Ophthalmoplegia

Ophthalmoplegia - impaired mobility of the eye; can be determined by one or more reasons.

1. Orbital formation.
2. Restrictive myopathy with thyroid disease of the eye or myositis of the orbit.
3. Lesions of the oculomotor nerve with carotid-cavernous anastomosis, Tolosa-Huni syndrome and malignant tumors of the lacrimal gland.
4. Pincering of extraocular muscles or fasciae with a fracture fracture.
5. Splitting optic nerve fibers with the meningioma of its shell.

The difference between restrictive and neurological ophthalmoplegia

The following tests can help differentiate the restrictive motor dysfunction from the neurological.

The forcible displacement test

• drip drops of anesthetic;
• moisten the cotton wool with an anesthetic solution and place them on both eyes in the area of the muscles being examined for 5 minutes;
• grab the muscle of the affected eye with the tweezers at the attachment site and rotate the eye in the direction of the restriction of mobility.
• repeat the test for a paired eye.

Positive result: difficulty or inability to shift the eye indicates a restrictive cause, such as thyroid myopathy or muscle contraction at the site of the fracture. On the opposite side of the resistance, movement is not observed if the process does not have a two-sided nature.

Negative result: resistance will not be observed in both eyes in case of neurologic pathology and muscle paresis.

The test for determining the difference in intraocular pressure

• intraocular pressure is measured at the normal position of the eye;
• The measurement is repeated in the position of the eye when trying to look towards the limitation of mobility.

Positive result: increased intraocular pressure by 6 mm Hg. Art. And more suggests that resistance is due to muscle restriction.

Negative result: increased intraocular pressure less than 6 mm Hg. Art. Suggests a neurological pathology.

Easy pulsation is best revealed when viewed through a slit lamp and especially when performing applanation tonometry.

The advantage of this test compared with the forced displacement is less discomfort for the patient and a more objective result.

Saccadic eye movements in neurological processes are characterized by a decrease in speed, whereas with restrictive defects sudden stops are observed at the normal speed of this kind of movements.

Causes of visual disorders

1. Exposure keratopathy - the most frequent cause of visual impairment, is secondary in nature due to pronounced exophthalmos in combination with lagophthalmos and the disturbed Bell phenomenon.
2. Compression optical neuropathy is characterized by signs of disturbance from intraocular pressure: decreased visual acuity, color vision and contrast sensitivity, visual field defects, impaired conduction and changes in the optic nerve disk.
3. The folds of the choroid in the macula can sometimes lead to visual disturbances.

Dynamic characteristics

The following dynamic signs can help in the diagnosis of pathology.

1. An increase in venous pressure at a certain position of the head, Valsalva test or compression of the jugular vein may lead to the appearance or increase of exophthalmos in patients with a venous anomaly of the orbit, and also serve as a sign of capillary hemangioma of the orbit in children.
2. Pulsation, the cause of which may be arteriovenous anastomosis or defect of the arch of the orbit.
   • In the first case, ripple is accompanied by noise, depending on the magnitude of the defect.
   • In the latter case, pulsation is transmitted from the cerebral side to the cerebrospinal fluid and noise is not accompanied.
3. Noise is characteristic of carotidio-cavernous fistula. It is better audible with the help of a stethoscope and decreases or disappears when the ipsilateral carotidio artery is squashed.

Changes in the disc of the optic nerve

1. Atrophy of the optic nerve, which may be preceded by its edema, is a manifestation of pronounced compression optic neuropathy. The main causes are thyroid disease of the eye and tumors of the optic nerve.
2. The opticociliary shunts consist of enlarged, normally parapapillary capillaries that shunt the blood from the retinal venous system into the parapapillary choroid, with occlusion of normal drainage pathways. With ophthalmoscopy, the vessels, often of the temporal half, are enlarged and twisted and disappear at the edge of the optic nerve disc. Rarely, this picture can be observed with a tumor of the orbit or optic nerve, squeezing the latter in orbit and disrupting the outflow of blood from the central vein of the retina. Most often shunts occur with meningioma of the optic nerve shell, but can occur with its gliomas and cavernous hemangiomas.

Choroidal folds

This group of parallel alternating light and dark tender lines and striae, most often located in the back pole. Choroid folds are observed in various orbital pathologies, including tumors, distyroid ophthalmopathy, inflammatory processes and mucoceles. The folds are usually asymptomatic and do not lead to a deterioration of vision, although in some patients a shift of refraction towards hypermetropia occurs. Although folds of the choroid are more often combined with pronounced exophthalmos and anterior localization tumors, in some cases their appearance may precede a clinically significant exophthalmos.

Changes in the vessels of the retina

1. The crimp and expansion of veins is characteristic for arteriovenous anastomoses.
2. Vein dilatation can also be combined with a stagnant disc in patients with volume formation of the orbit.
3. Occlusion of vessels can be observed with carotid-cavernous anastomosis, cellulitis of the orbit and tumors of the optic nerve.

Special research methods

1. CT is useful for describing bone structures, localization and size of volumetric formations. Especially valuable in patients with trauma to the orbit, tk. Helps to detect even minor cracks, foreign bodies, blood, extraocular muscle hernia and emphysema. However, CT is poorly informative in the differentiation of various soft-tissue structures "having the same radiographic density.
2. MRI can visualize the processes at the apex of the orbit and the spread of orbital tumors into the cranial cavity. STIR - a mode of suppression of fat at Tl-weighted tomography - is very valuable for definition of activity of inflammatory process at a thyroid disease of an eye.
3. Radiographs with the advent of CT and MRI partially lost their significance. There are 2 main projections:
   • Caldwell projection, in which the nose and forehead of the patient touch the film. It is most often used for orbital lesions;
   • the projection of Waters, when the patient's chin is slightly elevated, is useful in diagnosing fractures of the lower orbital wall.
4. Fine needle biopsy is performed under CT control using a needle. This technique is especially necessary for patients with suspicion of metastatic orbital damage and with the emergence of tumors from adjacent structures into orbit. When performing a biopsy, complications can occur in the form of hemorrhage and perforation of the eye.

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