Fix loose, tight or uneven sunglasses made from Mazzucchelli M49 acetate

Hyesun sunglasses are made from Mazzucchelli M49 acetate, a high-quality, plant-based material that’s both durable and designed to be more sustainable than traditional plastics. M49 is a cellulose acetate that includes a plasticiser of vegetable origin, making it a more eco-conscious choice without compromising on strength or flexibility.

Because of the way this material responds to warmth, your sunglasses can be gently adjusted at home if needed. Whether they’re feeling a little loose, tight behind the ears or slightly uneven, these simple steps should help improve the fit.

What You’ll Need

• A bowl of hot tap water (not boiling)

• A clean towel

• Your Hyesun sunglasses

• Optional: a mirror to check the fit

To adjust the arms (for a firmer or looser fit):

1. Warm the ends of the arms
Dip just the curved ends of the arms, the part that sits behind your ears, into hot tap water for about 30 seconds. Keep the lenses out of the water.

2. Gently reshape
Once the ends are warm to the touch, hold the sunglasses steady and gently bend the arms:

• Downwards if they feel loose or tend to slide forward

• Upwards if they’re feeling too snug behind the ears

Adjust both sides as needed, taking care to make small, even changes.

3. Cool and check the fit
Let your sunglasses cool on a towel, then try them on. If the fit still needs improvement, you can repeat the steps.

To adjust uneven or crooked fit:

If your sunglasses sit higher on one side or feel off-balance, that can often be fixed with a small adjustment.

1. Identify the uneven side
Put them on and look in the mirror to see which side sits too high or low.

2. Warm the temple corner
Soak the part where the arm connects to the front of the sunglasses in hot water for 30 seconds. Keep the lenses dry.

3. Gently bend
Support the sunglasses with one hand, and with the other, adjust the arm at the corner.

• Bend the arm down slightly if it’s sitting too low

• Bend it upward slightly if it’s sitting too high

Cool and test again. Even a small change can make a big difference.

A note on material care

Mazzucchelli M49 acetate is a plant-based material that becomes flexible when warm. This allows for at-home adjustment, but it’s important to avoid over-bending. All changes should be small and gentle. If you’re unsure, feel free to contact us first.

If you’d like to read more about the material we use, you can find information on Mazzucchelli’s M49 acetate here.

If your sunglasses still don’t feel quite right after adjusting, or if you have questions, just reach out. 

— Soojee