What Is Anophthalmia?
Anophthalmia is a condition wherein a baby may be born without an eye. This could be present in one or both eyes. Anophthalmia is a serious type of eye malformation characterized by the complete absence of the eye. This varies from a similar condition, microphthalmia, in which the patient has remnants of formative eye tissues in the eye socket. Of note, the expression "clinical anophthalmia" may denote the complete absence of the eye, but there is some remaining tissue. Anophthalmia may occur individually or as a part of other syndromes.
What Are the Types of Anophthalmia?
Based on the condition, its severity, and the remaining tissue, anophthalmia can be classified as:
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True Anophthalmia: The eye tissue is absent.
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Extreme Anophthalmia: In place of the eye, a small amount of tissue can be present.
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Clinical Anophthalmia: This condition is in between true and extreme anophthalmia.
Based on the causative factor, anophthalmia can be classified as:
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Primary Anophthalmia: It is optic pit failure wherein eye formation is absent.
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Secondary Anophthalmia: This is a neural tube defect wherein the eye formation begins but stops due to the defect.
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Degenerative Anophthalmia: The formation usually happens but may undergo degeneration.
What Causes Anophthalmia?
Anophthalmia has multiple causative factors that are not entirely known yet. It may be caused due to both genetic as well as environmental causes.
Environmental Causes of Anophthalmia:
The environmental factors can include:
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Anophthalmia can be caused due to TORCH diseases, including CMV (cytomegalovirus), rubella, Parvovirus B19, and toxoplasmosis,
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Deficiency of vitamins such as vitamin A.
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Fetal exposure to harmful chemicals such as liquor, thalidomide, and warfarin.
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Anophthalmia can also be caused due to failure of the optic disc, such as failure of neural tube formation or break of the optic disc.
Genetic Causes Causes of Anophthalmia:
The genetic causes can include:
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Anophthalmia can be caused due to genetic mutations. This mutation can occur in a single gene or the entire chromosome.
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A whole chromosome might be missing or might be copied or may go through movement, where a section of a chromosome is moved to an alternate chromosome. This is known as the translocation of the gene. This translocation of the genes can also lead to conditions such as cataracts, glaucoma, and neural tube defects.
What Are the Risk Factors of Anophthalmia?
Certain conditions increase the risk of developing anophthalmia which include:
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Maternal age is more than 40 years.
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Multiple pregnancies.
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Low birth weight.
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Unexpected labor.
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Radiation exposure, including X-ray beams during pregnancy
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Impact of specific synthetic substances, medications, pesticides, or liquor during pregnancy. Medications such as thalidomide and warfarin have been involved
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Certain viral contaminants during pregnancy like German measles, toxoplasmosis, varicella, and cytomegalovirus.
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Nutritional deficiencies of the mother.
What Are the Signs and Symptoms Of Anophthalmia?
Anophthalmia presents as an empty eye socket during the pregnancy. The eye attachment might be more modest in size. The tear glands and eye muscles are normally missing. A child with anophthalmia may develop facial asymmetry if this condition is not addressed immediately. If anophthalmia occurs with other symptoms, it may affect other organs also. It may cause defects in the lungs and heart.
How Is Anophthalmia Diagnosed?
The diagnosis of anophthalmia can be made in the following ways,
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Pre-birth Assessment: Anophthalmia can be found prenatally in view of the perception of orbital designs through ultrasound. Visual mutations can be distinguished as soon as the completion of the first trimester by utilization of two, and three-layered ultrasounds, and analysis can be rechecked with fetal MRI (magnetic resonance imaging). However, anophthalmia is only occasionally diagnosed by pre-birth ultrasound except if present with other irregularities. Given the possible occurrence of syndromic etiology of anophthalmia, amniocentesis should be performed to check for other possible malformations. Other examinations, such as vitamin deficiencies of the mother, should also be checked.
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Post-pregnancy Assessment: Neonatal highlights of anophthalmia include top-down designs with a narrow cover gap and a small conjunctival sac. A thorough assessment should be designed to identify any other anomalies that would suggest the presence of a hereditary illness. One-sided anophthalmia can cause ophthalmic findings in the single eye, such as coloboma, retinal abnormalities, or optic nerve hypoplasia. Any suspicion of visual distortion should prompt a pediatric ophthalmologist's assessment as soon as time permits. This assessment should include a detailed analysis of the shapes of the eyes and circles and a review of the parents to check for any significant family ties, gestational openness, or visual anomalies.
Imaging:
An ultrasound should be done to check for the presence of optic structures if an ocular abnormality is suspected. If functional retinal tissue is still present, electrodiagnostic such as flash visual evoked potentials can be employed to identify it. Further defining the contents of the globe, the level of central optic nerve tissue involvement, and screening for concurrent CNS (central nervous system) abnormalities are all possible with CT (computed tomography) and MRI imaging. Contrasts an MRI of a patient with anophthalmia and a patient with normal optic structures within the socket. Pituitary hypoplasia, hippocampal malformation, hypothalamic abnormalities, and deficiencies in the fusiform gyrus are among the CNS abnormalities that may be present in syndromic anophthalmia. Due to the substantial co-occurrence of ocular and renal problems in patients with anophthalmia, renal ultrasonography is also advised.
How Is Anophthalmia Treated?
Anophthalmia makes it impossible to recover vision in the missing eye. However, employing a prosthetic device can enhance the cosmetic result. Since conformers need to be changed regularly, they are used up to about the age of two. Contrary to prosthetic eyes, conformers are not painted. Instead of conformers, expanders that inflate are an option. Conformers are replaced with prosthetic eyes that are painted to resemble the natural eye after two years of age. The prosthetic eye encourages the growth of the socket in a similar way to conformers. Additionally, it will need to be updated a few times as the face grows during the growing years. Unfortunately, because the eye prosthesis is immobile, a real-looking eye is impossible.
Conclusion:
Anophthalmia is a condition wherein there is a missing eye or eyes. This may occur as a single condition or as a group of symptoms. At times it can be diagnosed before birth itself. Care should be taken during pregnancy to avoid nutritional deficiencies. An early diagnosis can help to treat this condition more effectively.
