Mydriasis
The content of the article:
- Causes
- Forms
- Signs
- Diagnostics
-
Treatment
- Drug therapy
- General recommendations
- Surgery
- Prevention
- Consequences and complications
Mydriasis is the dilation of the pupil. The pupil reacts to light levels by expanding (if there is not enough light) or narrowing (in bright light) - this is a physiological process. Pupils can respond with an increase in size not only to external, but also to internal changes, for example, they expand when a person is under stress. After dilating, the pupil returns to its normal state. But mydriasis is also pathological, when the subsequent narrowing does not occur, in this case it acts as a symptom of the disease.
With mydriasis, the pupil increases to 7-10 mm
Causes
Physiological dilation of the pupil occurs when there is insufficient light and when looking into the distance. When a person experiences severe stress, under the influence of the sympathetic nervous system, mydriasis occurs, the eyes (pupils) dilate - the saying “fear has big eyes” is about this. This reaction is normal and aims to improve vision.
Physiological dilation of the pupil is caused by the following factors:
- lack of lighting;
- emotional arousal (both positive and negative);
- great surprise; increased attention to something;
- look into the distance;
- a reaction to a surprise, such as a sharp loud sound;
- deep breath.
Mydriasis can be medicinal or medicinal. In this case, he is called specifically, so that the ophthalmologist can conduct an examination of the fundus or perform surgery. Dilatation of the pupils is achieved by instillation (instillation) into the eye of a drug that causes temporary paralysis of the sphincter of the pupil - the circular muscle that constricts the pupil. These drugs include Midriacil, Irifrin, Tropicamide. Atropine has a similar effect, but it is used less often, since its effect lasts much longer, up to two weeks, which can lead to significant inconvenience for the patient. Sometimes drug mydriasis can be a side effect of therapy, for example, in the treatment of accommodation spasm.
The causes of pathological mydriasis are many, including:
- intoxication with chemicals, carbon monoxide;
- overdose (intoxication) with certain drugs (Atropine, Scopolamine, Platyphyllin, Ephedrine);
- drug use (hallucinogens, cocaine, ecstasy, methamphetamines, cannabis);
- diseases of the central nervous system (brain tumors, dislocation syndrome, stroke);
- fractures of the base of the skull or orbit;
- spinal cord injury;
- trauma to the eyeball;
- acute oxygen deficiency;
- aneurysm of the posterior communicating artery;
- near-death condition, coma;
- preeclampsia (pregnancy complication);
- congenital pathologies (hydrocephalus);
- ophthalmic diseases (glaucoma, myopia, iridoplegia, inflammation of the optic nerve, iridocyclitis, Bumke's syndrome, Purfur du Petit syndrome, blindness of various etiologies, paralysis of the ciliary muscle);
- infectious diseases (tuberculosis, neurosyphilis, botulism, diphtheria, viral infections);
- pathology of the nervous system (Adi's syndrome, epilepsy, Parkinson's disease, sympathicotonia, encephalopathy, migraine, cranial nerve neuropathy);
- systemic diseases (multiple sclerosis);
- diseases of internal organs (renal and hepatic failure, heart and lung diseases, some pathologies of the digestive system);
- metabolic disorders (thyroid pathology, diabetes mellitus).
Forms
The above described physiological, medicinal, pathological mydriasis. In addition, it can be unilateral and bilateral, asymmetric and symmetrical, transient or permanent.
According to the mechanism of development, the following types of mydriasis are distinguished;
| A type | Characteristic |
| Physiological | Always bilateral, symmetrical and temporary. |
| Medication | Iatrogenic origin, does not pose a danger, stops after the action of the drug. |
| Paralytic | Caused by paralysis of the sphincter of the pupil. It can occur when the oculomotor nerve is damaged, usually caused by pathologies of the central nervous system (neurosyphilis, epilepsy, Parkinson's disease, hydrocephalus, etc.). |
| Spastic |
It is caused by a spasm of the pupil dilator muscle (the muscle that dilates the pupil), which occurs in response to irritation of the cervical part of the sympathetic trunk, can also be the result of severe intoxication or disease of the internal organs. With this type of mydriasis, the reaction to light and distance is preserved. |
| Traumatic | It can be caused, among other things, by an operating injury. Postoperative mydriasis can persist for years, in this case, iris plastic is performed to eliminate it. |
| Adi's syndrome | It is caused by the defeat of the ciliary ganglion in a number of diseases. Pupil dilation is unilateral. Recovery is long, sometimes it takes several years. |
Signs
The main symptom of mydriasis is the dilation of the pupil up to 7-10 mm (normally its diameter is from 2 to 5 mm). If the subsequent contraction of the pupil does not occur, this condition is accompanied by symptoms from the organ of vision and general.
Visual symptoms:
- increased photosensitivity, intolerance to bright light;
- lack of reaction to light;
- lack of reaction to an object approaching the eye;
- decreased visual acuity;
- burning, pain in the eye (or both eyes, if mydriasis is bilateral);
- rapid eye fatigue;
- lacrimation;
- violation of eye movement in one or more planes;
- discomfort, pain when reading, watching TV, working at a computer.
With prolonged mydriasis, the following may appear:
- deformation of the pupil, it acquires a pear-shaped, tear-shaped or sharply oval shape (slightly oval pupils may be normal);
- ptosis (drooping of the eyelid);
- strabismus.
Pupil deformity with mydriasis
Common symptoms accompanying pathological dilation of the pupils:
- headache;
- dizziness;
- sleep disorders;
- emotional instability, anxiety.
Mydriasis caused by a certain disease is accompanied by the symptoms characteristic of this disease.
In children, pathology manifests itself in the same way as in adults.
Diagnostics
By itself, mydriasis does not require special diagnostic methods, as it is detected visually. However, a thorough examination is necessary to identify its cause, without which treatment is impossible.
Primary diagnosis consists in taking anamnesis, clarifying concomitant symptoms, events preceding mydriasis, as well as an ophthalmological examination with mandatory ophthalmoscopy.
The patient is assigned laboratory tests:
- clinical (general) blood test;
- clinical analysis of urine;
- blood chemistry;
- blood test for hormones, primarily thyroid hormones.
Instrumental diagnostics includes:
- CT (computed tomography) and / or MRI (magnetic resonance imaging) of the head;
- Ultrasound (ultrasound examination) of the abdominal organs;
- ECG (electrocardiography);
- chest x-ray.
Further diagnosis depends on what will be found on the basis of the examination. Depending on the nature of the identified pathology, it may be necessary to consult related specialists: a neurologist, neurosurgeon, endocrinologist, traumatologist, etc.
Treatment
Physiological and drug mydriasis does not require treatment, in this case, the dilation of the pupils passes on their own after the etiological factor stops acting.
Pathological mydriasis is not an independent disease, but a symptom of any pathology, therefore, etiotropic treatment consists in measures aimed at the underlying disease.
Drug therapy
To eliminate mydriasis, in some cases, the use of drugs that weaken the effect of the dilator and stimulate the sphincter of the pupil may be indicated. For this purpose, drugs of the following groups can be prescribed:
- alpha-blockers (Tropafen, Prazosin, Phentolamine);
- M-cholinomimetics (Pilocarpine, Aceclidine);
- N-cholinomimetics (Cititon, Lobelin).
Pilocarpine is a drug that in some cases is used to eliminate mydriasis
Depending on the underlying disease, they can also be prescribed:
- diuretics;
- nootropic drugs;
- antiplatelet agents; and etc.
General recommendations
With pathological dilation of the pupils, the following restrictions must be observed:
- Avoid too bright lighting, exposure to the sun;
- Wear dark glasses outdoors;
- Refuse to drive a car during treatment, read long texts, work at a computer.
- Quit smoking, alcohol and psychoactive substances.
- Refuse self-medication, drug abuse. Take any medications only as directed by a doctor, strictly observing the prescribed dosage.
Surgery
Surgical treatment is indicated in cases where it is required by the causative disease, mainly:
- tumors or cysts of the brain;
- hematomas or brain abscesses;
- aneurysm of the posterior communicating artery.
Prevention
In order to prevent mydriasis, it is recommended:
- Refusal to use alcoholic beverages, psychoactive substances, smoking.
- The use of any medication as prescribed by a doctor in compliance with the prescribed dosage.
- Avoiding eye injuries (protection with special glasses at work, etc.) and head.
- Early detection and treatment of diseases that can lead to pathological dilation of the pupils.
- Passing preventive examinations with an ophthalmologist, in the presence of unpleasant symptoms associated with the eyes, immediately contact a specialist.
Consequences and complications
Long-term mydriasis in the absence of treatment can lead to a significant decrease in vision and a deterioration in the quality of life in general.
Anna Kozlova Medical journalist About the author
Education: Rostov State Medical University, specialty "General Medicine".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
