Blog | Optical Industry Insights, Guides & Tools for Opticians

A dispensing pupillometer is an optical instrument that measures interpupillary distance (PD) by projecting a coaxial light source onto the cornea and aligning crosshairs with…

Can a pupillary distance app measure PD accurately? See how PD apps work, how they compare to a ruler and pupillometer, and how to measure your PD with a phone.

Short answer: The average pupillary distance for adults is roughly 62 mm, with men averaging about 63.6 mm and women about 61.1 mm; the normal…

Bifocals have two discrete focal zones separated by a visible segment line. Progressives eliminate the line and add a continuous power gradient through distance, intermediate, and near zones. Neither is universally better: the right choice depends on the wearer’s visual tasks, adaptation tolerance, and ADD power.

Heterochromia means having differently colored eyes or color variation within one iris. Learn the 3 types, genetic causes, warning signs, and common myths.

Yellow eyes are a visible sign of jaundice, caused by bilirubin levels exceeding 3 mg/dL in the blood. Causes include liver disease (hepatitis, cirrhosis), bile duct obstruction, and blood disorders. Seek medical attention immediately if you notice yellowing of the eyes, especially with abdominal pain, fever, or dark urine. This guide covers the main causes, symptoms, and when to see a doctor.

The Snellen chart is a standardized letter chart used to measure distance visual acuity. Herman Snellen, a Dutch ophthalmologist working at the Netherlands Hospital for…

In most cases, no. Visible scratches on modern eyeglass lenses run through the anti-reflective (AR) coating stack, which cannot be polished out without removing the…

Seven progressive-specific fitting errors that cause patient adaptation failure and remakes, with tolerance thresholds, measurement methods, and pre-dispense fixes.

Blurry vision has five primary causes: refractive errors (myopia, hyperopia, astigmatism), cataracts, glaucoma, diabetic retinopathy, and retinal detachment. Refractive errors account for the majority of…