One of the downsides of aging is you often find yourself fumbling in your pocket or purse for reading glasses or holding a menu at arm’s length just to sort the mulligatawny from the minestrone. A new set of tunable glasses, rolled out at CES, is hoping to do away with those inconveniences — but early users say it still has a way to go.

Voy glasses let the wearer adjust the prescription on the fly, via a small wheel hidden in the front of the frame. Originally designed for people with presbyopia (a $3 word that’s slightly easier to confess in public than saying, “I need bifocals”), the glasses now aim for a wider audience, including drivers and athletes.

It’s an odd play in the vision space, but even the best eyeglasses can disappoint from time to time – as your eye’s strength varies slightly on a day-to-day basis. External factors from fatigue to stress to frustration at your ophthalmologist can cause patients’ corrective vision needs to vary. Voy glasses correct for that – and don’t require any electrical or battery components.

They also feature an anti-reflective coating, as well as UV and blue light protection.

The glasses are available now starting at $59 and run as high as $99. (It’s still a very wise idea to see your eye doctor annually, though.)

Using the glasses is simple enough. Turn the wheel away from the nose for more negative power (good for people who are far-sighted). Turn it toward the nose to increase the magnification. As you might guess from the design description, these aren’t the frames for you if you’re looking for something thin. They weigh 35 grams, about the same weight as a light bulb, but within norms for the industry.

This isn’t a debut for Voy. The company got its start on Kickstarter last year just barely topping the goal for the glasses with 163 backers. Early feedback has been … well, underwhelming, judging by the comments section. Backers describe the product as “plasticky and low quality” and have complained of headaches. Others called it a “waste of money” and said the “end product has more misses than hits”.

Voy, in a response to Kickstarter backers, said that “this is our first release of the product. We recognize there are many areas we need to improve. We hope our tunable lens technology can work for lot of people and help them seeing better under various conditions.”

For more of the most exciting wearable tech seen at CES 2021, take a look at our roundup here.