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The Design Principle Of Optometry Instrument

Reflective instrument is an electronic objective optometry equipment, is the combination of refractive technology and electronic computer technology products. There is no need for the subjective judgment of the clinician and the subject, and the refractive parameters are evaluated objectively by the pre-set criteria. As the computer optometry simple, fast, short learning cycle, suitable for rapid access to objective diopter and as the main inspiration of the starting point or for daily eye care screening. With the application of high-tech optometry equipment, Optometry Instruments the accuracy of optometry equipment has been greatly improved, many instruments integrate corneal curvature or corneal topography function, and some manufacturers of instruments and integrated refractometer automatically online, The results directly into the integrated refractometer, easy to use; portable optometry equipment can also be used in the surgical process and screening.

First, the principle of computer optometry

Most optometry instruments are based on the principle of indirect ophthalmic lens, the use of two objective lens or focusing mirror and a beam splitter, the light source directly from the pupil edge into the detection of the cursor can move along the projection system, Optometry Instruments located in the front focal plane projection Lens, the image will be at infinity, then in the eyes of the retina on the clear focus; if the eye is eye refractive error, Optometry Instruments detection of the cursor before and after the move, making it focused on the retina, most of the optometry instrument is to change The light spreads into the eye to make the cursor clearly imaged on the retina and automatically calculate the eye's refraction.

Optometry instrument design usually has two main features:

1. Adjust control

For most optometry methods, regulatory control is particularly important. Almost all of the refractors require the subject to watch the test cursor or cursor image, the results stimulate the adjustment and make the results of myopia correction or hyperopia correction, although the test cursor through the optical design at infinity, because the instrument is very close to being seized Of the face, it induced the near-perceived regulation, Optometry Instruments so in the design process, the test cursor "fog visual", before the start of the test, the seizure first saw a "fog" cursor, Optometry Instruments in order to relax But can not completely remove the near-perceived regulation.

2. Detect light as infrared light

At present the use of optometry instruments are used to detect light wavelength of 800 ~ 950 nm infrared light. The reasons are: ① infrared absorption by the intraocular tissue is less visible light, the reflection of the light through the fundus more. Therefore, Optometry Instruments the detection of light through the intraocular vector after the loss of light energy less, especially the measurement of refractive media opacity of the eyes is more important. ② for the eye, the detection of visual and detection of light is not visible, better overcome the measurement caused by the adjustment of the problem.

Due to the different production companies, Optometry Instruments optometry instrument design and structure are also different, the inspectors in the use of optometry equipment before the need to read the instructions in detail. The common structure of the optometry instrument is: ① the cursors watched by the examiner. ② can adjust the jaw and head by, so that the patient's head during the inspection fixed. ③ joystick can be before and after, up and down, left and right movement to adjust and adjust the location of the subject's eyes. ④ monitor shows the location of the eye and the measurement results. ⑤ printing device.