Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
| Characteristic | n (%) |
| The frequency of changing spectacles | |
| ≤1y | 872 (32.57) |
| 1-2y | 1276 (47.65) |
| 2-3y | 332 (12.42) |
| >3y | 198 (7.36) |
| Habits of wearing spectacles | |
| Wearing when need | 966 (36.07) |
| Wearing constantly | 1712 (63.93) |
| Duration of wearing spectacles | |
| <1y | 228 (6.51) |
| 1-3y | 562 (16.04) |
| 3-5y | 808 (23.06) |
| 5-8y | 912 (26.03) |
| 8-10y | 122 (3.48) |
| >10y | 46 (1.31) |
