Prescription Glasses are glasses designed to correct vision issues. They come in a variety of styles in terms of strength, designs, and styles. They’re usually worn by people who have a range of problems with vision, including farsightedness, nearsightedness and presbyopia.
If you’re looking for a pair of Cheap Prescription Glasses Online, it’s important to be aware of the specifics of your prescription so you can order the right frame for you. This includes knowing the difference between single lenses, bifocals and progressive lenses. It also aids you to understand your prescription.
The Sphere of the Lens
Your prescription chart will include a number (usually abbreviated SPH) in the form of a column with a sphere, typically with a positive or negative sign. The number in the sphere represents the number which tells you the amount of power your lens will need to be adjusted in order to improve your vision. The minus sign indicates nearsightedness, meaning that you require the ability to see closer. The plus sign refers to farsightedness, which requires that you can see farther away.
The Power of the Lens
Your lens power will be measured using diopters , just like your prescription number. The higher your prescription number is, the farther it is from zero. In a single-lens prescription this number is typically located in the first section of your prescription chart.
The second number on your prescription will indicate how much power you require to align your two lenses. This is a small portion of prescriptions.
The distance between your eyes and your pupils is referred to as the PD (or IPD Pupillary Distance). Unlike a contact lens, your PD can change as you get older and so it’s essential to keep your PD updated with each pair of glasses you purchase. In certain states, eye doctors are required to provide this PD measurement based on your prescription. Other states do not.
This is a crucial measurement that is why it is recommended to get this information from your eye doctor at your next appointment. Some online retailers offer this service for an extra cost, so make sure to inquire if they offer it.
Another important measure is BVD or back vertex distance. This is the distance between your back and the cornea’s front. This can have a significant influence on the amount of lens power that your eyes receive. This is particularly important for high prescriptions, as slight changes to the BVD could result in different amount of power being delivered to your eyes than you require.
When you need to change Your Lenses:
The process to change the lens of your glasses is the same as ordering new glasses online. Your optician will examine your current glasses and send them to an optical lab where the lens will be ground and shaped according to the new prescription.
Then, you’ll select your new lens and combine it with the frame you prefer to create the perfect pair. Within 14 days after receiving your purchase, your new glasses will be delivered to you.