What is the difference between single vision and varifocal?
Although both single vision lenses (uniform vision lenses) and varifocal glass lenses are prescription glasses, they are poles apart when it comes to comparing pros and cons. It is the whole sole decision of the optometrist or ophthalmologist, whether you need a single vision glass lenses or varifocal glass lenses.
Single vision lenses contain only single power in the entire lens area and can correct anyone of the refractive vision defect. In this case, the whole lens is used to correct presbyopia, hypermetropia, myopia, astigmatism or prism eyes. The single vision lens carries a specific power strength according to vision defect and is either in ‘positive’ or ‘negative’ figures. For correcting presbyopia and hypermetropia (farsightedness) disorders, the magnifying single lens is convex in shape and power ranges from +0.75 dioptres onwards. Similarly, for myopia (nearsightedness) a concave shape lens with power strength of -0.75 dioptres is required. Therefore, single vision lenses are apt for people who have only one refractive error in the eyes or who use only one pair of glasses for most of the time. If most of your day is spent driving, playing or outdoors where reading is not required then a single vision lens is a good option. Also, if you work or spend most of the time reading, doing needlework, jewellery designing, medical practitioner etc. then wearing single-vision reading glasses are suitable. But viewing distance objects while reading glasses are on or vice versa becomes troublesome for eyes to focus. Single vision lenses are less expensive comparatively and eyes can effortlessly focus on objects.
However, if eyes suffer from two refractive disorders, say hypermetropia and myopia both; or presbyopia and myopia simultaneously, then you have two choices. First, you can buy two single vision prescription glasses corresponding to both distance vision and reading glasses and keep wearing and removing glasses repeatedly. Alternatively, free up yourself from frequently switching between reading glasses and distance glasses, give comfort to your eyes by just one pair of varifocal glass lenses. Varifocal lenses or transition lenses consists of three refractive focal points, without any distinctive line as in case of bifocal glasses. The major upper part of the varifocal glasses lens is for distance vision correction, while the mid part is for correcting intermediate vision and the lower part of the lens is for closer vision disorder correction. Therefore, the entire varifocal glass lens ranges from various power strength varying from ‘negative’ to ‘positive’ dioptres i.e. from a distance, intermediate distance and reading mode. Since all the power strengths are embossed in one lens, it becomes comfortable to view car parked outside, computer screen along with grazing magazines from a sole pair of varifocal glass lenses.
Specscart’s home trial glasses can show the real picture of how transitions glasses work. It has been observed that some user takes more time to adapt to varifocal glasses and faced peripheral distortions.
Though varifocal glass lens comes at an expensive price as compared to single vision lenses, considering the fact that a substantial amount of money is saved by not buying two glasses separately for correcting hypermetropia and myopia as in the case of single vision, instead of one pair of varifocals are worthwhile. Buying cost and maintaining two pairs is quite a disturbing task in itself, whereas the varifocal glass user is relieved and can enjoy carrying just one pair of wonders. Interestingly, old or existing frames of single vision lenses can be used to reglaze glasses for replacing with varifocal lenses at Specscart with express glasses delivery.
