Some of Vistakon’s contact lenses – such as 1-Day Acuvue for Astigmatism, Acuvue Advance and Acuvue Advance for Astigmatism - are equipped with Accelerated Stabilization Design – or short ASD. What makes this design so different is the shape of the lens. The ASD design is uniformly thin around the lens edge. This is the area that is located underneath the top and bottom eye lids. Conversely there are small areas of thickness in the area of the lens that sit between the lids.

How does this make a difference and what happens during an eye blink?  In the split second of each blink the top eye lid comes down over the cornea while the lower lid pulls in towards the nose. Furthermore the eye lid makes contact with areas of changing thickness on a lens, causing the lens to move. The more contact between the eye lid and the contact lens, the more movement.  This can give contact lens wearers a fluctuating vision.  Other lenses such as prism ballasted designs are thicker towards the bottom.  By creating this thickness differential, lens designers believe that the upper lid would squeeze the lens into position. Instead, by having a thicker area near or under the eye lid, movement is accentuated. A thicker edge means more interaction with the lower eye lid during a blink and more interaction means less stability.

Contact lenses with ASD are much thinner under each of the eye lids. This means there is less interaction before, during and after a blink. As a result, patients get less twisting movement with this lens. This is not the only advantage of this type of lens design. Because of the unique placements of the thicker areas in this design, the interaction between the ASD lens and the eye lid actually increases lens stability. During a blink the eye lid interacts with the lens in four specific areas called ‘active zones’. Because of where these 4 active zones are located, each blink squeezes the lens into place even in extreme head positions.

Should the lens be inserted incorrectly, the blinking eye lid helps to re-position the lens into place quickly. This is the real break-through of this type of lens design. When you insert the lens, only a few blinks are required to put the lens into its correct position.