Anophthalmos is an ophthalmopathology characterized by the absence of an eyeball in the orbit. Clinical manifestations of the disease are irreversible loss of visual functions on the side of the lesion, narrowing of the boundaries of the visual field, violation of spatial perception and rapid fatigue when performing visual work with a healthy eye. Diagnostics includes external examination, biomicroscopy of the eye, ultrasound and pathomorphological examination. The specific treatment is based on step-by-step prosthetics. Additionally, instillations of antiseptic agents are shown. Surgical correction of cosmetic defects is carried out according to individual indications.
Q11.1 Other type of anophthalmos
Anophthalmos is a common ophthalmopathology. According to statistics, the prevalence of the congenital form is 1-2.1 per 10 thousand population. In adulthood, this indicator ranges from 21 to 22.3 per 10 thousand, since about 12,000 enucleations are performed on patients during each year. In children, the disease is diagnosed in 0.4% of cases. Removal of the eyeball is a forced measure in 5-12% of patients with a history of severe eye injury.
Causes of anophthalmos
Anophthalmos is classified as a polyethological disease. The triggering factor of the development of the congenital form in most cases cannot be precisely determined. The main causes of congenital and acquired forms of pathology are considered to be:
- Intrauterine infections. Anophthalmic syndrome may be a consequence of the action of measles, rubella or herpes zoster viruses at the stage of embryogenesis.
- Amniotic cords. Amniotic constriction syndrome is the cause of multiple pathologies of the visual organ. Depending on the gestation period at which they were formed, anophthalmos develops or milder forms of eye damage (hypertelorism, strabismus, microphthalmos).
- Genetic syndromes. Anophthalmos often occurs in combination with multiple developmental abnormalities on the background of chromosomal pathologies (Patau, Lenz, Lohmann syndromes) or mutations of the PAX6, SOX2, OTX2 and VSX2 genes.
- The effect of teratogenic factors. Ionizing radiation, the use of alcoholic beverages, certain pharmacological preparations, and narcotic drugs have a teratogenic effect on the organ of vision.
- Traumatic injuries. Domestic or industrial injuries can lead to the development of anophthalmos. Enucleation is resorted to due to the occurrence of post-traumatic atrophy, chronic uveitis or a high risk of attachment of sympathetic ophthalmia.
- Oncological diseases. Removal of the eyeball can be performed in the presence of a malignant tumor.
Congenital malformation of the eyeball occurs under the action of teratogenic factors at 2-6 weeks of embryogenesis. During this period of time, the process of laying the organ of vision is disrupted. With a defect in the structure of the rudiments, the process of formation of the eye bladder and its further transition into the eye glass is impossible. If the influence of pathogenic factors occurs at the time of the already formed eyeglass, then its low-differentiated rudiment can be detected in the orbital cavity. Anophthalmos may be an early manifestation of a genetic syndrome caused by a gene or chromosomal mutation. Acquired pathology develops as a result of massive damage or surgical removal of the eyeball.
According to the time of occurrence, anophthalmos is classified into congenital and acquired. A one- and two-sided option is possible. This type of systematization is used at the stage of diagnosis. From a clinical point of view , the following forms of pathology are distinguished in practical ophthalmology:
- True. The disease is combined with the absence of the external cranial body, chiasm, optic nerve and its canal. The true type is exclusively congenital and often occurs simultaneously with other malformations.
- Imaginary. The complete absence of an eye is revealed. Other structures of the orbit are characterized by a normal anatomical and physiological structure. Radiographic diagnostic methods allow visualizing the optic nerve channel.
Symptoms of anophthalmos
Anophthalmos is manifested by irreversible loss of visual functions. In the unilateral form of the disease, the visual acuity of the other eye may correspond to the norm. The loss of binocular vision leads to a narrowing of the boundaries of visual fields, a violation of spatial perception. Patients present asthenopic complaints associated with rapid fatigue of the accommodation apparatus. Adaptation to monocular deep vision is better at a young age. During enucleation due to blindness, adaptation occurs as visual dysfunction progresses. The combination of anophthalmos with damage to the nervous system leads to severe soreness in the projection area of the eye socket with irradiation to the back of the head.
The lack of timely step-by-step prosthetics in the congenital form of anophthalmos leads to facial asymmetry. On the side of the lesion, there is a lowering of the eyebrow, lifting of the wing of the nose and the corner of the mouth. As the child grows, the severity of the deformity increases, which entails a violation of the function of breathing and the act of chewing. The presence of a rudimentary eyeball in the cavity of the orbit of a low degree of differentiation is often the reason for the addition of complications of an infectious and inflammatory nature. In some cases, a retrobulbar abscess or phlegmon of the orbit develops.
Visually, the absence of an eye in the orbit cavity is determined. The shape of the conjunctival cavity is close to conical, reduced in size. The narrowing of the ocular slit is combined with an internal epicanthus, entropion, or the complete absence of a fold of the upper eyelid. Instrumental diagnostics includes:
- Biomicroscopy of the eye. The study reveals the disproportion of the conjunctival arches, a narrowed eye slit, an incorrect position of the eyelids, multiple scars and adhesions.
- CT scan of the brain. CT is used for differential diagnosis between the imaginary and true form of anophthalmos and microphthalmos. In an imaginary form, the optic nerve channel is visualized. A distinctive feature of microphthalmos is the presence of a low–differentiated rudiment in the orbital cavity.
- Ultrasound of the eyes. The use of the technique is recommended for assessing the state of the orbital cavity, determining the echogenicity of the contents of the orbit.
- Pathomorphological research. The method allows the ophthalmologist to determine the degree of reduction of the eye and its correlation with the stage of embryogenesis.
All patients with a congenital form of the disease are advised to consult a geneticist, since anophthalmos can act as an early manifestation of genetic pathology. The addition of neurological symptoms, soreness and asymmetry of the face require examination by a neurologist.
Treatment of anophthalmos
It is impossible to restore visual acuity with anophthalmos. The purpose of treatment is to eliminate the cosmetic defect and prevent complications. Surgical tactics are reduced to step-by-step prosthetics, which must be performed in early childhood with gradual replacement with a larger diameter prosthesis. Eye prosthetics is performed in several stages:
- Preparation. Radical intervention is shown – enucleation or removal of the rudiment of the eyeglass. If there is a pronounced defect in the walls of the eye socket, their surgical plastic surgery is performed.
- Individual prosthetics. Development of a prosthesis taking into account the color and relief characteristics suitable for the patient.
Conservative therapy for anophthalmos is reduced to daily instillation of antiseptic solutions. With pronounced defects of the eyelids, surgical correction of lagophthalmos, entropion is performed. The implementation of cantotomy is justified only after the patient reaches the age of 18, since earlier intervention is complicated by entropion.
Prognosis and prevention
The principle of step-by-step prosthetics in the treatment of patients with anophthalmos makes it possible to eliminate cosmetic defects and prevent the formation of bone deformities of the facial part of the skull. It is impossible to restore visual functions in this pathology, but the disease does not pose a threat to the patient’s life. No specific preventive measures have been developed. Non-specific prevention of the acquired form is reduced to compliance with safety regulations at work and at home. To reduce the risk of developing congenital anophthalmos, the teratogenic effect of various factors should be avoided from the 2nd to the 6th week of pregnancy.