Prentice’s Rule Calculator: Induced Prism from Decentration
Calculate induced prism from decentration with Prentice’s rule. Enter lens power and decentration for the prism, or any two of prism, power and decentration to solve for the third.
Saulo Garcia
I grew up inside an optical shop. My mother likes to tell how, as a kid, I would watch eyeglasses being assembled, play with the tools, and draw on the back of service order slips. The family business taught me early what a precise measurement and work done right are worth.
I went on to spend more than twenty years as a software engineer, always keeping an eye on the optical world. Optogrid was born where the two meet: digital measurement technology (pupillary distance and fitting heights) built by someone who knows the dispensing counter from the inside.
ANSI Z80.1 Lens Tolerance Checker: Does the Job Pass?
Check a finished pair of glasses against ANSI Z80.1 in seconds. Enter the ordered prescription and the lensmeter reading, and the tool flags sphere, cylinder, axis and add as pass or fail against the standard.
Minimum Blank Size (MBS) Calculator: A Quick Formula & Explanation
This post presents the common method for estimating the minimum lens block diameter, also known as Minimum Blank Size (MBS), using the formula “Frame Bridge + Frame Width – PD + Longest Diagonal + 2 mm” widely adopted in labs and optical shops. Despite its simplicity, this method offers bench‑speed calculation and a safety margin for block cutting, though it can be imprecise for complex frame geometries.
Anti-Reflective Coating on Glasses: How It Works and Is It Worth It?
Anti-reflective coating for glasses cancels lens reflections through thin-film interference, cutting night-driving glare and screen fatigue. How it works, who benefits, what it costs, and how to clean AR lenses.
Eye Floaters: What They Are, Causes, and When to See a Doctor
Eye floaters are usually benign, but a sudden shower of new floaters or accompanying flashes of light can signal a retinal tear or detachment, a sight-threatening emergency that requires same-day evaluation by an ophthalmologist.
Double Vision (Diplopia): Causes, Types, and When It’s an Emergency
When a patient says ‘I’m seeing double,’ one question separates a correctable optical problem from a medical emergency. This guide shows optical staff how to triage diplopia and refer appropriately.
How to Measure Your Pupillary Distance (PD): Ruler, Mirror, and App Methods
Pupillary distance (PD) is the measurement in millimeters between the centers of your two pupils. To measure it yourself, stand 18 inches from a bathroom mirror, hold a millimeter ruler flat against your brow, align the zero mark over your right pupil center, then close your right eye and read the mark that falls overContinue reading “How to Measure Your Pupillary Distance (PD): Ruler, Mirror, and App Methods”
Vertex Distance Calculator: Compensate a High-Power Rx
Compensate lens power for a change in vertex distance. Enter the refracted power, the refraction vertex and the as-worn vertex, and the calculator returns the power to order.
Eyeglass Frame Measurements: The Boxing System and What the Numbers on Your Glasses Mean
The numbers stamped on a frame, such as 52□18-140, are the boxing system: eye size, bridge and temple length in millimeters. This guide decodes every frame measurement (A, B, DBL, ED), shows how they set frame PD and decentration, and how to tell whether a lens will physically fit.
How Accurate Does PD Need to Be? Eyeglass Prescription and Lens Tolerances Explained
There is a published answer to how accurate a PD, lens power and optical center have to be. ANSI Z80.1 and ISO 21987 set the tolerances a finished pair of glasses must meet. This guide gives the exact numbers and what they mean for measurement at the dispensing desk.