Minimum expiry date.
18 months from date of purchase
The maximum time of wearing lenses, after which you need to replace them.
Lens intended to be worn daily or extended wear schedule for a period of 30 days.
Lenses wear for a few dozen hours a day. Removing it while you sleep.
Lenses can be worn without removing it. All the time (during the life span, see Modality), day and night, even during sleep. After the end of the life span lenses must be replaced.
The same power.
-6,50D to -12,00D (0,50D step),
-0,25D to -6,00D (0,25D step),
+0,25D to +6,00D (0,25D step),
+6,50D to +8,00 (0,50D step)
|Base Curve (BC)|
|Oxygen permeability (Dk/t)|
It indicates the amount of oxygen which passes through the lens. The oxygen permeability is an key indicator of the lens material. It determines how much oxygen (which is necessary for proper performance) receives a cornea of our eyes. The higher the value, the better. Dk/t is common used and it states: the Dk per thickness of the lens. Usually for a lens at -3.00D, which makes it easier to compare different lenses brands. Ranges from 10-20 Dk/t to over 170 Dk/t.