Accommodation paralysis is a disorder in which, due to refractive errors, it is temporarily impossible to change the optical installation of the eyeball. Clinical manifestations include decreased visual acuity in the vicinity, increased visual fatigue, difficulty concentrating when looking at closely located objects. Diagnostics is based on computer refractometry, visometry, and the study of the accommodative ability of the eyes. Cholinomimetics or antagonists of a-adrenergic receptors can be used in the treatment. In case of injury to the pupillary sphincter or ciliary muscle, surgical treatment is indicated.
H52.5 Accommodation disorders
Accommodation paralysis is an opticoneurosis that is quite rare in practical ophthalmology. Pathology is most common among children aged 7-15 years, less often diagnosed in middle-aged and elderly people. According to statistics, in 60-70% of cases, the mechanism of disease development is based on the use of cycloplegics. In infections, a violation of the accommodative ability is usually considered as a transient phenomenon. The prevalence in the general structure of ophthalmic diseases has not been studied. Male and female individuals suffer with the same frequency. Accommodation disorders are ubiquitous.
It is believed that the disease can be provoked by psychoemotional overstrain. Scientists are studying the relationship between the onset of symptoms and metabolic disorders in diabetes. Temporary paralytic phenomena are observed in acute alcohol intoxication. In patients with chronic alcoholism, both eyes are affected symmetrically. The list of the main causes of pathology includes:
- Infectious diseases. Accommodation paralysis often becomes one of the manifestations of botulism, caused by the toxic effects of botulinum toxin. Bilateral lesion is also detected in patients with diphtheria, syphilis and influenza.
- The use of cycloplegics. Transient symptoms develop during instillation into the conjunctival cavity of M-cholinolytics (atropine). Frequent use of drugs of this group can lead to irreversible pupil dilation.
- Traumatic injuries. The appearance of symptoms is associated with direct or indirect traumatic damage to the ciliary muscle in traumatic brain injury. The disorder is often observed with contusion of the eye.
- Diseases of the brain. Persistent visual dysfunction may indicate the formation of brain formations (tumor, cyst, abscess). The clinic of transient paralysis is characteristic of meningitis or meningoencephalitis.
- Iatrogenic intervention. Manifestations occur when the ciliary nerves are damaged during laser coagulation of the retina. The trigger factor is laser or electrical stimulation of the ciliary muscle. In rare cases, paralysis is a complication of local barotherapy.
Accommodation paralysis develops due to direct or indirect damage to the ciliary muscle and the pupil sphincter. Both structures are innervated by parasympathetic nerve fibers from the ciliary node. This explains the fact that binocular disorder is diagnosed with an apparently intact eyeball. In the monocular variant, accommodation dysfunction is observed, which is also called “accommodation inequality”. The cause of its occurrence is a direct lesion of the ciliary muscle or pupillary sphincter.
Pathology manifests acutely or subacutely. Patients often associate the occurrence of symptoms with stress, infectious diseases or the use of eye drops. There are complaints of pronounced visual impairment near, very rarely – in the distance. The reason for contacting an ophthalmologist is the inability to perform the usual visual work (reading, writing, watching TV) at a close distance, to concentrate on one subject. Patients clearly indicate the time of development of the first symptoms. More often, vision decreases symmetrically, but cases of unilateral lesion are described. The disease is prone to recurrent course. If the cause is a brain lesion, the clinical picture is dominated by meningeal symptoms, represented by nausea, indomitable vomiting, severe headache.
The diagnosis is based on anamnesis data, objective examination and the results of instrumental techniques. Visually, one- or two-sided dilation of the pupils is revealed. When the ciliary muscle is injured, foci of subconjunctival hemorrhage are visible. No other changes from the anterior segment of the eyeball are detected. Specific diagnostic methods are:
- Computer refractometry. Emmetropic or hypermetropic type of clinical refraction is determined. With hypermetropia, there is a discrepancy between the vertical and horizontal axes.
- Visometry. During correction, visual acuity remains high in the distance, rarely decreases. A decrease to 0.1 dptr and below is confirmed nearby. With the auxiliary use of convex glasses, vision improves.
- Accommodation research. Standard sets of negative and positive lenses are used. It turns out to be impossible to study the volume of the accommodative ability of the eyeball, since the nearest point of clear vision merges with the further one.
Differential diagnosis is carried out with a weakness of accommodation and presbyopia. When accommodation is weak, patients cannot clearly indicate the time frame for the appearance of the first symptoms, acute manifestation is characteristic of paralysis. With presbyopia, clinical manifestations develop in adulthood or old age. Their severity increases gradually, which is atypical for paralysis.
Often therapy does not have the proper effect, paralysis is spontaneously leveled for 2-3 months. Visual acuity is restored spontaneously. The patient’s management tactics are strictly individual, determined by the etiology of the disease. With the medical origin of the pathology, visual functions are normalized after the completion of the pharmacological action of cycloplegic or exposure to bacterial and viral toxins. The process can be accelerated by instillation into the conjunctival cavity of medicines based on digitalis glycoside. In the absence of an effect, the use of cholinomimetics or antagonists of a-adrenergic receptors is indicated. In case of traumatic ruptures of the ciliary muscle or sphincter, surgical treatment is recommended, which is reduced to the comparison of the edges in the conditions of clinical mydriasis.
Prognosis and prevention
In most cases, the prognosis for accommodation paralysis is favorable. After the end of the action of pathogenic factors (toxins, medications), visual acuity is fully restored. If the pathology is based on organic lesions of the pupil sphincter and ciliary muscle, hypermetropia may develop. Myopia never becomes the outcome of the disease. Specific preventive measures have not been developed. Non-specific prevention is reduced to the prevention of uncontrolled use of eye drops. Patients with infectious diseases (botulism, influenza, diphtheria) are subject to examination by an ophthalmologist.