This Is The Best Cataract Lens For Night Driving
Cataracts really impair night time driving. It’s no surprise than that some desire to have the best possible night time vision after cataract surgery.
And this can be done!
After the cataract is removed, it is replaced with a new artificial lens. But not all artificial lenses are the same. Different lenses have different strengths. Some lenses are designed to get out of glasses as much as possible. But on the other end of the spectrum, other lenses are designed to provide the clearest far away distance vision possible - vision that allows for the best night driving vision.
The easy answer is that the best cataract lens for night driving is what’s known as a monofocal or single focus lens. But amongst the different monofocal lenses the answer goes much deeper; some will actually optimize distance vision more than others.
But don’t worry, we’ll cover it all.
Monofocal Lens Is The Best Choice
When we are young, our own natural lens is special. With our vision corrected with glasses, contact lenses or surgery, it is capable of not only focusing off in the distance, but also can change shape to focus up close as well. It’s a real marvel.
Sadly, this cool feature doesn’t last. During our 40s, this lens weakens and loses the ability to change shape. This locks the lens into a single focus. When vision is corrected, the lens can only focus in the distance. Reading up close requires reading glasses or progressive glasses.
And this continues all the way up to when this lens becomes a cataract, is removed during cataract surgery and replaced with an artificial lens.
This artificial lens is made from a special plastic called acrylic or silicone. This plastic also can’t change shape, so it can’t change focus. By default, it is a monofocal or single focus lens. Like the weak natural lens, it will require glasses (typically for reading).
However, some people desire to get out of glasses. So more advanced lenses have been developed that allow for simultaneous distance and reading vision. But again, these lenses don’t change shape. So instead, fancy optical tricks are used to focus light. These tricks work to get out of glasses but do come with a trade-off: an increase in the amount of halos and starbursts.
Learn more at Your Complete Guide Of Lenses For Cataract Surgery
Halos in vision; generated image courtesy of VisionSimulations.com
If the goal is to have the purest sharpest night time vision possible, having halos and starbursts isn’t the answer. But if the goal is to have the most freedom from glasses, having less than perfect night time vision must be tolerated. Fortunately, with modern lenses, the increase of halos and starbursts are minimal and the eye also adjusts over time.
Due to the simple fact that monofocal lenses don’t apply any optical tricks, they will provide the purest distance night driving vision of all the lenses.
Side Note: Prescription must be corrected for optimal vision
If you’ve worn glasses before, you already know that putting on your glasses sharpens up your night driving vision.
The same goes for after cataract surgery. Vision must be focused perfectly for the distance to get the best night driving vision. Any eye prescription must be corrected with glasses.
Fortunately, cataract surgery changes the prescription of the eye and often improves distance vision. Many people after cataract surgery have no or minimal eye prescription remaining.
But, to get the optimal results, astigmatism must be corrected at the time of surgery with a special toric monofocal lens; or corrected afterwards with glasses. And any residual prescription that may exist must also be corrected with a pair of glasses.
Some Monofocal Cataract Lenses Optimize More Than Others
If you want great night driving vision, you can’t go wrong with just going with any ole monofocal lens. That’s the easy simple answer.
But we don’t need to stop there.
The cornea at the front of our eye does much of the work of focusing light into our eye. But the cornea isn’t perfect. It induces a particular distortion in our vision (to a small degree).
Light that enters the edges of the cornea don’t focus at the same spot as light that enters the middle of the cornea. This creates the distortion known as spherical aberration.
In high amounts, spherical aberration can blur vision as well as create additional halos around lights at night time. So, spherical aberration isn’t great for night time driving.
So, to optimize vision further, most artificial monofocal cataract lenses are designed to avoid additional spherical aberration or even decrease the amount from the cornea!
Reducing the spherical aberration to zero gives the best chance of having the clearest and best night driving vision.
There are three major monofocal lens manufacturers in the United States. Each of these affects spherical aberration by a different amount:
It turns out, the average amount of spherical aberration the cornea causes is +0.27. So going by averages, the best cataract lens for night driving for most people would be the Tecnis lens by Johnson & Johnson.
But not everyone will have +0.27 of spherical aberration in their cornea, and picking lenses based upon individualized cornea measurements is the best way to eliminate this distortion in vision.
Theoretically, this works great.
Though in practice, it’s a little harder to statistically measure a noticeable difference between different monofocal lenses. In a large study comparing two lenses, no real world difference in driving vision appears.
Side Note: Spherical aberration isn’t all bad
If the goal is the best night driving vision, then the goal is to eliminate distortions from spherical aberration. But there are some subtle benefits to not eliminating spherical aberration completely.
Spherical aberration will actually slightly improve the range the eye can focus. This means improved computer and up close vision. Not enough to get out of glasses, but still small amounts that some may find helpful.
Honorable Mentions, Extended Depth Of Focus Lenses
Let’s explore another category of lenses. Perhaps you want want a little of both - pretty good night vision but also some reduced need for glasses. Well, these lenses can meet that balance.
Advanced lenses such as trifocal or multifocal lenses simultaneously redirect light for distance and up close reading vision. This leads to the increase in halos and starbursts. Not ideal when the goal is the best night vision.
But there is a different type of advanced lens.
Extended depth of focus lenses are a type of lens which instead of using optical tricks to redirect light, these lenses bend light to cover a greater range of vision. This significantly reduces the amount of halos and starbursts to improve the night time vision. But this comes at the expense of being able to completely get out of glasses for reading.
The best of these lenses for night driving is the Eyhance by Johnson & Johnson. Technically this lens is more of a “Monofocal+” rather than an extended depth of focus lens. It has a slightly better range than a monofocal lens but will still require glasses for computer vision and for reading vision. But for night driving, these cataract lenses compare very well to the Tecnis for overall night time vision.
The Vivity by Alcon on the other hand is a true extended depth of focus lens. It allows for great distance vision and computer vision and only requires glasses to read up close. While it does have slightly more halos than a monofocal lens, the Vivity does provide a great balance between good night driving and getting out of glasses.
For the very best night driving after cataract surgery, look no further than a monofocal lens. These lenses eschew optical tricks to provide the clearest possible vision. And in fact, certain monofocal lenses can go the extra mile and eliminate distortions coming from the cornea to improve things even further.
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