The ability of the eye to increase the optical power of the crystalline lens, allowing adjustment of focus for near objects and self-correction of hyperopic refractive errors.
Refraction techniques that suppress accommodation and allow determination of the refractive state with accommodation relaxed.
Symptoms due to persistent or excessive accommodative effort.
Asking a patient to perform a 2-alternative forced-choice comparison of the clarity of vision with alternative lens choices; for example, “Which is better, ‘1’ or ‘2’?”.
Verification that a clinical refraction equally relaxes the accommodation of the 2 eyes.
The process of measuring the refractive status of the eyes of a patient.
The use of plus lens power to blur the vision in 1 or both eyes, encouraging relaxation of accommodation; a method of accommodative control.
Jackson cross cylinder
A lens with cylinders of equal and opposite power, with axes perpendicular to each other, useful for determination of optimal correcting cylinder axis and power.
The measurement of refractive errors through patients’ subjective descriptions of how well they can see.
Phoropter (generic: refractor)
An instrument containing geared spherical and cylindrical lenses for each eye to facilitate subjective refraction.
Pinhole (or pinhole occluder)
A device with a small aperture, or an array of small apertures, allowing a patient to reduce the effective aperture of the eye. If pinhole viewing clarifies a patient’s vision, this suggests the presence of an uncorrected refractive error.