What are Varifocals lenses?
What are Varifocal lenses?
Also know as progressive spectacle lenses or progressive addition lenses (PAL) Varifocal lenses are corrective lenses used in spectacles to correct presbyopia and other disorders of accommodation.
They are characterised by a gradient of increasing lens power, added to the wearer's correction for distance prescription (refractive error)
The gradient starts at the wearer's distance prescription, at the top of the lens and reaches the full reading power, at the bottom of the lens. In practice this should allow clear point of focus to see objects at any distance.
Difference between Bifocal & Varifocal Lenses?
Bifocals have two separate zones for distance and near vision, it is easy to locate and spot both parts with a clear visible distinguishing line. The upper part of the bifocal lens is for distant vision and the lower portion is for near vision.There is no intermediate correction i.e. for computer screens, arms length distances. You will always notice the differentiating (bifocal) line when switching from far to near.
Visually, bifocal glasses show off your age and tell others that you wear reading glasses, its not that problematic if you prefer showing your age but sadly not everyone wants to tell the other person his age through their lenses.
On the other hand, varifocals do not display any such distinguishing factors. Moreover, the varifocals are divided into three parts for correcting near, distance and intermediate vision defects. The upper part of the varifocal lens corrects your distant vision, the intermediate is for computer work like reading an article online and the near portion is for distant vision. Unlike Bifocals, wherein there is a quick move from distant vision area to the reading area. When it comes to varifocals, there is a very smooth transition from one zone of power strength to the other.
Cost of Varifocals vs Bifocals
Bifocal Lenses. Been around since 1760 .Old Tech. Varifocals first showed up 200 years later!
There are many types of varifocals & a huge variation in price between different brands & designs given out by various optical retailers which can be baffling!
Varifocal glasses combine the benefits of both convex and concave lenses to correct myopia and hypermetropia in a single lens. The upper portion of these advanced glasses allows the user to view distant objects clearly, while the lower zone of the glasses let the user view close by objects. Thus, the user may feel difficulty in viewing from these double prescription glasses. It is very normal to experience distorted vision. Usually, the peripheral vision is affected along with difficulty in analysing depth perception. People may experience a little trouble while climbing the stairs, driving or walking on the footpath.
First time varifocal wearers may take more time to adapt. Whilst some put them on and have no issues adapting most take a few weeks to adapt from the change in head & eye movements- after all you are changing habits of a lifetime!
Like most product purchases you tend to get quality in line with how much you pay for it. You could get on famously with a £100 pair of good varifocals but with more expensive ones you will generally get less distortion in the periphery; wider clear areas for distance ,intermediate & near zones.
The way I look at it is, if you wear glasses full time, change them every 2 years & they cost you e.g. £365 then it costs you 50p/day ... for something you wear all day every day for 2 years!
At Glasses Outlet we use HOYA digital freeform lenses. Hoya's anti-reflective, blue control coatings come with a 2 year manufacturer's protection against coating defects.