Intraocular foreign body

Introduction to foreign bodies in the eye Intraocular foreign bodies (intraocularforeignbodies) are a special kind of eye trauma, which is more harmful than general eyeball perforation. The foreign matter enters the eyeball, and in addition to the mechanical damage caused by the injury, the damage to the eyeball is increased due to the retention of the foreign matter. In general, intraocular foreign bodies require early diagnosis and timely surgery to protect the eyeball and preserve vision. Types of foreign bodies in the eye: Intraocular foreign bodies are classified into two categories: magnetic and non-magnetic. Magnetics can be sucked out by magnets during surgery; non-magnetic foreign bodies include other metals, alloys and non-metals. The extraction of non-magnetic foreign bodies is mostly difficult. The position of foreign bodies in the eyeball is about 20% in the anterior segment of the eyeball, and about 80% in the posterior segment of the eyeball, of which 10% is located in the eye wall. The left eye is more than the right eye, and both eyes have a foreign body retention of about 1%. basic knowledge The proportion of illness: 3% Susceptible people: no special people Mode of infection: non-infectious Complications: iridocyclitis retinal detachment

Intraocular foreign body cause

Cause (65%):

The vast majority are steel magnetic foreign bodies. Foreign bodies damage the tissues in the eye, which can cause pathological and functional changes in the tissues.

Intraocular foreign body prevention

Intraocular foreign bodies, regardless of their nature, may bring bacteria into the eye, and the contents of the eye are places where bacteria can easily multiply. Once suspected foreign bodies in the eye, anti-infective treatment should be strengthened immediately to prevent the occurrence of suppurative endophthalmitis. Quickly make a diagnosis and localization of the foreign body in the eye, remove the foreign body in the eye and suture the wound as soon as possible, and check it regularly after surgery, especially in the two weeks after the injury, pay attention to the occurrence of sympathetic ophthalmia.

Intraocular foreign body complications Complications, iridocyclitis, retinal detachment

The discovery of intraocular foreign body complications: foreign bodies in the eye persist for a long time, and some complications often occur. At this time, the diagnosis can be made according to the complications, and then confirmed by other methods. The common complications are as follows:

1, eye rust (siderous bulbi)

The iron foreign matter remains for several days to several months, and rust can occur. It first appears around the foreign body, and then spreads and spreads to the tissues in the eyeball, showing a brownish yellow fine-grained sediment, and the cornea is mostly in the stromal layer. There are many parts, the iris is brown, and the iris is atrophied for a long time. After the adhesion, the pupil is moderately scattered, and the light response is weakened or disappeared. The crystal first appears brown under the anterior capsule or forms a round, oval spot, and then the cortex. It is turbid and diffuse brownish yellow. The vitreous turbidity of the vitreous is tan. The retina is easily invaded and degenerated, which is characterized by vision loss and visual field reduction.

2, ocular chalcosis (ocular chalcosis)

When copper abnormally enters the eye for several hours, the increase of copper content can be found in the aqueous humor. However, the clinical appearance of copper rust is often several months or more after the injury. The higher the copper content of the foreign matter, the heavier the copper rust. , containing more than 85% of copper, the damage is serious, pure copper can cause acute aseptic purulent, when the foreign body is wrapped by mechanical tissue, the copper rust is relatively light, the small copper foreign body expressed by the iris often does not occur copper rust, cornea The copper rust is most obvious in the posterior elastic layer of the peripheral part, and the typical performance of the Keyser-Fleischer ring is often presented clinically.

3, iridocyclitis

Long-term reactions of unexplained monocular iridocyclitis or total uveitis should be asked in detail about the history of trauma and other tests to confirm or rule out the presence of foreign bodies in the eye.

4, cataract

Young adults with unexplained cataracts can sometimes be caused by foreign bodies in the crystal or foreign matter passing through the crystal.

5, other complications

Unexplained vitreous opacity with organic membrane or cord, secondary retinal detachment with one eye, secondary glaucoma with unexplained single eye, etc., should also consider the possibility of foreign body retention in the eye, and carry out corresponding examination.

Intraocular foreign body symptoms Common symptoms Increased eyesight Eye pain Visual impairment Eyelid foreign body eye piercing

Visual impairment, eye pain can occur.

Intraocular foreign body inspection

There are several methods for localization of intraocular foreign bodies:

1, ophthalmoscopic localization (ophthalmoscopic localization)

(1) Contrast positioning method: Under the ophthalmoscope, the diameter of the optic papilla (average 1.5mm) is used as the measurement scale, and the diameter of the nipple from the fovea of the macula is measured, and the foreign matter in the peripheral part is measured, and the distance from the serrated edge is measured. Then, determine the warp where the foreign object is located, expressed in the direction of the clock, and the foreign matter in the peripheral part must be positioned with an indirect ophthalmoscope or a slit lamp.

(2) Perimeter positioning method: With the hand-held small field of view, the warp and weft of the foreign object are measured by direct ophthalmoscope, and then the position is calculated. The longitude does not need special calculation, and only the warp where the foreign object is found is changed. It can be in the direction of the clock. The relationship between the warp and the clock direction (the same as the left and right eyes) is: starting from 3 o'clock, rotating in the counterclockwise direction, that is, 3 o'clock is 0 o; 12 o'clock is 90 o; 9 o'clock is 180 o; 6 o'clock is 720 o.

(3) Positioning of floating foreign objects

1 Measure the distance between the foreign body and the wall of the eyeball: Indirect ophthalmoscope can use stereoscopic view to determine the distance between the foreign body and the wall of the eyeball. The direct ophthalmoscope can be used to measure the distance of the millimeter of the distance by separately observing the retina and foreign matter near the foreign object. For the surface, the lowest concave mirror or the highest convex lens can be used. The difference between the lens powers used to see the two is calculated, and the distance between them can be calculated according to the difference of 3 mm per 3D.

2 Understand the extent of foreign body activity: After seeing foreign objects, let the eyeball turn to one side, then quickly return to the original position to observe the range of foreign body activity.

3 Understand the position of the foreign body closest to the eye wall: take the sitting position, supine position, left lateral position, right lateral position, prone position, head low position, combined with the upper, lower, left and right rotation of the eyeball, press The aforementioned measuring distance method measures the distance between the foreign body and the eye wall, compares the position of the foreign object in each body position, and finds the farthest distance from the eye wall and the nearest body position.

(4) Magnetic test: Any foreign object that can be seen with the diameter of the ophthalmoscope can be magnetically tested to understand whether the foreign matter is magnetic or magnetic, and to understand whether the foreign matter is fixed or fixed. When testing, first check the foreign matter to The tip of the head of the hand-held electromagnet points to the foreign object, starting from the distance of 10cm from the eye, and switching from far to near to observe the synchronous movement of the foreign object with the switch of the electromagnet. The head contacts the eyeball, the foreign object is still not moving, and the visibility is negative. At this time, a large electromagnet can be used for the test. The negative result indicates that the foreign matter is non-magnetic or magnetic, but is firmly fixed on the wall of the eyeball, and is difficult to be removed. Generally, the non-magnetic foreign matter extraction method is required for the operation.

2, X-ray localization (X-ray localization)

The X-ray localization method is a method for the localization of foreign bodies in the eye. The positioning result is accurate and reliable, and is not affected by the turbidity of the refractive medium of the eye. It is the most commonly used method in clinical practice.

(1) Direct positioning method: the method of directly measuring the position of a foreign object from the X-ray positive position and the lateral position sheet, the specific method is:

Limbal marking: the most simple way to place a metal mark on the limbus is to sew a metal ring around the limbus, but preferably a locator with a pointing rod, which is a plastic angled contact lens. It has a metal ring with an inner diameter of 11mm at the edge of the limbus; a metal indicator rod with a length of 20mm and a diameter of 2mm is located in the middle of the front of the limbus, and the fixed device is fixed on the surface of the eyeball by suturing or adsorption.

The method of taking the positive position film: the patient is lying prone, the head is slightly up, so that the hearing line and the inspection table (or the film) are at a 45o angle, the eyeball is looking down, and the tube is vertically projected from the top to the X-ray center. The line is consistent with the sagittal axis of the eyeball, and the height of the tube is adjusted so that the ratio of the target to the eye is 10:1. According to the condition of the head position, the film is larger than the actual object, and the ratio of the two is 1.1:1. .

The method of taking the lateral position: the patient is lying on the side, the head is placed on the side, the affected side is close to the table (or the cymbal), the sagittal surface of the skull is parallel to the table, the eyes are gazing horizontally, and the tube is draped from above. The center line of the X-ray is consistent with the corneal plane, and the ratio of the distance between the target and the distance of the eye is 10:1. According to the condition of the lateral position of the skull, the ratio of the photographed to the actual object is 1.1:1.

The method of reading the film: the distance between the warp and the foreign matter in the sagittal axis of the foreign object can be measured on the positive slice, and the vertical distance between the foreign body and the plane of the limbus can be measured on the lateral slice, and the positive and lateral slices can be measured. The measurement is made with an intraocular foreign matter measuring device, which is also drawn at 1.1:1, so it is not necessary to convert the magnification when measuring.

Recording method: After measuring the above three data, it can be plotted on the intraocular foreign body localization record map, and the spatial position of the foreign matter in the eyeball and the relationship between the foreign matter and the eye wall can be seen at a glance.

Correction method: The deflection of the eyeball may occur during filming. Especially when the positive position film is taken, the eyeball skew can form the error of the foreign matter warp and the distance between the foreign body and the sagittal axis. To correct this error, there are two simple methods. It can be used, and it can also be calculated by computer when there are conditions.

1 vertical position correction method: In addition to taking the positive position film, take a vertical position film, the method is similar to the positive position film, let the patient prone, the head volume is back, the hearing line and the table are 30o angle, the eye is positive In the front view, the tube is vertically projected from the top to the bottom. The center line is consistent with the corneal edge plane. The ratio of the target distance to the eye is 10:1. If there is difficulty, it can be 5:1 or 4: 1 Arrangement, the measurement can be carried out with the solid scale in the middle of the intraocular foreign object locator, and the foreign matter is measured at the nasal or temporal side of the sagittal plane for several millimeters, and the foreign matter measured from the original positioning tablet is at the eye level. A few millimeters above or below the cut surface, and then corrected by calculation or mapping method, or corrected by using the intraocular foreign body localization record.

2 indicator rod correction method: if the eyeball is skewed when the positive position piece is taken, the projection of the indicator rod must not be a circle and is an ellipse or a long shape, then the length of the indicator rod is projected to extend the length (L) and the lateral position. The distance between the foreign object on the patch and the sagittal axis (P), calculate the distance to be corrected (d), and calculate the formula as follows: d=L·P/20, after calculating d, the center of the self-aligning ring is extended to the projection of the indicator The distance of the opposite side moving d, that is, the new center, is measured at the origin of the center as the coordinate, and the distance between the measured foreign matter warp and the foreign matter and the sagittal axis is the correct distance after correction.

3 computer positioning correction calculation method: using the computer program calculation, only need to measure the required data on the skewed photos, after inputting into the computer, the position of the warp of the foreign object is printed, the foreign body and the plane of the limbus Distance, the distance between the foreign body and the sagittal axis, the distance between the foreign body and the outer surface of the eyeball, and the optimal incision position. If the length of the eye axis is measured by B/A ultrasound, the dynamic model of the eyeball can be drawn, and the foreign body can be drawn. Plotted on the eyeball map.

(2) Geometric positioning method

The first piece: Like the lateral position piece of the direct positioning method, the contact lens type positioner with the indicator rod is still placed, but the eye is as close as possible to the piece of the eye (the distance of the eye is only about 4 cm), although the tube is raised, The distance between the target and the eye is 100cm; the second piece: quick change (or double exposure without changing the face), keeping the patient's head and eyes completely motionless, moving the tube to the patient's foot, moving the distance to half of the target's eye distance , that is, 50cm, tilt the tube, mark the eyeball (the angle of the tube should be 26o34 ), take the second side.

Measurement and calculation method: draw an extension line of the indicator rod on each of the two lateral slices, that is, the horizontal plane of the eyeball, and measure the horizontal and horizontal offset of the foreign object, and the amount measured by the first piece is ±a. The amount measured by the second piece is ±a , which is + for the foreign matter at the level, and - for the horizontal plane, and is substituted into the formula:

b = [(±a ) - (±a ±)] × 2 (Note) *.

Diagnosis of intraocular foreign body

diagnosis

Diagnosis can be made based on medical history, clinical manifestations, and examination.

Differential diagnosis

Distinguish from the eye-through injury, the eyeball penetrating injury is the first thing that causes the eyeball to penetrate through the eyeball. Therefore, the eyeball penetrating injury is an important basis and a must-have for the diagnosis of foreign body in the eye.

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