This one is interesting and about totally useless. I cannot think of a time when I used this in my career, but it's a cool concept and an optical theory worth knowing. For this formula, focal length will always be in meters.

Lens formulaClass 10

Here at IcareLabs, we pride ourselves in making learning a priority. Our sales, marketing, and customer service teams are constantly utilizing different resources to stay up to date with current products. This allows us to share with our customers the benefits of these new products as they roll out.

Optical lens

To determine which eye the slab will need to go on, always remember that it will go on the most minus or least plus eye.

Lens formulacalculator

This formula is used for calculating the amount of prism that is being induced in a pair of lenses or to find out how much to move the OC to induce a specific amount of prism.

Derivation oflens formula

To calculate the total decentration (TD), you will want to take the patient's PD and subtract it from the frame PD (FPD).

Power oflens formula

This is the process of finding the prism at a given point in two lenses of a pair of glasses. This will involve the optical cross and finding the true power of a lens at the desired meridian. Then figuring the prism in each lens and the difference between them.

I hope that this can be a reminder to our more experienced readers and a training tool for others. Either way, feel free to print and save it as a resource. You never know when some of these formulas could come in handy.

Magnification oflens formula

This is an important formula for those who are edging stock lenses as this will let you know how large of a blank is needed for a frame. You will need to know a couple of key things before you can start:

Recently, we had the opportunity to send a handful of our staff back to school with weekly classes getting them ready to pass the ABO certification test. While I have been in the industry for well over 25 years, I went ahead and jumped at this opportunity and took the class. It is true that you are never too old to learn and I sure was reminded of how much I have forgotten over the years. The old adage of "use it or lose it" was proven to be correct for me.

Lensequation

Once you know Prentice's Rule, figuring out the amount of prism to use for a slab off is pretty simple. However, you may want to get your calculator ready.

James joined IcareLabs in 2005. He has over 35 years of optical experience and is an ABO Certified Optician. James is our go-to optical expert and loves to share his knowledge with customers. He also leads our sales and marketing team. In his free time, you'll find James enjoying the outdoors with is family; especially hunting or fishing. James' blogs have had over 100,000 views.

I figured that if I enjoyed being reminded of these formulas, maybe someone else out there would appreciate a cheat sheet with the some basic optical math formulas.

One of the key reminders for me was some of the optical formulas that we used often back in the day. With modern technology, it is easier just to plug the parameters into a program and let it do the work for us. While this is true, I do believe that knowing these formulas and knowing how to use them will make us better at our jobs. It gives us a better understanding of optical principles that we all should know.

In its original form, "Prentice's Rule" was calculated in centimeters. However, nobody uses centimeters in optical anymore so we will use a formula that will convert to millimeters.