Johan Square Sunglasses

The Johan Square Sunglasses from Le 31 offer injection-molded polarized polycarbonate lenses that naturally block 100% UV up to 400nm, weigh half as much as glass to reduce nose pressure, but require careful maintenance: periodic screw tightening, two-hand removal, rinsing and blotting with microfiber, and storage in a rigid case to prevent UV fading and heat warping above 50°C.

Polarization durability

Polarizing film is injection-molded into the lens, not a surface coating.

Why this is supported

Research on the lens construction reveals:

The polarizing film is encapsulated within the plastic during injection molding rather than adhered as an external layer, permanently sealing it against peeling or delamination and maintaining consistent glare-cutting performance for the usable life of the sunglasses.What polarized lenses mean at this price — bonded_polarized_layer

This confirms the polarizing layer is embedded, not coated.

Lens weight

Plastic lenses weigh roughly half as much as glass, reducing nose pressure.

Why this is supported

Catalog verified the weight advantage:

Plastic polarized lenses weigh roughly half as much as comparable glass lenses, contributing to an overall low frame weight that allows the Johan sunglasses to be worn for hours without nose-bridge pressure—a comfort edge that matters for daily outdoor use.What polarized lenses mean at this price — lightweight_lens_impact

This lighter weight enhances comfort for long wear.

UV protection

Polycarbonate lenses inherently block 100% of UV up to 400nm, no coating needed.

Why this is supported

The lens material provides inherent protection:

Polycarbonate—the most common lens material in this price bracket—naturally absorbs 100% UV radiation up to 400nm without a surface-applied coating, so the full-spectrum protection in the Johan frames remains intact even if the lens develops light surface wear.What polarized lenses mean at this price — inherent_uv400_protection

This means UV protection is scratch-resistant and does not degrade with time.

Hinge maintenance

Periodic screw tightening and two-hand use prevent hinge loosening.

Why this is supported

The press-fit metal hinges on the plastic frame can loosen over time.

a periodic one-quarter turn with a jeweler's screwdriver keeps the temple arms from developing playDurability and care of the plastic frame — hinge_reliability

and using both hands when donning and removing the glasses ensures even force distribution.

always using both hands to put on and take off the glasses distributes the force evenly and maintains the frame's geometryDurability and care of the plastic frame — structural_care_during_donning_removal

UV fading

Storing in a rigid case prevents UV fading of dark plastic frames.

Why this is supported

According to research on UV-induced fading of plastic frames,

The colorant in dark plastic frames is vulnerable to UV degradation, which can fade the charcoal or brown hues to a chalky gray within a single summer of unshielded outdoor exposureDurability and care of the plastic frame — uv_induced_fading

To prevent this, the same research states that

storing the sunglasses in a rigid case when not in use blocks UV and dramatically slows the fading processDurability and care of the plastic frame — uv_induced_fading

Heat damage

Frame can warp above 50°C, mitigated by case storage away from sun.

Why this is supported

The thermoplastic frame of the Johan Square Sunglasses is susceptible to heat damage. Research states that

exposure to temperatures above about 50°C (common inside a parked car on a sunny day) can cause the frame front to warp and alter the lens alignment, potentially allowing lenses to pop outDurability and care of the plastic frame — heat_damage_threshold

. To prevent this, the same source advises that

keeping the sunglasses in a case and away from direct sun when not in use eliminates this riskDurability and care of the plastic frame — heat_damage_threshold

.

Frame care

Rinse the plastic frame after active use to prevent permanent residue and scratches.

Why this is supported

Durability and care guidance explains that

Salts from sweat and chemicals in sunscreen and insect repellent can corrode the frame's surface, leaving a sticky residue or pitted texture that is irreversibleDurability and care of the plastic frame — sweat_and_sunscreen_effects

. The recommended prevention is

rinsing the frame with fresh water and mild soap after each wear in hot or active conditions prevents the buildup of damaging residuesDurability and care of the plastic frame — sweat_and_sunscreen_effects

. Additionally, to avoid micro-scratches,

rinsing the frame under water to float debris off, then blotting dry with a microfiber cloth, preserves the original satin or gloss finish for yearsDurability and care of the plastic frame — cleaning_to_avoid_micro_scratches

.

Cleaning

Rinse under water, then blot with a microfiber cloth to avoid scratches.

Why this is supported

To avoid micro scratches on the plastic frame, the proper cleaning method is to rinse it under water first, then blot dry. The care guide states:

rinsing the frame under water to float debris off, then blotting dry with a microfiber cloth, preserves the original satin or gloss finish for years.Durability and care of the plastic frame — cleaning_to_avoid_micro_scratches

Handling

Removing sunglasses with both hands prevents permanent hinge misalignment.

Why this is supported

One-handed removal applies uneven force to the hinge, gradually stretching the plastic mounting point. A care guide for the Johan sunglasses advises

always using both hands to put on and take off the glasses distributes the force evenly and maintains the frame's geometry.Durability and care of the plastic frame — structural_care_during_donning_removal

Using both hands thus prevents permanent hinge misalignment and loosening.

Storage

Store in a rigid case to protect from UV fading and heat warping.

Why this is supported

Prolonged exposure to UV radiation can fade the charcoal or brown frame color to a chalky gray, and temperatures above 50°C can warp the thermoplastic frame. A care guide states that

The colorant in dark plastic frames is vulnerable to UV degradation, which can fade the charcoal or brown hues to a chalky gray within a single summer of unshielded outdoor exposure; storing the sunglasses in a rigid case when not in use blocks UV and dramatically slows the fading process.Durability and care of the plastic frame — uv_induced_fading

Additional guidance warns that

Because the plastic frame is thermoplastic, exposure to temperatures above about 50°C (common inside a parked car on a sunny day) can cause the frame front to warp and alter the lens alignment, potentially allowing lenses to pop out; keeping the sunglasses in a case and away from direct sun when not in use eliminates this risk.Durability and care of the plastic frame — heat_damage_threshold

So storing in a rigid case protects against both fading and warping.