All About the Blink
One thing noted by many practitioners with the original Ultra lens was that compared to other lenses on the market, Ultra exhibited much less vertical movement with blink. As recently as the early 2000s, doctors were touting the traditional mindset that a soft contact lens should exhibit 1 mm of movement with every blink. But pivotal contact lens studies in 2009 and 2014 have greatly changed our understanding of comfort and lens dynamics. On a normal eye, blink motion mechanics predict 0.3 mm of movement would be ideal for limiting eyelid interaction and corneal nerve sensitivty at the delicate limbal region (the area where the white of the eye and the cornea meet), and that's backed up by patient comfort surveys where anywhere between 0.1 mm and 0.4 mm movement was graded as most comfortable in patient wear. We do need some movement to promote tear film exchange under the contact lens, for both comfort and ocular surface health, but much less movement than we once thought is necessary to get this dynamic!
Besides comfort, vision is greatly affected by lens movement and no population of lens wearers sees a larger impact from this than those with astigmatism. All soft contact lenses for astigmatism are weighted in design, so that the 2 different powers in the contact lens will align properly with the 2 different meridians on the patient's eye for best vision. If the contact lens moves excessively, the power meridians also move from their ideal alignment with the cornea, resulting in blur. Imagine every time you blink, move your eyes quickly, or rub your eyes that your vision goes out of focus. For many astigmatism contact lens wearers, that's a normal part of their day. Combating movement became a key focus of the design time at Bausch and Lomb on this lens, and to maximize their chance for success, they really started to look at just how complicated a simple blink can be.
Watch how the lower lid rotates inwards and upwards as the person blinks. Also interesting to note is that this person doesn't fully close their eye when they are blinking (called an incomplete blink) - a common cause of dry eye and blurry contact lens vision!
Every time we blink, the contact lens is not just moved vertically by the eyelids, but rotationally as well. The lower eyelid rotates up and in towards the nose as it moves to meet the upper eyelid during a blink. That rotational force can easily shift contact lens alignment, and minimizing the amount the lens moves with the force of the eyelids and maximizing how quickly the lens returns to its ideal location is essential to success. The initial reports show amazing results for stability in Bausch and Lomb's Ultra for Astigmatism; 94% of patients experienced 5 degrees or less of rotation at their initial contact lens dispensing appointment. In my own experience as a clinician, it's quickly become a problem-solver contact lens for me in meeting the needs of my patients reporting inconsistent vision or having difficulty with lens rotation in their current contact lenses.
The Ultra for Astigmatism lens has an alignment marking at 6 o'clock, and a smaller indicator marking that displays what axis the astigmatism correction is being delivered to. |
The Lens Details
Base Curve: 8.6 mm
Diameter: 14.5 mm
Power range: plano to -6.00 in -0.25D steps with astigmatism -0.75 through -2.25 in -0.50 steps
plus powers are slated to be available in the near future
Cylinder Axis: 0 to 180 in 10 degree steps
Oxygen Transmission: 163 Dk/t for a -3.00 lens
Have you tried Ultra for Astigmatism? Please share your experience as a wearer or as a prescribing clinician!
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