(of a pair of glasses) having lenses with three parts with different focal lengths.
- ‘One analysis reports that neck pain experienced by middle-aged patients often coincides with their first prescription for bifocal or trifocal glasses.’
- ‘A bifocal lens corrects both far and near vision, while a trifocal also has an intermediate zone.’
- ‘Additionally, where bifocal or trifocal lenses are not desirable, disposable lens shields and ‘press-on’ lenses in the upper and/or upper-central regions of the lens have been proposed.’
- ‘And trifocal contact lenses are placed a little bit higher in such a way that the area for intermediate zone is on the pupil of the eye.’
A pair of glasses with trifocal lenses.
- ‘In addition to this, those glasses were extra-strength double-duty army trifocals or something.’
- ‘And if you wear bifocals or trifocals, keep in mind that you may have a tendency to tilt your head backwards so that you can see through the lower portion of your glasses.’
- ‘Older aviators and farsighted aviators may require trifocals, which have two sets of near - vision refractive glass to focus on intermediate and near distances.’
- ‘Scopes also help mature shooters continue in the sport longer, he said, because finding iron sights through bifocals and trifocals can be challenging.’
- ‘I paid $100 American for blended trifocals, and they are the best glasses I have ever owned.’
We take a look at several popular, though confusing, punctuation marks.