Exophthalmos is a mono or binocular displacement of the eyeball forward. Common symptoms for most forms are obstructed eye movements, diplopia, burning sensation and pain due to increased dryness of the conjunctiva. Diagnosis of exophthalmos is based on the collection of anamnesis, external examination, exophthalmometry, ophthalmoscopy, visometry, tonometry, biomicroscopy, Doppler ultrasound, OCT. Treatment tactics depend on the etiology of the disease. In case of traumatic genesis, cantotomy, drainage of the retrobulbar space is recommended. Endocrine exophthalmos is an indication for taking thyrostatics and hormones, with low efficiency, thyroidectomy is performed.
Exophthalmos is a pathological protrusion of the eyeball from the orbital cavity, not accompanied by an increase in its longitudinal size. Pathology was first described as a symptom of endocrine ophthalmopathy in 1776 by the Irish surgeon R. J. Graves. In 1960, Soviet neurosurgeons I. M. Irger and L. A. Koreish presented information that the displacement of the eyeballs anteriorly can occur with pathological neoplasms of the cerebellum. Exophthalmos of endocrine nature is 6-8 times more common among females, the post-traumatic genesis of the disease is more typical for men. Clinical manifestations of exophthalmos are widespread in all age groups.
Causes of exophthalmos
Strictly speaking, exophthalmos is not an independent disease, but usually acts as a symptom of another primary pathology. Both systemic (autoimmune, endocrine) and local (ocular) pathologies can lead to protrusion of the eyeball:
- Endocrine ophthalmopathy. The mechanism of pathology development is based on the dysfunction of the immune system, in which there is swelling of the subcutaneous fat of the orbit and the external muscles of the eyeball (edematous form). At this stage, the manifestations of exophthalmos may undergo reverse development. The progression of the disease leads to the formation of scar defects in the oculomotor muscles, which provokes irreversible changes. Autoimmune damage of retrobulbar fiber in Graves’ disease is caused by the mechanism of cross-reaction of the body’s antibodies to thyroid antigens and orbital tissue. Confirmation of the thyrotoxic theory of pathogenesis is the increased titer of antibodies to RTG.
- Local autoimmune processes. Less often, the development of exophthalmos is caused by an isolated autoimmune lesion of retrobulbar tissue. In this case, pathological antibodies are synthesized to the muscles of the oculomotor apparatus, fibroblasts and the cellulose of the orbit. A specific marker of the disease is antibodies to periorbital fiber, because immunoglobulins to myocytes are detected only in some patients. Exposure to factors such as stress, viruses, toxic substances and radiation in genetically compromised individuals stimulates the production of antigens.
- Mechanical factors. With inflammation of the fatty tissue or vasculitis of the vessels of the orbit, a mechanical cause of bulging of the eyeball occurs. Less often, the etiological factor of exophthalmos becomes dacryoadenitis, benign or malignant neoplasms. Varicose veins, angiopathy or traumatic injuries can lead to displacement of bone fragments or hemorrhage into the orbital cavity, which provokes the development of a clinical picture of pathology.
According to the clinical classification, there are constant, pulsating and intermittent exophthalmos. Pathology often proceeds binocularly, however, in the initial stages, monocular lesion is possible. According to the dynamics of development, there is a non-progressive, slowly and rapidly progressing, regressive displacement of the eyeball anteriorly:
- a slow increase in the clinical picture is indicated by an increase in the size of the eyeball by 1-2 mm for 1 month;
- with rapid progression, the size of the eye increases by more than 2 mm in less than 30 days.
Symptoms of exophthalmos
Exophthalmos can be a symptom of many diseases. The clinical picture is determined by the degree of displacement of the eyeball anteriorly. The diameter of the eyeball 21-23 mm corresponds to the I degree, 24-26 – II degree, 27 and more – III degree of exophthalmos.
At grade I, the disease may be asymptomatic. It is possible to identify pathological changes in the organ of vision only with a special examination. With grade II exophthalmos, patients complain of obstructed movements of the eyeballs, double vision. With a unilateral lesion, a clinical picture of strabismus develops. A specific symptom of the intermittent form of the disease is an increase in the manifestations of exophthalmos with respiratory retention, head tilts, compression of the jugular vein.
The III degree of the pathological process significantly complicates the process of closing the eyelids. As a result, the production of secretions by the meibomian glands is disrupted, which, together with the inability to blink and close the eyes, leads to increased dryness of the orbital conjunctiva. At the same time, patients complain of a burning sensation and pain in the eyes. The progression of exophthalmos is complicated by secondary keratopathy with subsequent formation of ulceration sites. Clinical manifestations are hyperemia, soreness, photophobia. Increased lacrimation is also possible, which increases the traumatization of the cornea.
With the III degree of lesion, compression of the optic nerve disc occurs, therefore, the common symptoms of pronounced exophthalmos are a progressive decrease in visual acuity up to complete blindness, pain syndrome with irradiation to the frontal lobes and brow arches.
Diagnosis of exophthalmos is based on anamnestic data, results of external examination, exophthalmometry, ophthalmoscopy, visometry, tonometry, biomicroscopy, ultrasound diagnostics (ultrasound) in In-mode, optical coherence tomography (OCT). Anamnestic information often indicates the etiology of the disease (traumatic injuries, allergic reactions, pathological neoplasms). An external examination determines the bulging of the eyeballs from the socket, the monocular lesion is accompanied by strabismus. Instrumental examination:
- Exophthalmometry. It is carried out with the help of a Hertel exophthalmometer. This method allows you to determine the severity of exophthalmos.
- Ophthalmoscopy. In the third degree of pathology, the ophthalmoscopic picture corresponds to compression of the optic nerve disc (OND). At the same time, pale or edematous OND is visualized, small areas of hemorrhage are less often observed.
- Biomicroscopy. With this method, it is possible to identify superficial keratopathies, areas of ulceration of the cornea.
- Tonometry. During tonometry, the level of increase in intraocular pressure is determined, which, as a rule, deviates from the reference values for the II-III degree of the disease. With the development of secondary complications of exophthalmos (OND compression), there is a progressive decrease in visual acuity.
- OCT. According to optical coherence tomography, swelling of the periorbital fiber, pathological neoplasms inside the eye socket, areas of hemorrhage are visualized.
- Doppler ultrasound. Echography in B-mode allows you to determine the degree of exophthalmos, assess the condition of the surrounding tissues. The ultrasound method is recommended in ophthalmology for monitoring the progression or regression of the disease in dynamics.
If exophthalmos is one of the symptoms of thyroid pathology, it is recommended to determine the level of thyroxine, triiodothyronine, thyroid-stimulating hormone, and also to conduct an ultrasound examination of the gland.
Treatment of exophthalmos
The tactics of treatment of exophthalmos is determined by the etiology and severity of the disease. In case of traumatic origin, in the absence of movements of the eyeball, it is recommended to perform a canthotomy in the area of the external adhesion of the eyelids to achieve decompression. 0.5 ml of 2% novocaine solution is used as regional anesthesia. Before dissecting the ligament, it is fixed with a special hemostatic clamp. The incision line is extended to the bony edge of the orbit. If the mobility of the eyeball is preserved, but due to massive hemorrhage, intraocular pressure increases rapidly, drainage of the retrobulbar space is required.
With the development of exophthalmos in patients with endocrine ophthalmopathy, the goal of therapy is to achieve an euthyroid state. To do this, the hormonal balance is corrected with the help of thyrostatics and hormones. During the treatment period, it is necessary to moisten the conjunctiva in a timely manner with the help of artificial tear preparations, carry out daily monitoring and, if necessary, correction of intraocular pressure.
In the case of the autoimmune nature of exophthalmos, the complex of therapeutic measures includes taking glucocorticoids. If drug therapy does not have the desired effect, removal of the thyroid gland with subsequent hormone replacement therapy is recommended.
Prognosis and prevention
The prognosis for exophthalmos depends on the etiology. With an endocrine nature, the course of the disease after hormonal correction is favorable. Displacement of the eyeball in malignant intraorbital neoplasms, tumors of the cerebellum is associated with an unfavorable prognosis.
Specific measures for the prevention of exophthalmos in ophthalmology have not been developed. Non-specific preventive measures are reduced to the correction of hormonal imbalance, compliance with safety regulations at work. All patients with suspected exophthalmos should be examined by an ophthalmologist. Violation of visual functions in this pathology is determined by the degree of compression of the optic nerve disc.