Converting a glasses prescription to contact lenses ranges from extremely simple to convoluted and time consuming. That’s because there are lots of calculations involved. But if the process involves following the same formula every time, why can’t the results for … Read More
Have you noticed that your eyes aren’t as good at seeing up close as they use to? It usually starts in the late 30s, early 40s with difficulty reading fine print but as time goes on it just keeps getting … Read More
This article explores the topic of whether or not it is possible to convert a contact lens prescription to a glasses prescription. A prescription for glasses is not the same as a prescription for contact lenses. The differences in how … Read More
The Spectacle Calculator by CooperVision is an online application that can be used to convert your glasses prescription to the corresponding contact lens parameters. It can be found directly on CooperVision’s website at https://coopervision.com/practitioner/tools-and-calculators/spectacle-conversion-calculator When I first saw this calculator, … Read More
Part 4 – The Power Cross & Advanced Conversion Charts In part 1, part 2 and part 3 of this tutorial series, you learned all about how lenses work, why prescriptions for glasses are sometimes different than prescriptions for contact … Read More
The Axis What is the Axis? As I’ve discussed in part 1 and part 2 of this tutorial series, when you have astigmatism, it means that your cornea has 2 principle curvatures in it, which requires two different lens powers in order … Read More
PART 2 – Converting The Powers In part 1 of this tutorial series, I explained how glasses help to make your vision clear, how the strength of your glasses is measured, and what the numbers on your prescription for glasses … Read More
Due to popular request from optician and optometry students, as well as regular glasses and contact lens wearers, I will be doing a comprehensive set of tutorials on how to do back vertex conversions i.e., how to convert a glasses … Read More
Realizing that the numbers in your glasses prescription are not always the same numbers that are needed for your contact lenses is an important first step in being successful with contacts. Ordering the wrong power in your contact lenses can … Read More
Welcome to Contacts Advice’s Spherical Equivalent Charts. Here you will find the Spherical Equivalent of every Sphere and Cylinder combination between Sphere values of 0 to -7.75 and Cylinder values of 0 to -3.25. The charts are based on the … Read More
What is a Vertex Conversion Chart? Vertex conversion charts are helpful tools that eye doctors, optician, para-optometric technicians, etc, use as part of the process of determining what power to use for your contact lenses. Here is a conventional vertex … Read More
When you set out to order contact lenses online, you have to come prepared with a certain amount of information. The most important piece of information is your contact lens prescription. You may have mentally checked this item off in … Read More
If you wear contact lenses, you may have noticed that the numbers on your contact lens prescription are not the same as the numbers on your prescription for glasses. No, this is not a mistake.There is a perfectly good reason … Read More
Prescriptions for glasses and contact lenses are written using certain conventions. Depending on the prescribing doctor’s training and preferences, a prescription may be written in ‘negative cylinder‘ format (the most common format), or in ‘positive cylinder‘ format. Any prescription can … Read More
Your glasses prescription and your contact lens prescription are not the same! If you are using your glasses prescription to order contact lenses online, you may be ordering the wrong power in your contacts which can lead to blurred vision, eyestrain … Read More