If you've ever been to an optometrist, ophthalmologist, or optician, you've most likely received a prescription for eyeglasses. However, understanding how to read your prescription and choosing the right lenses can be confusing. Let's walk you through the process of reading your prescription and choosing the correct lenses for your needs.
Reading Your Prescription
Your eyeglass prescription is a written statement by your eye care professional that specifies the corrective lenses needed to correct your vision. It contains a series of numbers and abbreviations that may seem confusing initially, but it's essential to understand what each means to ensure you get the right lenses for your needs.
OD and OS
The first two terms you will encounter on your prescription are OD and OS, which stand for "oculus dexter" and "oculus sinister," respectively. These terms are Latin for "right eye" and "left eye." Your prescription will list the parameters for each eye separately. Sometimes, the abbreviation "OU" may be used instead of OD and OS, which stands for "oculus uterque," meaning "both eyes."
Sphere (SPH)
The sphere (SPH) value is the primary correction for nearsightedness (myopia) or farsightedness (hyperopia) and is measured in diopters (D). A negative value indicates nearsightedness, while a positive value indicates farsightedness. The further from zero, the more severe the condition.
Cylinder (CYL)
The cylinder (CYL) value indicates the degree of astigmatism, which means that the cornea is shaped more like a football than a sphere. Astigmatism can cause blurry or distorted vision. The cylinder value is also measured in diopters and can be positive or negative. If there is no cylinder value, it means you don't have astigmatism.
Axis
The axis is a number between 0 and 180 degrees that indicates the orientation of the astigmatism. The axis is only present if there is a cylinder value.
Add
The "add" value is a measure of the additional power required for reading or close work. It is a positive number and is only present in bifocal, trifocal, or progressive lens prescriptions.
Choosing the Correct Lenses for Your Prescription
Once you understand the various parameters in your prescription, it's time to choose the right lenses for your needs. At LensFactory, we offer a range of lens materials and designs, including plastic, poly, high index, or glass lenses, as well as single vision, bifocal, trifocal, progressive, and non-Rx lenses.
Lens Materials
Plastic Lenses
Plastic lenses are the most common type of eyeglass lenses, as they are lightweight, impact-resistant, and easy to care for. They are also less expensive than other materials. However, they are thicker than other materials and may not be suitable for higher prescriptions.
Polycarbonate Lenses
Polycarbonate lenses are a type of plastic lens that is even more impact-resistant than regular plastic lenses. They are also thinner and lighter, making them a good choice for people with higher prescriptions or for children's glasses. They are more expensive than regular plastic lenses but offer better protection.
High Index Lenses
High-index lenses are made of a special material that bends light more efficiently than plastic or glass lenses. As a result, they can be made thinner and lighter, making them a good choice for people with high prescriptions who want a more aesthetically pleasing lens. They are more expensive than other materials, but they present better optics.
Glass Lenses
Glass lenses were once the most common type of eyeglass lenses, but they have become less popular due to their weight and fragility. They are still an option, though, and they offer excellent optics. They are also scratch-resistant and provide a clear image. However, they are not recommended for active people or children due to their fragility.
Lens Designs
Single-Vision Lenses
Single-vision lenses have the same prescription throughout the entire lens and are used to correct nearsightedness, farsightedness, or astigmatism. They are the simplest type of lenses and the most affordable.
Bifocal Lenses
Bifocal lenses have two prescriptions in one lens, separated by a visible line. The top portion of the lens is for distance vision, while the bottom portion is for near vision. Bifocal lenses are a good choice for people with trouble seeing objects up close or needing help reading.
Trifocal Lenses
Trifocal lenses have three prescriptions in one lens, separated by two visible lines. The top portion of the lens is for distance vision, the middle portion is for intermediate vision, and the bottom portion is for near vision. Trifocal lenses are a good choice for people who need help seeing objects at different distances.
Progressive Lenses
Progressive lenses have a gradual transition from distance to near prescriptions, with no visible line. They provide a more natural vision experience than bifocal or trifocal lenses, and they are a good choice for people who need help with both distance and near vision. However, they are more expensive than other types of lenses.
Non-Rx Lenses
Non-Rx lenses, also known as plano lenses, have no prescription and are used for fashion or as protective eyewear. They can be made in any lens material or design and can include features such as UV protection, polarization, or scratch resistance.
Choosing the Right Lens Options
In addition to the lens material and design, there are several lens options to consider when selecting your lenses.
Anti-Reflective Coating
Anti-reflective (AR) coating reduces glare and reflections on the lens surface, improving visual acuity and reducing eye strain. It also makes the lenses appear clearer and less noticeable. AR coating is recommended for people who spend a lot of time in front of a computer or under artificial lighting.
UV Protection
UV protection blocks harmful UV radiation from the sun, reducing the risk of eye damage and vision loss. UV protection is essential for people who spend a lot of time outdoors or who are exposed to UV radiation from artificial sources, such as tanning beds.
Polarization
Polarization reduces glare and improves visual clarity by filtering out light that is reflected off flat surfaces, such as water, snow, or pavement. Polarized lenses are recommended for people who spend a lot of time outdoors, especially around water or snow.
Photochromic
Photochromic lenses darken in bright light and lighten in low light, providing automatic protection from glare and UV radiation. Photochromic lenses are a good choice for people who frequently transition between indoor and outdoor environments.
In summary, choosing the right lenses for your eyeglasses is essential for maintaining good vision and preventing eye strain or damage. Understanding your prescription and the different lens options available can help you make an informed decision. At LensFactory.com, we offer a range of lens materials, designs, and options to suit your needs and budget. Whether you need single vision, bifocal, trifocal, progressive, or non-Rx lenses, we can provide you with high-quality, affordable replacement lenses.