Wash and dry your hands. Lay a soft microfiber cloth on the table to avoid scratches.

Warm the frame slightly so it flexes more easily: hold it under warm (not hot) tap water for ~20–30 seconds. Don’t use boiling water or high heat. This is a common, safe trick for hard-plastic sunglass frames.

If you use the Prescription Insert, remove it first so it’s not in the way. It clips in at the nose-bridge and is designed to be taken on/off.

Hold the glasses with the inside facing you (temples open).

Start away from the mirror corner. With your thumbs on the inside of the lens along the top rim (brow line) and your fingers pulling the frame outward, gently push the lens forward at the top-outer corner until that section “pops” free from the groove. Avoid pressing directly on the mirror area. (This push-from-the-inside, flex-the-rim method is the standard approach for hard-plastic frames.)

Work your way along the rim: once the top-outer corner is free, slide toward the nose bridge and then along the bottom edge, easing the rest of the lens out of the frame.

Check orientation (mirror on the correct side for your model). TriEye sells left-, right- and dual-mirror variants; make sure the mirror corner matches your frame.

Seat the nose-bridge edge first: align the new lens into the groove at the nose, then arc the lens into the frame.

Snap in the top rim last: with the frame slightly flexed open, press the lens inward along the top edge until it clicks fully into the groove.

Run a fingertip around the entire perimeter to confirm the lens is evenly seated—no gaps, no creaks. If anything feels tight, warm the frame again and reseat.

Re-attach the Prescription Insert (if you use one).

Clean with a microfiber cloth.

Put the glasses on and fine-tune the mirror angle per TriEye’s guidance (you should see a sliver of cheek/shoulder when set correctly).