Apparatus and method for determining subjective responses using objective characterization of vision based on wavefront sensing

Abstract

An apparatus for determining the refraction of a patient's eye includes a wavefront measurement device that determines aberrations in a return beam from the patient's eye viewing a target through a corrective test lens in the apparatus. The wavefront measurement device preferably outputs an display representative of the quality of vision afforded the patient through the test lens. The display may be, e.g., a representation of a Snellen chart convolved with the optical characteristics of the patient's vision, an overall quality of vision scale, or the optical contrast function, all of which are based on the wavefront measurements of the patient's eye. The examiner may use the display information to conduct a refraction examination or other vision tests without the subjective response from the patient.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates generally to methods and apparatus for determining a person's visual characteristics, and more particularly to apparatus and methods for determining the refraction of the eye. [0003] 2. Description of the Related Art [0004] Phoropters are apparatus used by optometrists to determine a patient's visual characteristics, so that proper eye diagnoses can be made and eyewear can be prescribed. In conventional phoropters, a patient looks through the phoropter, in which various test lenses are disposed, at a target eye chart, referred to as a “Snellen chart,” while an optometrist moves the test corrective lenses into the patient's field of view. In some applications, the target may be positioned at a predetermined distance from the patient. The patient is then asked to verbally compare the quality of the perceived image as afforded by one lens versus the prior lens presented. The optometrist ta...

AI Technical Summary

Benefits of technology

[0032] In yet another aspect, a device for aiding a practitioner in knowing the integrated effect of a patient's eye and a test lens placed in front of the eye includes means for sensing an

Problems solved by technology

Unfortunately, as recognized herein, the patient can become fatigued during the process and / or misjudge the vision afforded by the various lenses.

This can lead to the selection of a less than optimum prescription.

Moreover, some patients, such as a very ill or a very young patient, might not be capable of articulating the quality of vision the various lenses afford the patient.

Objective methods of determining the patient's refraction errors have been proposed, but these other methods introduce further complications that are not present when using phoropters.

However, the method does not provide sufficient accuracy for prescribing spectacle lenses.

Unfortunately, the measurement outcome often differs from the patient's ideal prescription.

Moreover, both retinoscopy and autorefraction fail to account for the accommodation effect of the patient, that is, for the propensity of a patient to alter his or her focus or sight to make the best of the vision test.

Examination results that include patient accommodation effects are inaccurate for prescribing spectacle lenses.

Another limitation of the autorefractor is that the examiner has no control over which lens is to be used in the test.

The result is that repeated measurements are likely to provide different results for the same eye from the same patient, which results in laborious and time consuming tests and retests when using the device to finalize a prescription.

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