Diagnosis of foreign bodies in the eye

To detect fragments, the following conditions are necessary: transparency in front of the lying medium; Detection of fragments in a zone accessible for clinical examination. If a significant damage to the eyeball does not occur during the introduction to the eye of the foreign body and gaping wounds are not formed, then the X-ray method of Comberg-Baltic is used to determine the localization of the intraocular foreign body. Use a prosthetic indicator. It is an aluminum ring, in the center of which there are holes for the cornea 11 mm in diameter. The set has three prostheses. They are selected for patients taking into account the radius of curvature of the sclera Four lead labels are soldered along the edge of the prosthetic aperture. After local anesthesia, an indicator prosthesis is superimposed over the eye, so that its labels are located on the limb, respectively, 3, 6, 9 and 12-hour meridians. They make two X-ray images - in a straight line and lateral projections. Then, the measuring circuits are applied to the pictures and determine which meridian the foreign body is at, at what distance from the sagittal axis and from the plane of the limb. This is the most common method for detecting foreign bodies, but it does not always help to establish the presence of a foreign body or to determine precisely whether it is located in the eye or outside the eye.

To determine the location of foreign bodies in the anterior part of the eyeball, the method of non-skeletal X-ray radiography according to Vogt is used no earlier than 7-100 hours after injury. In clinical practice, other methods are used to detect foreign bodies in the eye. Information on the location of the fragment and its relationship with the membranes of the eye are obtained with the help of an ultrasound diagnostic method when using B-scan. In computationally difficult cases, a CT scan is performed. In those cases when, by means of usually radiography, it is not possible to detect a foreign body inside the eye, and clinical data indicate its presence, it is advisable to apply radiography with a direct magnification of the image. This method allows you to identify the smallest foreign bodies (not less than 0.3 mm), located not only in the foreleg, in the back of the eyeball. In addition, using radiography with a direct magnification of the image, it is possible to detect low-contrast foreign bodies that are poorly or not at all visible on conventional radiographs.

When examining patients with extensive damage to the eyeball and loss of intraocular membranes, as well as children of younger age, when contact methods for determining the localization of intraocular foreign bodies are contraindicated or difficult to implement, a non-contact method should be used.

In the examination of patients with multiple foreign bodies, the stereo-X-ray method of their localization provides invaluable assistance. This method is expedient to apply also in the presence of non-fixed fragments located in the vitreous body in patients, since in such cases the position of the patient during X-ray examination and on the operating table is the same. With these methods, a fragment in the eye can be detected in 92% of all patients. Only the smallest fragments of glass, localized in the anterior segment of the eye or practically destroyed by prolonged exposure, and also foreign bodies located in the posterior part of the eye (8% of cases) remain unidentified. Computerized axial tomography is used to detect intraocular foreign bodies. Advantages of the method are the speed and painlessness of the study, as well as obtaining accurate information on the relationship between the foreign body and intraocular structures. It is particularly advisable to apply the method for multiple foreign bodies. The minimum size of a fragment of a metal detected by tomography is 0.2 × 0.3 mm; glass - 0,5 mm.

At present, electronic locator devices are widely used for diagnostics, with the help of which localization of metallic foreign bodies and their magnetic properties are determined. The method of examining patients using any locator is as follows. First determine the foreign body in the eye, bringing the sensor to different parts of the eyeball; while fixing the deviations of the arrow from the middle of the scale and the sign of this deviation. In the case of detection of a foreign body in the eye, localization is determined by the described method by the maximum deviation of the indicator needle from the origin; the place in the eye to which the sensor was brought at the time of maximum deviation corresponds to the closest location of the intraocular foreign body in relation to the shells of the eyeball. In the event that the deviation of the arrow of the indicator is small, increase the sensitivity of the device.

The device can be used in polyclinic conditions to quickly determine the metal fragment in the eye and its approximate localization. The device can also be used during removal of the foreign body from the eye to clarify the localization.

One of the valuable methods of diagnosing foreign bodies in the eye is ultrasound. Ultrasound in the treatment of injuries with the introduction of foreign bodies used to determine the location of foreign bodies and, more importantly, to obtain an accurate characterization of traumatic eye injuries.

At present, for the ultrasound diagnosis of foreign bodies, the eye is used both as a one-dimensional echography and as a scanning echography. By the form of the echogram, it is possible to determine the nature of the pathological changes, and also to differentiate each of them, in particular, to ascertain the presence of a foreign body. Ultrasound examination is performed with the help of the domestic ultrasound diagnostic device "Echoophthalmograph". This method is effective only in conjunction with radiography and in no case can be used as an independent method of diagnosis.

After the presence of a foreign body in the eye is established, it is important to clarify its nature: it is a magnetic or amagnetic fragment. For this, there are a number of samples: the echographic localization of the fragments is performed with the help of an ultrasonic device called "Eco-phthalmograph", the locators described above are used to determine the magnetic properties of the fragment. They also include a metalphone created by PN Pivovarov. When you approach the metalophile probe to the metallic foreign body, the tone changes in the headphones of the phone - "sound splash". Magnetic fragments give a higher tone than the core. Foreign bodies with a diameter of less than 2 mm are difficult to distinguish by sound, so the device can be used mainly for detecting a fragment in the eye and determining its localization.

To detect very small fragments of iron or steel, the method of sideroscopy is used. In the most difficult cases, the chemical examination of the anterior chamber helps to determine the presence of a foreign body and to clarify its nature. Such an investigation is carried out in extreme cases, when all other methods do not have an effect. A chemical study of the moisture of the anterior chamber on iron makes it possible to detect early signs of siderosis or chalcosis. However, the sample may be negative if the foreign body is surrounded by a connecting capsule.

In recent years, fundamentally new methods for diagnosing foreign bodies have been developed. Describe the technique of television ophthalmoscopy in light, as well as the color cinematography of the fundus used to determine the location of fragments in the retina. Using special filters, you can determine the presence of the intraocular body with opacity of the cornea and the lens. The phenomena of retinal siderosis can be detected using fluorescent angiography of the retina and optic nerve.

Diagnosis of foreign bodies is carried out with the help of an electromagnetic sensor. The method allows to determine the depth of the foreign body, its size and the type of metal.

All the above methods of diagnosis of foreign bodies can determine whether there is a fragment in the eye, as well as its magnetic properties. In the future, when extracting a fragment, it is extremely important to determine its projection on the sclera.

[1], [2], [3], [4], [5], [6]

Methods for refining the projection of a foreign body onto the sclera

The tactics of surgical intervention depend to a large extent on the location and size of the fragment, as well as the time that has passed since the injury of the eye. In order for the dyskleral operation to be successful, it is necessary to determine the exact location of the foreign body and to make an incision in the scleral site closest to the fragment, almost above it.

There are several ways of transferring the projection and the rock body to the sclera, special calculations and tables are proposed for determining the projection site of the ophthalmoscopic ophthalmoscopes on the sclera and pathological foci. Currently, the standard radiographic methods for determining the localization of intraocular fragments allow us to determine the following parameters:

1. the meridian of occurrence of fragments;
2. distance from the anatomical axis of the eye;
3. The depth of the fragmentation along a straight line from the plane of the limb.

The first two parameters without corrections are used for the deasclerial removal of the fragment.

Method of transillumination using a diaphanoscope, which is attached to the cornea. In this case, clear scleral translucence is clearly visible, against which a dark spot of the foreign body stands out. This method is very valuable when removing both magnetic and non-magnetic foreign bodies located near the wall and in the membranes of the anterior and posterior parts of the eye.

Thus, the following scheme for determining the location of a foreign body on the sclera is proposed.

Clinical definition of the location of a foreign body

1. X-ray diagnostics of the fragment and determination of the size of the eyeball (X-ray and ultrasound methods).
2. Refinement of the projection of the foreign body on the sclera according to the table, taking into account the size of the eyeball.
3. Use of the parameter method in transparent media to clarify the location of a foreign body.
4. A mark on the sclera in the proposed location of the foreign body, depending on the state of the eye, which is produced as follows:
   • in transparent media after preliminary ophthalmoscopy, coagulate is applied by the apparatus for diathermocoagulation, then a repeated ophthalmoscopic examination is performed (determine the mutual position of the coagulum and foreign body), localization is clarified by the method of transillumination;
   • with cataracts or turbidity of the vitreous body using transyaluminatsiyu using a diaphanoscope, which with a certain accuracy allows you to project a foreign body on the sclera;
   • when the fragment is localized far beyond the equator, in the posterior from the eyeball, retrobulbar diaphanoscopy is used;
   • with hemophthalmia, and also in the case of the foreign body's location in the ciliary body, transillumination can be used using a diaphanoscope with lightguide, electron location, ultrasound diagnostics or labeling. However, the latter method can be recommended in the most extreme cases. This method can be used in hemophthalmia, when the transillumination and retrobulbar diaphanoscons do not give an effect.

The use of all these methods to refine the projection on the sclera of magnetic and amorphous foreign bodies located near the wall or in the shells of the eyeballs ensures the efficiency of the debris removal operation.

[7], [8], [9],