Lagophthalmos is an ophthalmopathology in which the process of closing the eyelids is disrupted. Clinically, the disease is manifested by conjunctival hyperemia, foreign body sensation, burning sensation, photophobia, decreased visual acuity, increased dryness and lacrimation. A visual examination is sufficient to make a diagnosis. Biomicroscopy of the eyes, visometry, ultrasound and OCT are performed to assess the condition of the eyeball structures. Conservative therapy includes the local use of medicines and special bandages. Surgical treatment is reduced to reconstructive surgical interventions (neurolysis, autotransplantation, reinnervation) or tarzo- and blepharography.
Lagophthalmos is a common ophthalmopathology of often paralytic genesis. Violation of eyelid closure on the background of paralysis or paresis occurs with a frequency of 30:100,000 of the population. There are no statistical data on the epidemiology of other forms. In 60% of cases, the disease develops against the background of neuritis of the facial nerve of unknown origin. In males and females, it is diagnosed in a ratio of 1:1. Geographical and seasonal features of the spread of pathology have not been established. Lagophthalmos is of great social importance due to the high risk of disability of the patient.
Violation of the process of closing the eyelids is a consequence of an anomaly of the structure, a disorder of innervation or the influence of mechanical factors. The main etiological factors of the development of lagophthalmos:
- Paresis and paralysis of the facial nerve. They lead to a violation of the innervation of the circular muscle of the eye, which is normally responsible for the mobility of the eyelids. They are the result of serious diseases, injuries or surgical interventions.
- Defeat of the trigeminal nerve. The V pair of cranial nerves belongs to the mixed group by structure, therefore, when it is affected, not only motor function suffers, but also pain, temperature and tactile sensitivity. The causes of development are the same as with the defeat of the facial nerve.
- An anomaly of development. Lagophthalmos as a secondary pathology may occur in patients with simblepharone and coloboma. With simblepharone, the fusion of the palpebral and orbital conjunctiva prevents the normal closing of the eyes. With coloboma, the conjunctiva is not covered in the cleavage zone.
- Exophthalmos. Due to the displacement of the eyeball anteriorly, the eye slit does not close even with normal anatomical and physiological features of the organ of vision.
- Cicatricial eversion. In ectropion, incomplete closure of the eye slit is caused by sagging of the lower eyelid.
- Retraction of the upper eyelid. The disease is accompanied by a displacement of the skin fold in the direction of the upper edge of the eye socket, manifested by the exposure of the sclera.
Normally, the contraction of the circular muscle ensures the closure of the eyes. In case of violation of the sensory (trigeminal nerve) or motor (facial and oculomotor nerves) innervation, the process of neuromuscular impulse transmission is not realized, the absence of contraction of the circular muscle is manifested by lagophthalmos. The eye slit opens thanks to a group of antagonist – levator muscles, so this function does not suffer. At the same time, the antagonistic contracture of the muscle that raises the eyelid aggravates the clinical manifestations of lagophthalmos. Less often, closure is impossible due to the pathology of the structure. A decrease in the amplitude of blinking movements prevents the uniform distribution of lacrimal fluid on the surface of the conjunctiva, therefore, patients are concerned about increased dryness. The development of xerophthalmia potentiates the inversion of the lower lacrimal point, due to the displacement of the lower eyelid and a decrease in turgor.
In ophthalmology, a clinical classification of pathology according to the degree of severity has been adopted:
- Weak degree. It is characterized by a slight expansion of the eye slit and a drooping edge of the lower eyelid. In the medial third, the smoothness of the skin is determined. The patient is able to close his eyes almost completely. In a dream, the eye slit is slightly open.
- The average degree. Clinical manifestations are more pronounced than with a mild degree, accompanied by a decrease in skin folding. The patient makes efforts to close the eyes. The process of closing the eye slit requires additional involvement of the orbital part of the circular muscle. During sleep, the eyes are open.
- A strong degree. The eye is constantly in an open state. There is an increased dryness of the conjunctiva and cornea, which leads to inflammatory and dystrophic lesions of the organ of vision.
In the initial stages, the disease is manifested by incomplete closure of the eye slit with concomitant dryness of the conjunctiva. Patients report tearfulness, burning sensation and redness of the conjunctiva. The progression of lagophthalmos leads to the fact that the upper eyelid does not fall and does not take part in blinking. Hyperemia of the orbital conjunctiva is most pronounced in the morning, because during sleep, the eye slit is open. Patients complain of “blurring” of vision. Increased lacrimation in lagophthalmos is accompanied by photophobia. With the loss of the corneal reflex, corneal irritation does not cause the eyes to close.
The clinical course of the disease depends on the etiology. Paralysis of the circular muscle provokes the development of ectropion. The displacement of the lacrimal point is manifested by increased lacrimation, the early appearance of symptoms of blepharitis or sluggish conjunctivitis. The occurrence of lagophthalmos with a lesion of the trigeminal nerve is characterized by a violation of tear production. Damage to the VII pair of cranial nerves causes a feeling of dryness and a feeling of a foreign body. The prolonged existence of paralysis potentiates the progression of atrophic changes, manifested by a decrease in the turgor of the eyelids, their downward displacement or inversion.
In 30-40% of cases, lagophthalmos is complicated by xerophthalmia (dryness of the cornea and conjunctiva). The progression of the disease leads to catarrhal conjunctivitis and neurotrophic keratitis. Ulceration of the cornea provokes the appearance of leukoma, accompanied by a decrease in visual acuity and the appearance of an eyesore. In severe cases, corneal perforation is detected. The development of endophthalmitis in patients with lagophthalmos can lead not only to irreversible visual dysfunction, but also to enucleation.
To confirm the diagnosis, an external examination is performed. The patient is asked to close his eyes (in the usual way and with additional effort) in order to establish the degree of lagophthalmos. A special ophthalmological examination is necessary for early detection of changes on the part of the organ of vision and the choice of further therapeutic tactics. It is carried out by an ophthalmologist and includes:
- Biomicroscopy of the eye. The study reveals the symptoms of damage to the cornea and conjunctiva. When visualizing signs of inflammatory or infectious diseases, surgical treatment is carried out only after their compensation.
- Visometry. Measuring visual acuity is a mandatory diagnostic method, because with severe lagophthalmos, visual dysfunction is often observed.
- Ultrasound in In-mode. The technique is recommended for suspected pan- and endophthalmitis. If a violation of the transparency of the optical media of the eye is detected during biomicroscopy, optical coherence tomography (OCT) is performed instead of ultrasound.
In order to choose an adequate method of treatment, differential diagnosis is carried out between various etiological forms of lagophthalmos. With a paralytic nature, concomitant symptoms are smoothing of the folds on the forehead, lowering of the corner of the mouth. In such cases, additional consultation with a neurologist is required. Anomalies of the eyelid structure are manifested in isolation, usually diagnosed at an early age. Scarring or retraction is preceded by traumatic or inflammatory lesions. A hospital complex of tests for lagophthalmos is prescribed on the eve of surgery.
Drug therapy is aimed at timely moistening of the orbital surface of the organ of vision. The main goal is to prevent the development of xerophthalmia. Patients are shown instillations:
- Antiseptic medications. Regular repetition of the procedure is necessary to prevent infectious and inflammatory complications.
- Moisturizers. Daily use of drugs avoids complications, makes it possible to compensate for the main symptoms in the early stages of development.
- Artificial tear preparations. This group of drugs is used in the development of lagophthalmos against the background of pathology of the trigeminal nerve, which is due to a violation of tear production.
- Anti-inflammatory drugs. The drugs are recommended only in case of diagnosis of infectious or inflammatory diseases (conjunctivitis, keratitis, blepharitis).
Conservative methods of correcting the position of the eyelids are reduced to the use of bandages. The technique is economical and easy to use, but does not provide a long-term effect. The purpose of the operation is to restore the complete closure of the eye slit. The features of surgical treatment are determined by etiology. Reconstructive interventions are used in facial paralysis. Neurolysis allows you to isolate a nerve from the scar tissue that causes its compression. Autotransplantation or reinnervation is possible, in which the distal part of the facial nerve is stitched with the central part of the accessory or sublingual.
Correction of the position and narrowing of the eye slit is provided by tarzo- and blepharography. It is less traumatic to carry out a special thread through the eyelid in a stretched state. The effectiveness of the use of monolithic platinum or gold implants has been proven. If there are contraindications to implantation, levator recession is performed. If lagophthalmos is accompanied by a paralytic eversion, the implementation of canthoplasty is recommended. Palliative treatment is reduced to the injection of hyaluronic acid or botulinum toxin into the upper eyelid area to lower it.
Prognosis and prevention
The prognosis for full-fledged treatment is favorable, since timely surgical correction makes it possible to restore the normal function of the eyelids. In the absence of therapy, inflammatory and degenerative complications may develop in the form of panophthalmitis, corneal perforation and the formation of a cataract. There is no specific prevention of lagophthalmos. Non–specific preventive measures include the exclusion of all potential etiological factors – timely treatment of various infectious and autoimmune diseases, middle ear lesions, etc. To prevent the development of complications, instillations of moisturizers are carried out.