Refractive Errors
The refractive error where distant objects appear clear, but near ones are blurry.
What is hyperopia?
Type of lens that converges light rays.
What is a convex lens?
The first step in subjective refraction.
What is retinoscopy?
Type of lens that corrects astigmatism.
What is a toric lens?
Standard chart used for measuring distance visual acuity.
What is the Snellen chart?
A condition where parallel light rays focus in front of the retina.
What is myopia?
Type of lens used to correct myopia.
What is a concave lens?
Test used to determine astigmatism axis and power.
What is the Jackson Cross Cylinder?
These lenses allow for both distance and near vision correction.
What are bifocals?
A term for an eye that has no refractive error.
What is emmetropia?
This condition results from an irregular curvature of the cornea or lens.
What is astigmatism?
Unit of measurement for lens power.
What is a diopter?
Device that contains multiple lenses for refraction testing.
What is a phoropter?
This type of lens design provides a gradual change in power from distance to near.
What is a progressive lens?
What are the two methods of refractometry?
What is subjective and objective?
This term refers to unequal refractive power in the two eyes.
What is anisometropia?
Bending of light as it passes from one medium to another.
What is refraction?
Objective refraction technique using a handheld light.
What is retinoscopy?
Surgical procedure that corrects refractive errors using a laser.
What is LASIK?
This type of chart is used for illiterate or young patients.
What is the tumbling E chart?
The age-related loss of near focusing ability.
What is presbyopia?
Substances that completely block light.
What is opaque?
The condition in which light focuses perfectly on the retina with no refractive error.
What is emmetropia?
Material known for impact resistance in eyeglass lenses.
What is polycarbonate?
This term describes any deviation from emmetropia.
What is ametropia?