The Keyhole glasses 0-2 years are designed for children with head circumference from 34 to 49 cm (340-490 mm).
If you have a doubt between 2 measures, we recommend you to take the largest
The Keyhole glasses 3-5 years are designed for children with head circumference from 50 to 52 cm (500-520 mm).
If you have a doubt between 2 measures, we recommend you to take the largest.
The Keyhole 6+ year old glasses are designed for children with head circumference from 52 to 54 cm (520-540 mm).
If you have a doubt between 2 measures, we recommend you to take the largest.