Glasses
Table of Contents
Who needs glasses?
Eventually, everybody. A young person with normal vision is able to see clearly near objects (e.g. read fine print) as well as objects far away in the distance. As we grow older, the ability to see near objects decreases (presbyopia). Even people born with normal vision, once they reach 40 to 45 years of age, will require vision correction to read.
Reading glasses
- Correct near vision only.
- Relatively inexpensive.
- Can be bought over-the-counter
- Must put them on when doing near work and remove them to see at distance.
- Inconvenient if your work requires frequent change between near and far gaze (bank teller, salesperson, secretary, etc.)
Bifocal glasses
- Correct near vision (bottom portion) and, when necessary, also distance vision (top portion).
- If your distance vision is normal, the top portion is plain glass (no prescription).
- More expensive than reading glasses.
- Rarely misplaced or forgotten because they are worn continuously.
- Need time to get used to them.
No-Line bifocal glasses
- Nearly invisible separation between the upper and lower portions.
- Work the same way as bifocals.
- Cosmetically pleasing.
- More expensive than bifocal glasses.
- Also known as “progressive lenses”
Trifocal glasses
- Top part is for distance, bottom part for reading and middle part for intermediate viewing
- Suggested for people who need to see clearly charts or papers anywhere on the desk (accountants, architects, typists, pianists, etc.)