Most patients walk into our clinic with a single goal: to see the 20/20 line on the eye chart. In ophthalmology, we call this the “Quantity” of vision (Visual Acuity). It measures how small a letter you can identify in a high-contrast, well-lit room.
But real life isn’t a high-contrast, well-lit room. It’s driving in the rain at night. It’s reading a menu in a dim restaurant. It’s looking at a computer screen for 8 hours.
This is where the “Quality” of vision comes in. And clinically, “quality” is determined by something most patients have never heard of: High-Order Aberrations (HOAs).
The Night Vision Problem
Have you ever spoken to someone who had laser eye surgery 15 or 20 years ago? They might tell you their vision is “perfect,” but they struggle with glare or halos around streetlights at night.
This was a side effect of older laser profiles. While they successfully corrected the Low-Order Aberrations (Myopia and Astigmatism), they often induced High-Order Aberrations (specifically Spherical Aberration and Coma) in the process.
Think of it like a camera lens: an old lens might be in focus, but the edges of the photo are fuzzy or distorted.
The SmartSight Nova Difference: Managing the “Aspheric” Shape
At Lions Laser Vision, our transition to the Schwind ATOS platform (SmartSight Nova) was largely driven by its ability to manage these optical imperfections.
The cornea is not a perfect sphere; it is aspheric (it flattens slightly towards the edges). Older lasers tended to flatten the center of the cornea too aggressively, turning this natural prolate shape into an oblate (flat-top) shape. This flat-top effect is the primary cause of night-time glare and reduced contrast sensitivity.
SmartSight Nova uses an Aspheric Ablation Profile. It preserves the natural curvature of your cornea’s periphery. By maintaining the eye’s natural Q-value (asphericity), we can correct your prescription without degrading the quality of the image entering the eye.
The Role of “CenTrax” in Astigmatism
A second major factor in visual quality is Coma – a specific aberration that looks like a comet tail on lights. Coma is often caused when a treatment is slightly decentered.
If a patient has significant astigmatism, even a microscopic misalignment of the laser can induce Coma. SmartSight Nova utilizes CenTrax technology, which tracks your eye on the Visual Axis (what you actually see through) rather than just the pupil center. It also compensates for Cyclotorsion (the rotation of your eye when you lie down).
20/20 is just the starting line. By managing High-Order Aberrations, we aim to give you great vision – vision that is not just sharp on a chart, but crisp in the real world, day or night.
