Lenses Explaination :
Aspheric Lenses :
|
|
|
||
|
Aspheric Lenses
undistorted edge, see the thing as real
|
●Thinner ●Lighter ●Flatter |
Spheric Lenses distorted edge, distortion |
|
|
Difference between Spherical Lens and Aspherical Lens
Generally speaking, spherical lens are thick and the image through the lens will be distorted.
aspherical lens are thinner, lighter and more comfortable for wearers.
Aspherical lens have wide vision and the image through the lens
is more real and natural. Wearers will not feel tired after wearing aspherical lens for a long time.
|
|||
Optometry Data Explaination :
|
Explaination:
1.OD-RIGHT = Right Eye OS-Left = Left Eye
2.Sphere (SPH)=Spherical, is the strength of our prescription,
“+”refers to farsightedness and presbyopia, “-“refers to
nearsightedness. If “PL” or “Plano” is stated at the place of
SPH on your prescription, please enter 0.00 for this option.
3.Cylinder (CYL) = Cylindrical, is the diopters degree of the
astigmatism. This number also has “+” or “-” signs. If “DS”or
“SPH” or “spherical” or “PL” is stated at the place of CYL, it
means you have no astigmatism and 0.00 is the option
required to choose.
4.AXIS, is a number between 0 and 180 degrees, and means
the orientation of your astigmatism. There is no sign before
this number.
5.PD-PUPILLARY DISTANCE = Pupillary Distance
|
|
|
|
|
|
PD (OU), written as “64”, means the Binocular PD which is for both eyes. |
PD (OD), means the Monocular PD for the right eye, PD (OS), means the Monocular PD for the left eye. |
Thickness of the lenses depends on a few factors.
1. Prescription strength. The stronger the prescription, the thicker the lens, all else being equal.
2. Frame selection/fit. All else being equal, the larger the size of the lens, the thicker it gets (thickness proportional to size).
3. The higher the index of refraction, the less of a material is necessary to bend, or focus, the light in the same way for the same prescription. So, higher index material lenses will also reduce thickness and “Coke bottle” effect.
Helps for common discomforts.
1. New glasses
2. New Prescription
3. The change of frame shape may cause discomfort.
4. Discomfort caused by discordance of prescription and lens index.
5. Discomfort caused by the spherical lens.
