COA Flashcards - Refractometry 6% of exam
What is the name of the instrument that houses various lenses to determine the refractive error of an eye?
Phoropter
Define refractometry
The measurement of the refractive error of an eye.
What is an important factor when preparing a patient for refraction?
The refractionist must explain to the patient to choose the lens that provides the clearest vision
What is a common mistake made by the refractionist?
Moving or flipping the lenses too quickly for the patient.
What are three appropriate starting points for refracting a patient?
Retinoscopy, autorefractometry, or patient’s current spectacle Rx
In what order should refinement of a refraction be performed?
Sphere, axis, then power of cylinder
What accessory phoropter lens is utilized to refine cylinder axis and power?
Jackson Cross Cylinder
Name the two methods of refractometry?
Objective and subjective
In refractometry, the _____ method requires the patient to give answers to the examiner.
Subjective
When is the spherical equivalent best used in a spectacle Rx?
If a patient is an adult who has never worn glasses and requires a large astigmatic correction
What is the name of the test to determine the correct myopic correction using red/green filter on the projector?
Duochrome test
What is another reference or starting point for refractiving a patient who has a poor retinoscopy reflex?
Keratometry
What normally determines the strength of an add power for near correction?
The age of the patient
What type of refractometry is indicated for children with accomodative esotropia or patients who have latent hyperopia?
Cycloplegic refractometry is best used in these situations
What is the distance from the back surface of a lens to the front of the eye called?
Vertex distance
