by
'X' and is the latest in the recipe. This axis indicates the position of the flattest meridian of the eye - the meridian for the atmosphere that power - and the angle is measured in degrees.
The soft bifocal and multifocal lenses - These are soft contact lenses designed to correct presbyopia, hyperopia with and / or myopia. Affecting adults over the age of 40,Presbyopia is the loss of normal age-close focus.
The spherical power in the bifocal or multifocal soft contact lenses to correct nearsightedness or farsightedness. There are also one or more magnifying power for near vision. This extra magnifying power, called "add power" is for the correction of presbyopia. The "add power" as the sphere and cylinder powers in respect of prescriptions soft contact lenses are measured in diopters, and always preceded by a plus sign(+) Sign. It has a range from 1.00 to 3.00 D.
The fit of the lenses and the size of the pupils of the wearer are some of the factors that influence the performance of bifocal and multifocal soft contact lenses depends. People who use multifocal or bifocal contact lenses have a slightly reduced visual acuity than when using a single standard corrective lenses for distance vision, contact lenses and glasses for near. Yet many are willing toover the head of this vision is a bit 'less clear for the ability to read without reading glasses.
There is an alternative way of presbyopia is corrected with a single soft lenses - or spherical or toric. This technique, called monovision, soft contact lenses prescribed so that one eye is best viewed at a distance and the other eye is optimized for near vision.
contact lens wearers, uncomfortable with bifocals or multifocal find monovisionmonofocal lenses greater clarity is concerned. The main advantage of using single lenses rather than bifocals or multifocal is accessibility. The cost of the single lens is significantly lower than that of bifocals or multifocal.
Contact lens designs for keratoconus
Keratoconus - abnormal cone-shaped protrusion of the cornea of the eye - can be corrected by contact lenses with many different designs. The ophthalmologistassess the requirements of each individual to make a lens to the health of the cornea, which offers the best combination of visual acuity and comfort. Each design has its unique characteristics, and design is not suitable for all types of keratoconus.
geometry of hard lenses, usually spherical, getting the best visual result. geometries of aspherical lenses are used in the case of small to moderate nipple cones, it fits with the more normal peripheral cornea.
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