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The Characteristics Of Optometry Instrument

Optometry apparatus is an essential machine for every ophthalmic hospital and optician shop.

Principle and precautions of optometry instrument

Optometry Instrument is an objective optometry equipment, which is the product of the combination of refractive inspection technology and computer technology. Measurement without the subjective judgment of clinicians and subjects, the objective evaluation of refractive parameters by predetermined criteria. Because the computer optometry is simple, fast, and the learning cycle is short, Optometry Instruments it is suitable for quick access to objective diopter and as a starting point for primary optometry or for routine eye care screening. With the application of high technology in optometry instrument, the accuracy of optometry instrument has been improved greatly, many instruments integrate the function of the corneal curvature meter or the corneal topographic map, and the instruments of some manufacturers are automatically online with the integrated optometry instrument, Optometry Instruments and the measurement results are directly imported into the comprehensive optometry instrument, which is convenient to use.

The principle of optometry instrument the design principle of most optometry instrument is based on indirect fundus mirror, using two objective lens or focusing mirror and a splitter, the light source is directly entered by the pupil edge, the detection cursor can move along the axis of the projection system, Optometry Instruments the projection lens in the front focal plane, the image will be at infinity, then focus on the retina of the eye squarely; if the eye is not refractive, the detection cursor moves back and forth, making it like focusing on the retina, Most optometry instruments are used to automatically calculate the diopter of the eye by changing the degree of light that enters the eye to make the cursor clearly imaged on the retina.

The design of modern optometry instruments usually has two main features:

1. Regulation control is especially important for most optometry methods. Optometry Instruments Almost all optometry requires the person to gaze at the test cursor or cursor image, which stimulates the adjustment and makes the test result myopic or hyperopia, although the test cursor is designed at infinity by the light path,

Because the instrument is very close to the face of the person induced near-perceptual regulation, so in the design process, the test cursor "fog visualization", before the beginning of the measurement, the subject saw a "fog" cursor to relax the adjustment, but can not completely remove the near-perceptual regulation.

2. Detection of light for infrared light is currently used by the optometry instrument detection of light using wavelength of 800~ $number nm infrared light. The reason is: ① infrared is absorbed in the eye less than visible light, reflected by the fundus more light. Therefore, it is more important to detect the light energy loss after the light has passed through the intraocular medium, Optometry Instruments especially the eyes with cloudy refractive media. ② for the eyes, the detection of visual standard and detection of light is not visible, better to overcome the measurement of the problem caused by the visual standard. Due to the different production companies, the design and structure of optometry instruments are also different, and the inspectors need to read the instructions in detail before using optometry instruments. The common structure of optometry instrument is: ① the cursor that the inspector stares at. ② can adjust the jaw and head to make the patient's head position fixed during the examination. ③ joystick can be moved back and forth, up and down, Optometry Instruments to focus and adjust the position of the eye of the seized person. The ④ monitor displays the location and measurement results of the inspected eye. ⑤ printing device.

II. Steps of Computer Optometry

1. Prepare (1) disinfection of jaw and head.

(2) To instruct the seized person to remove his spectacles or contact lenses.

(3) Turn on the power switch.

(4) Initialization of the parameters of the instrument, the parameters set include the symbol of the mirror, vertex distance, contact lens, monitor display parameters, subjective or objective mode, the choice of gaze target, printing mode and display operation mode.

(5) Adjust the height of the chair and the height of the instrument so as to make the position of the inspected person and the Inspector comfortable.

(6) Release the lock switch.

(7) Instruct the person to put the chin into the jaw, and the forehead to rely on the head;

(8) Ascending and descending jaw, until the angle of the external canthus and the height sign on the bracket are aligned.

2. Inspection steps

(1) Select the item of measurement, usually including diopter, corneal curvature. Optometry Instruments It should be noted that different manufacturers and different types of instrumentation may be different functions.

(2) Instruct the seized person to face the cursor in the eye of the optometry system.

(3) through the instrument monitor to observe the right eye position, and use the joystick before and after focusing to make the image clear; Move the joystick up and down so that the cornea Reflex Point cursor is located in the pupil center.

(4) Measure diopter or corneal curvature according to the buttons above the joystick. If automatic mode is selected, the instrument is automatically measured three times after focusing and centering.

(5) Repeated measurement more than three times.

(6) Repeat steps (3) ~ (5) to measure the diopter of the left eye or the curvature of the cornea.

(7) If the corneal diameter is measured and the step (3) is completed, the corneal nose and temporal border are selected through the control button. Measure the diameter of the cornea by pressing the button above the joystick.

(8) Print or record the results of the measurements; Usually the instrument automatically selects two times the nearest and most reliable value as the final result.