Methods and devices for the measurement of the degradation of image quality on the retina of the human eye due to cataract

摘要

Cataract and other diseases of the eye which degrade the clarity of the ocular media cause blurred vision and sensitivity to glare. Vision tests that require patients with unclear ocular media to read letter charts are not always reliable indicators of vision loss because these tests are sensitive to such subjective variables as patients' reading and language skills as well as neurological status. The invention provides a non-invasive means for the objective assessment of vision loss in patients with unclear ocular media thus overcoming the difficulties associated with subjective vision tests. The methods and devices of the invention provide the means for: 1) projecting the image of an external target source onto the patient's retina, 2) forming a second image of the retinal image of the target source onto the recording plane of an electronic camera, 3) transferring the electronic image to an image processing computer, and 4) measuring the extent of blurring of the retinal image of the target source with the computer. Vision loss is associated with the magnitude of the measured extent of the blurred retinal image.