u/Lemonfarty

Have fun!

You have a spherical CR39 lens with a +4.00 front base and a plano backside. Given that this lens is a slice of a larger complete sphere, what is the diameter of said sphere?

This one is spicy and is a legit ABO advanced style question:

A patient is dispensed a new pair of spectacles with a prescription of +12.50 DS OU at a vertex distance of 13 mm. The lenses have a front surface power of +5.50 D, a center thickness of 10.5 mm, and are refractive index of 1.50.

The patient reports that the new spectacles produce 20% more spectacle magnification than their previous pair. The previous spectacles were fabricated using the same vertex distance, front surface power, center thickness, and lens material as the new spectacles.

What is the patients previous prescription

I'll post these every once in a while to get your brains engaged. Some of these are very similar to ABO Advanced questions

I have a lens clock that is slightly broken. When I place it on the table it does not read zero, instead it reads +0.50. I measure a lens with a front curve of +4.00 and two back curves -6.00 and -8.00. What is the Rx of the lens?

Have fun!

I figured it would be fun to see where my weak spots are. Or if you’re just curious about ABO advanced you can ask about that too!

Woooo boy this whole thing has been and adventure. From finding a great color but it feels like sandpaper. Or finding the perfect board but it doesn't have matching treads. Or everything being perfect and the cost per Sqft is more than double what we thought we'd spend. Or finding something nearly perfect but then everybody says it sucks and it's hard to work with. What about so many companies that are know for selling LVP and then their sites are just dogdoo (looking at you lifeproof) Thought this would be easy. It's kinda crazy that it's not. Can you guys point me in a direction?