Bifocal Glasses Meaning: How Bifocals Work and How They Compare With Progressives
Quick answer: Bifocal glasses have two prescriptions in one lens: the main part for distance and a small segment at the bottom for reading. They are mainly used from the 40s onward, when near focusing weakens (presbyopia). The visible line gives a wide, stable reading area but no clear middle zone for computer distance, and the image can jump when your eyes cross the line. Progressive lenses offer distance, middle and near without a line but need a short adaptation period.
Choosing new glasses? Get a complete quote for frames and lenses at Vision Concern Lazimpat, Boudha-Tushal or Makalbari, with an eye test (NPR 400) if your prescription is out of date.
How bifocals work
You look straight ahead through the upper part for distance and lower your eyes to read through the segment, which has extra plus power (the ADD on your prescription).
Types of bifocal segment
- Flat-top (D-segment): the most common shape, with a straight top edge.
- Round segment: a softer-looking circle.
- Executive: the reading area spans the full lens width, useful for desk work.
Bifocal vs progressive vs trifocal
- Bifocal: two zones, a visible line, easy to get used to, no middle zone.
- Trifocal: adds a middle segment for arm's length, with two lines.
- Progressive: gradual change from distance to near with no line; more natural for computer use, but needs accurate fitting and a week or two to adapt.
Who bifocals suit
Bifocals can suit people who mainly switch between distance and reading, find progressives hard to adapt to, or want a simple, cost-conscious option. Children with certain eye-focusing or alignment problems are sometimes prescribed bifocals too.
How Vision Concern can help
Vision Concern is an eye-examination clinic and optical shop in Kathmandu with branches in Lazimpat, Boudha-Tushal and Makalbari. Its optometrists can examine your eyes, explain findings, update your glasses or contact lenses, and refer you to an eye specialist when medical or surgical care is needed.
Frequently asked questions
What does bifocal mean?
Bi means two: bifocal lenses have two focal powers, one for distance and one for near.
Are bifocals or progressives better?
Neither is better for everyone; progressives suit computer users and appearance, bifocals suit people who want a stable reading zone and quick adaptation.
Can I use bifocals for the computer?
The reading segment is often too close for a screen; trifocals, progressives or office lenses work better at computer distance.
This guide is general education and does not replace an eye examination or advice from your treating doctor.
Yes. Many visitors, particularly from Bangladesh and West Bengal (Kolkata), come to Nepal for cataract, retina, or other eye surgery at a hospital and also want new glasses, a general eye exam, or contact lenses at the same time, before or after their procedure. Vision Concern is an optical and eye-examination clinic, not a surgical hospital, so we work alongside hospitals such as Tilganga: we are happy to see you for glasses, contact lenses, or a routine check-up either side of your surgical treatment elsewhere.
No conversion is needed. Eyeglass prescriptions from Germany, France, the UK, the USA, China, Russia, and almost every other country use the same international format, SPH (sphere), CYL (cylinder), and AXIS, measured in diopters. Our opticians read this directly, so you can bring your prescription paper, a photo of it on your phone, or simply your current glasses, and we will use the same values. If your prescription is more than a year or two old, we recommend a quick, free re-check before we make your new pair.
Yes. Above roughly 3,000 metres, UV exposure increases sharply because of the thinner atmosphere and reflection off snow, and ordinary sunglasses (category 2-3) do not block enough UV to prevent snow blindness (photokeratitis). We recommend glacier glasses or category-4 sunglasses with side shields, and can fit these with your own prescription if needed. Vision Concern offers ZEISS polarized, UV400-certified sunglasses with prescription lenses, which we can prepare before you set off on your trek.