Double Vision : Causes, Symptoms, Diagnosis & Treatment

• Causes Of Double Vision
• Astigmatism
• Pathologies Of Convergence
• Accommodation Disorders
• Neurological Disorders
• Orbital Myositis
• Thyroid Ophthalmopathy
• Injury
• Postoperative Complications
• Taking Medication
• Intoxication
• Diagnostics
• Treatment
• Help Before Diagnosis
• Conservative Therapy
• Surgery

Double vision (diplopia) is the simultaneous visualization of two images of the same object. Double vision occurs with violations of refraction, accommodation and convergence, neurological diseases, intoxication and injuries. Methods for diagnosing diplopia include visometry, computerized autorefractometry, biomicroscopy, ophthalmoscopy, MRI, radiography, laboratory tests, and pharmacological tests. For immediate elimination of a diplopia occlusion of one eye is shown. Etiotropic treatment is determined by the underlying disease.

Causes of double vision

Astigmatism

With astigmatic refraction, diplopia is monocular, therefore, when one eye is closed, complaints do not disappear. Patients note a difference in the intensity of the images in front of their eyes. One of them (usually true) looks sharper, and the second looks like a shadow. It seems that the two objects partially overlap each other. When correcting astigmatism, double vision becomes less pronounced or disappears altogether.

Pathologies of convergence

Normally, due to convergence (simultaneous movement of the eyeballs towards each other), binocular vision is maintained when viewing objects close up. When this mechanism is violated, the images from each of the eyes are incorrectly focused on the retina. Common causes of double vision:

• The kurtosis of convergence . Diplopia appears when looking into the distance and may be accompanied by a decrease in visual acuity, discomfort or pain in the eyes. When you try to examine an object, the effect of its oscillation is created, which is due to oscillopsia.
• Lack of convergence . Double vision occurs up close. People have difficulty reading and writing. Prolonged work at close range leads to pain, increased fatigue and a desire to “rub” the eyes.

Accommodation disorders

Accommodation is the ability to see objects located at different distances from a person. Symptoms of deterioration in accommodative ability are usually non-specific and require a detailed history taking. Double vision is characteristic of the following disorders:

• accommodation insufficiency . Patients complain of deterioration in near vision, difficulty in focusing on an object that quickly changes location. Concomitant manifestations: monocular diplopia, headache, photophobia.
• The kurtosis of accommodation . Characterized by double vision and decreased distance visual acuity. Nearby functions are not affected. Patients note the periodic development of pain in the forehead, the appearance of micropsia.
• Spasm of "near vision" . There is a spasm of accommodation, which reaches 8-1 diopters and pronounced miosis. Esotropia is associated with bilateral abduction restriction. Horizontal diplopia persists both at close and far distances.

Double vision

Neurological disorders

Double vision is a common symptom of diseases of the central and peripheral nervous system. The mechanism of development is based on an indirect lesion of one or more oculomotor muscles. Symptoms may be permanent, transient, or recurrent. The most common causes:

• Paralysis of the abducens nerve . Due to paresis of the lateral rectus muscle, esotropia develops. Horizontal diplopia is more noticeable at a great distance. Depending on the etiology, dysfunction is temporary or permanent.
• Paralysis of the trochlear nerve . Paresis of the superior oblique muscle provokes vertical, oblique or rotatory diplopia. Complaints of double vision occur when looking down. The contralateral tilt of the head is due to a compensatory mechanism.
• intracranial hypertension. An increase in intracranial pressure (ICP) is accompanied by the development of asymmetric bilateral horizontal diplopia. Its severity correlates with the indicators of ICP.
• Ocular neuromyotonia . An attempt to keep the eyes in an eccentric position potentiates episodic double vision. Patients develop involuntary, sometimes painful contractions of the extraocular muscles.
• Myasthenia. The clinical picture is represented by unilateral or bilateral ptosis and diplopia, which are more noticeable in the afternoon than in the morning or after rest. Systemic manifestations often include dysphagia, dysarthria, dysphonia, and dyspnoea.

Orbital myositis

Orbital myositis results in diffuse involvement of one or more oculomotor muscles, which limits eye movement. Patients report sudden onset of diplopia, chemosis, and conjunctival vascular injection. Pain in the orbital area is barely perceptible with the involvement of one muscle and unbearable with a common process. In severe cases, proptosis can be traced.

Thyroid ophthalmopathy

Most often, the lower rectus muscle is involved in the pathological process, so the direction of diplopia is vertical. Double vision is determined in the position of the head with a raised chin. Other external muscles of the eye may also be involved. Symptoms worsen in the morning, allowing differential diagnosis with orbital myositis. Dysfunction of the medial rectus muscle against the background of thyroid ophthalmopathy mimics the clinic of abducens nerve palsy.

Injury

Traumatic damage to the walls of the orbit leads to displacement of the eyeball, which leads to diplopia, pain during eye movements and swelling of the soft tissues. As the edema decreases with a fracture of the inferior wall of the orbit, the severity of diplopia often increases. Double vision is unbearable, often accompanied by dizziness, headache. In order to eliminate it, patients close one eye.

Postoperative complications

Diplopia can occur after surgical treatment of strabismus, cataracts, retinal detachment. In cataract surgery, the causes are anisometropia, astigmatism, dislocation of the intraocular lens. Excessive correction of strabismus is complicated by doubling, which in childhood potentiates the development of amblyopia. Vitreoretinal interventions that lead to a change in the profile of the retina are manifested by monocular diplopia, a distortion of the image before the eyes.

Taking medication

Long-term use of beta-blockers to reduce intraocular pressure leads to diplopia, ptosis, internuclear ophthalmoplegia, and severe general weakness. Double vision is observed within a few days or weeks after changing the dosage or type of glucocorticosteroids. Associated symptoms: nausea, vomiting, headache and increased drowsiness.

Intoxication

Double vision is common with the abuse of drugs, alcohol, or medication with the intent to commit suicide. Regardless of the underlying cause, the clinical picture of the intoxication syndrome is represented by headache, confusion, dizziness. Specific signs are determined if the poisoning provoked:

• Cocaine. Leading symptoms of overdose: diplopia and a feeling of excessive anxiety. The skin becomes pale, moist, cold to the touch. There is marked mydriasis. Perhaps an increase in body temperature, the development of nausea and vomiting. Clonic-tonic convulsions appear.
• Ethylene glycol. Acute poisoning is manifested by double vision, dilated retinal veins and blanching of the optic discs. Pupils sluggishly react to light. With prolonged exposure to vapors, the mucous membrane of the eyes and upper respiratory tract is affected.
• Gelsemium evergreen. All parts of the plant contain toxic alkaloids associated with strychnine - gelsemin and gelseminin. Along with diplopia, skin irritation is observed. The most common cause of intoxication is the sucking of nectar from a flower, which is mistaken for honeysuckle.

Diagnostics

During the initial examination by an ophthalmologist, the type of diplopia is first established. If the symptoms disappear when one eye is closed, then we are talking about the binocular form. With the monocular variant, double vision persists when the other eye is closed. To establish the etiology of diplopia, specific examination methods are performed:

• Visometry. Visual acuity is measured at a distance and at the working distance of the patient with and without correction. In this case, it is necessary to find out at what distance doubling occurs and whether its characteristics change with glasses or when the head is tilted.
• Computer autorefractometry. Subjective refraction is being studied with the selection of a trial correction. After instillation of cycloplegics, the study is repeated to obtain objective refractive indices.
• Biomicroscopy of the eye. It is necessary to examine in detail the anterior segment of the eye and assess the state of the refractive media of the eyeball. In pseudophakia, the position of the intraocular lens should be determined.
• Ophthalmoscopy. Examination of the fundus reveals signs of intracranial hypertension (stagnation of the optic disc, dilated tortuous veins, narrowed arteries). After vitreoretinal interventions, the surface of the retina may be distorted.
• MRI of orbits and optic nerves. The technique makes it possible to visualize thickening of the oculomotor muscles, which is observed in orbital myositis and thyroid ophthalmopathy. With concomitant proptosis, it is important to exclude pathological changes in the fiber.
• Orbital x-ray. It is performed in direct and lateral projection in the presence of a clinic of fracture of the bone walls of the orbit. If the diagnosis is difficult, computed tomography is recommended.
• Laboratory Research . If thyroid ophthalmopathy is suspected, measurement of TSH, T3, free T4 and the level of antibodies to thyrotropin receptors is indicated. In myasthenia, the level of autoantibodies to the muscle acetylcholine receptor should be assessed.
• pharmacological tests. The essence of the tests is reduced to the subcutaneous administration of an anticholinesterase drug in the clinical picture of myasthenia gravis. The sample is considered positive with full or incomplete compensation of clinical signs.

Ophthalmic diagnostics

Treatment

Help before diagnosis

Unilateral occlusion is used to eliminate diplopia and associated symptoms at the diagnostic stage. It should be remembered that these are temporary measures that are recommended until the etiology is determined. There are different options for occlusion: eye patch, frosted lenses for glasses, contact lenses with an opaque center, special occluders.

If there are signs of intoxication, you should immediately call an ambulance. The patient is transported in a sitting position or on his side. It is important to perform a gastric lavage in a timely manner and introduce an antidote. In acute poisoning with narcotic analgesics, naloxone hydrochloride is used. The universal antidote is sodium dimercaptopropanesulfonate monohydrate (unithiol).

Conservative therapy

An important role is given to timely etiotropic therapy of the underlying disease. With thyroid ophthalmopathy, treatment is carried out by an ophthalmologist together with an endocrinologist and is aimed at achieving euthyroidism. The tactics of patient management is developed individually, but in most cases it involves the use of synthetic analogues of thyroid hormones and glucocorticosteroids.

In myasthenia gravis, drug treatment is aimed at compensating for neuromuscular transmission disorders and correcting immune disorders. The introduction of immunoglobulin G, anticholinesterase agents and glucocorticosteroids is shown. Also, the complex of therapy includes the intake of potassium chloride and spironolactone.

Double vision often occurs against the background of refractive errors. When they are identified, the appointment of spectacle correction or soft contact lenses is indicated. Orthoptic treatment is recommended for convergence disorders. If diplopia persists, then it is advisable to apply a prismatic correction.

Surgery

Surgical interventions on the extraocular muscles are carried out if no positive dynamics is observed for at least 6 months, and the cause of diplopia is cranial nerve palsy. With vision-threatening thyroid ophthalmopathy, decompression is performed. Fractures of the bone walls of the orbit require reconstructive interventions. If after the operation there is residual diplopia, the use of Fresnel lenses is recommended.