GA/T 1582-2019Forensic sciences - Technical specifications for examination of visual dysfunction (English PDF)

3.1 Basic principles

Forensic identification of visual dysfunction should use clinical ophthalmology, visual science, and forensic theory and technology, combined with forensic identification practice, Based on objective inspection, comprehensive analysis and comprehensive judgment are made.

For the visual dysfunction after the subject reports self-injury, the appraiser should analyze the visual function according to the inspection results of the eye organ structure.

Impaired pathological basis. For visual dysfunction that cannot be explained by the nature, location, degree, etc. of the injury, the injury and the Cause and effect relationship of visual dysfunction; for visual dysfunction related to own disease and cognitive dysfunction, the relationship of injury and illness should be analyzed.

3.2 Identification steps

3.2.1 Review and appraisal materials

First, you should understand the history of trauma in detail. The materials to be collected mainly include medical history materials, which should be reflected as comprehensively, completely and fully as possible.

a) the time of injury, the injured object and the method of injury;

b) main symptoms and signs after injury;

c) The main diagnosis and treatment after the injury, including the recovery.

If necessary, you should know the history of ophthalmology before injury 1), ask about the history of familial disease, the history of systemic disease and the history of medication.

3.2.2 Visual function test

According to the subject's complaints of visual dysfunction, check their visual functions such as vision and visual field.

3.2.3 Eye Structure Examination

Eye appendix, anterior segment of the eyeball, and posterior segment of the eyeball are performed in order of the right eye first, the left eye later, or the order of the healthy eye and the injured eye.

Check. Among them, slit lamp microscope examination and fundus examination should be performed in a dark room. Choose refraction, intraocular pressure, eye movement, Eye examination, binocular vision, lacrimal apparatus, eye imaging and other targeted examinations.

The inspection results shall be recorded in real time, objectively and comprehensively; the inspection results shall be filmed and archived for review.

3.2.4 Testing for false blindness or camouflage loss

For cases where suspected false blindness or camouflage vision reduction is required, a corresponding false blindness or camouflage vision reduction test can be selected Check, or refer to the results of visual electrophysiology tests.

3.3 Evaluation of results

If it is determined that the injury caused visual impairment, the degree of the impairment should be the same as that of the primary injury or the complications or sequelae caused by the injury.

The nature and degree match.

If it is determined that the impairment caused visual dysfunction, the degree of impairment should be equal to the result of false blindness or camouflage vision reduction test and/or visual electricity generation.

Reasonable test results agree.

If it is determined that the injury caused visual dysfunction, the influence of its own disease or pathological basis should be ruled out.

3.4 Identification timing

The identification of visual dysfunction should in principle be carried out after the injury or the complications caused by the injury and the sequelae have ended.

The above medical termination refers to the stabilization of clinical effect after the implementation of medical measures recognized by general principles of clinical medicine, that is, eye injury Symptoms disappear or stabilize, and eye signs and visual functions tend to be relatively fixed.

Generally speaking, for minor eye injuries that do not leave obvious visual dysfunction, the timing of identification can be appropriately advanced; if there is visual function Impairment or visual impairment as the main basis for the assessment of the degree of impairment and the assessment of the degree of disability, it is recommended that the time of identification is the day of the injury After 90 days.

Including visual functions.

4.1 General inspection of eye structure

4.1.1 Examination of the external eye

Check the orbits, eyelids, conjunctiva, eyeball protrusion, eye position, eyeball movements, lacrimal apparatus, and intraocular pressure.

4.1.2 Anterior segment examination

Use a slit-lamp biological microscope or flashlight to inspect the cornea, sclera, anterior chamber, iris, pupil area, lens, and anterior segment glass Body structure.

4.1.3 Posterior segment inspection

Use direct ophthalmoscope and other equipment to inspect vitreous body and fundus.

In order to expand the scope of fundus examination and improve accuracy, dilated pupil examination is feasible when there are no contraindications.

4.2 Inspection of behavioral vision

4.2.1 Eyesight

4.2.1.1 Preparation

Use of international standard eye chart. Specify the visual mark and ask the examinee to read it. Based on the minimum visual acuity it read out, it determined its visual acuity. Check distance Generally, it is 5m; when the distance of the examination room is less than 5m, the reflection distance of the plane mirror can be used to extend the inspection distance. The chart height should be 1.0 it is advisable to travel at the same height as the eye to be examined. The illumination of the watch should be uniform without glare, and the illumination is 300lux ~ 500lux.

If an eye chart projector is used, the inspection distance can generally be 3m ~ 6m according to the requirements of the instruction manual.

4.2.1.2 Inspection

The routine is to check the right eye first and then the left eye; it is also possible to check the healthy eye first and then the injured eye.

The wearer first measures the vision of the naked eye, then measures the vision of the wearer and records the power of the corrective lens. Cover one eye with a blindfold and check the other with naked eyes vision. From the larger visual target, the direction of the visual target is accurately pointed out within 3s. After the visual mark of the line is correctly identified, the line can be changed downward; if the line More than half of the visual mark cannot be correctly identified and should be line-up.

If the subject is unable to identify the direction of the largest visual target, make him approach the vision chart gradually until the direction of the visual target can be identified. But tested the distance between the user and the target is not less than 1m.

If the direction of the largest visual target cannot be recognized when approaching 1m, check the ability of several fingers instead. Ask the examinee to backlight, the examiner to extend Take a few fingers and tell them to see the index of the hand they see. If the inspected eye cannot recognize the hand index within 1m, the inspector changes his hand to the inspected eye Shake forward and observe if the subject can be identified. If the inspected eye cannot recognize the manual, check whether it has the ability to recognize the light sense in the dark room.

Candlelight or spotlight flashlights project the eye to be inspected and observe whether it can be identified.

If you have light-sense vision, record the nine positions if necessary (front, upper right, right, lower right, upper front, lower front, upper left, (Left, bottom left) light positioning.

4.2.1.3 Record

The visual acuity value represented by the smallest visible target can be recorded as the visual acuity of the eye to be examined.

Example 1. If there are 2 optotypes in the "1.0" optotype row that are not correctly identified, you can record the visual acuity represented by the optotype in the row, and record the incorrect identification in the upper right corner the number of visual targets is represented by a negative sign --1.0-2.

Example 2. If all of the "0.9" visual target lines can be accurately identified, there are 2 individual visual targets in the "1.0" visual target lines, but less than half of them can be recorded.

The visual acuity value represented by the identified visual target line is taken as the visual acuity level of the eye, and the number of visual targets identifiable in a line is recorded in the upper right corner, which is represented by a positive sign-0.9 2.

When checking the digital finger ability, if the subject's eye can only distinguish the hand index 50cm from the subject's eye, it will be recorded as digital finger/50cm (CF/50cm).

When checking the manual recognition ability, if the inspected eye can only recognize the hand shaking 20cm in front of the eye, it is recorded as manual/20cm (HM/20cm).

When checking the light sensing ability, if you can see the light, record it as light perception (LP), if necessary, record the maximum distance that can be recognized, such as 5m Light perception or LP/5m; otherwise recorded as no light perception (NLP).

When checking the light positioning, check front, top right, right, bottom right, top front, bottom front, top left, left, bottom left Fang et al. Have a total of nine positions. "" Indicates that they can be identified, and "-" indicates that they cannot be identified.

4.2.1.4 Vision conversion with changing test distance

It was learned that the subject gradually approached the visual acuity table to see the maximum distance of the visual target, and the visual acuity of the examined eye was converted according to the following formula.

V = (d/D) V0

In the formula.

V-subject's visual acuity;

V0-the level of vision represented by the smallest visual mark;

D-the distance at which the target can be clearly seen by normal eyes;

d-the actual distance at which the subject sees the target.

Example 3. If you see the 0.1 line of sight, the vision is (3/5) × 0.1 = 0.06.

4.2.2 Refraction

4.2.2.1 Preparation

If the vision does not reach the normal level or is lower than the starting point specified by the evaluation standard, it should be checked for refractive abnormalities to determine whether correction is needed.

Vision check.

4.2.2.2 Inspection

The visual acuity of the eye to be examined can be checked with a pinhole mirror. If the visual acuity is significantly improved 2), it may indicate that there may be abnormal refractive errors.

Computer refractometers and/or optometry can also be used to understand the presence and absence of refractive abnormalities and their approximate extent;

Audition to see if you can improve your vision.

4.2.3 Correcting vision

Pinhole mirror vision. If the vision of the eye under test is improved under the pinhole mirror, the pinhole mirror vision can be recorded. If naked eye vision is 0.3, pinhole Vision under the microscope is 0.6, then recorded as. 0.3, pinhole mirror -> 0.6.

Insertion vision. Those who have improved vision after insertion audition can record insert vision. If the naked eye vision is 0.3, when the -2.00Ds ball lens is inserted If it is 0.8, it is recorded as. 0.3, -2.00Ds -> 0.8.

For those who have improved vision after inserting the combined ball lens and lenticular lens, the power of the combined ball lens and lenticular lens and their inserted vision should be recorded. Naked eye vision it is 0.3, when trying to insert -2.00Ds spherical lens combined with -0.75Dc × 90 ° cylindrical lens, the vision is 0.8, which should be recorded as. 0.3, -2.00Ds-0.75Dc × 90 ° -> 0.8.

The best corrected visual acuity should be checked and recorded, including the visual acuity of the pinhole lens and the insertion test.

4.2.4 Evaluation of visual impairment

The specific calculation and evaluation methods are in accordance with the provisions of A.1 in Appendix A.

Increase by 2 lines or more.

4.3 Visual Field Inspection

4.3.1 Contrast visual field examination

It is assumed that the inspector's vision is intact. The examiner sits opposite to the examinee at a distance of 1m. The examiner covers the right eye and the examinee covers the left eye.

Examine his right eye. The subject was instructed to fixate his left eye to the left eye. The examiner reached out and held a white circular sight or finger from the temporal side to the center the field is moved slowly, so that the subject will make a gesture when he sees the marker in the light of his right eye to compare the difference between his visual field and the inspector.

Repeat this action to check the four directions of the upper, lower, and nasal sides or increase the direction of supratemporal, subtemporal, supranasal, and subnasal to eight directions. Check by the same method the subject's left eye. If two people see the visual target or similar at the same time, it indicates that the subject's visual field is generally normal.

This inspection method can only make a preliminary assessment of the visual field of the examined eye, and it is difficult to obtain accurate and quantitative results.

4.3.2 Manual perimeter inspection

Manual perimeter is mainly used to check the peripheral field of view. Generally, first move the visual target from the outside to the inside, and then move from the inside to the outside to compare the two.

As a result, the inspection can be repeated if necessary.

4.3.3 Computer automatic perimeter check

4.3.3.1 General principles and methods

There are many types of computer automatic perimeter, but the principle is the same, and the basic structure is as follows.

a) Fixing device. including the structure for fixing the head and the fixation point for the subject's fixation;

b) Vision standards and mobile devices. Vision standards can have different diameters (1mm, 3mm, 5mm, 10mm), the most commonly used clinically are 3mm and 5mm Optic diameter of the diameter. The 1mm diameter sight is mainly used to check the dark spot in the center. Under certain circumstances, it can also be based on good central vision Bad as a reference for choosing the size of the target;

c) Lighting. The lighting intensity cannot be changed during the inspection, and the conditions cannot be changed when the inspection is repeated;

d) Recording. usually automatic recording.

4.3.3.2 Dynamic visual field inspection

Dynamic visual field inspection is to use the same stimulation intensity cursor to move from an invisible area to the center visible area to explore the invisible area and the visible area Method of dividing points. Dynamic visual field examination can comprehensively measure the visual field range and determine the peripheral visual field, which is of great significance for forensic identification, but when detecting light and dark spots in the field of view, the sensitivity is poor.

5mm diameter optotypes are recommended for forensic evaluation.

4.3.3.3 Static visual field inspection

Visual field defects can be divided into absolute defects and relative defects according to the disappearance and reduction of sensitivity. Static threshold visual field measurement can be performed by the detection of eye sensitivity is used to quantitatively analyze the degree of visual field defect, and is mainly used for the detection of central visual field. Inspection process is automated by computer program control.

Static threshold visual field measurement refers to the use of visual targets with different stimulus intensities in the same position in order to make the subject feel the lowest thorn used.

The intensity of the shock, which is the measured threshold, is often used for the detection of relative visual field defects. This method can reflect the decrease of visual acuity.

The absolute visual field defect was detected by stimulating visual targets above the threshold.

In forensic evaluation, the purpose of visual field inspection is mainly to understand the size of the visual field. Generally, the visual field defect is used to calculate the visual field deficiency.

The basis of the damage range, but the static visual field inspection results have a good correlation with the dynamic visual field inspection, which can be used as a qualitative evaluation and assessment.

An effective method for the reliability of the results of the modal inspection.

4.3.4 Evaluation of visual field defects

4.3.4.1 Factors Affecting the Results of Visual Field Examination

The factors that affect the results of visual field examination are mainly the following aspects.

a) Age. is the main factor affecting psychophysical examination. With increasing age, retinal sensitivity gradually decreases, and the isoline shows Centripetal reduction

b) Pupil size. Generally, when the visual field inspection is performed, the pupil diameter is greater than 3mm. Too small will seriously affect the visual field inspection results, but it is too large.

Will affect the quality of retinal imaging;

c) The degree of light adaptation or dark adaptation of the examined eye. the function of the macula is optimal when the light is adapted;

The macular fovea retina has increased sensitivity to light. When inspecting, the eye to be inspected should be fully adapted to the background illumination of the perimeter;

d) Fixation. During the visual field examination, the quality of fixation has a great influence on the accuracy of the test results. Computer perimeter Attached fixation test procedure;

e) Refractive errors. Uncorrected refractive errors cannot make the cursor focus on the retinal plane, and the test results cannot represent the true vision.

Field, so you should choose appropriate corrective lenses when testing;

f) Learning effect. When the first-time visual field examiner re-examines, the isoline is often slightly larger than the initial result. But as the number of visual field reviews increases Plus, the effect of the learning effect becomes smaller;

g) Human factors. such as the edge of lens frames, corrective lenses, high false positive rate, high false negative rate, etc., full attention should be paid during inspection;

h) Inspection technology. If the inspector's experience, the applied visual target, background lighting, and stimulation time will affect the inspection results.

4.3.4.2 Evaluation of visual field defects

The fields of vision referred to in the forensic evaluation standards are peripheral fields of vision. Therefore, in the practice of identification, the peripheral field of vision should be checked and the corresponding methods should be used.

Method to calculate the degree of visual field defect.

The specific calculation and evaluation methods are in accordance with A.2 of Appendix A.

4.4 Testing for false blindness and camouflage loss

4.4.1 Pseudo-blindness

That is to pretend to be blind.

4.4.2 Binocular pseudo-blind test

4.4.2.1 Behavioral observations

Pseudo-blind people generally do not cooperate with inspections, or refuse inspections. Have the subject look at the target in front of their eyes, and the subject will deliberately go to other parties Look forward. Pseudo-blind people with binocular usually don't stumble when passing obstacles, while those who are truly blind often stumble.

4.4.2.2 Optokinetic nystagmus test

Make the subject look at the visual drum that rotates quickly in front of the eyes, and the screen has vertical lines. The pseudo-blind person can appear horizontal, alternate fast, and have rhythm.

Beating nystagmus, that is, optokinetic nystagmus; true blindness does not occur.

4.4.2.3 Blink test

Use your fingers or cotton swabs to make sudden movements in front of the blind eye when the subject is not paying attention, but do not touch the eyelashes or eyelids.

Then there is no response, and the blind person immediately blinks.

4.4.3 Monocular pseudo-blind test

4.4.3.1 Obstacle Reading

Ask the examinee to read horizontal books and newspapers at a distance of 30cm, so that the head and the reading are fixed. Then place one between the examinee's eyes and the reading.

Vertical pen, about 10cm away from the eye; if you use only one eye, it will inevitably cause dyslexia due to the obstruction of the sight of the pen in front of you Undisturbed reading proves that it is a binocular fixation reading, and this "blind eye" should be pseudo-blind.

4.4.3.2 Pupil examination

The eyes of the pseudo-blind should have equal pupils, but the pupil dilation caused by drugs should be ruled out. Observe pupil reflection on light, pseudo-blind eyes reflect light directly Existence, healthy eyes also indirectly reflect light, but attention should be paid to subsequent damage to the lateral geniculate body. Pupil size, shape, and light reflection may not occur.

Shoot abnormally.

4.4.3.3 Blink test

Cover healthy eyes, use fingers or cotton swabs to make a sudden piercing motion towards the blind eye when the subject is not paying attention, but do not touch the eyelashes or eyelids.

If it is true blindness, there is no response, and the pseudo-blind person immediately appears blinking action.

4.4.3.4 Simultaneous inspection

Contemporaneous perceptual pictures with binocular angles above 10 °. In normal eye position, if you can see both pictures at the same time, it means that both eyes are the same.

The visual function is called pseudo-blindness.

4.4.3.5 Triangular prism test

Including the following.

a) Duane test. Ask the subject to look forward at a target and place a -6 delta triangular prism in front of the so-called blind eye. The bottom of the triangular prism can be turned inward or outward.

Also, pay attention to whether the eyeball is turning; if it is pseudo-blind, the eyeball must be outward when the prism is inward, and the eyeball must be when the prism is outward.

Move inward to avoid double vision;

b) Cover the so-called blind eye, and place a 6 delta bottom triangular prism in front of the healthy eye so that its edge is exactly in the center of the pupil.

Give a single eye diplopia, then remove the cover in fr...