How is coloboma formed?
The eye develops from a protrusion of the wall of the brain bladder, which gradually turns into the optic cup. In the early stages, there is a gap at the bottom of this glass through which the vessels enter; Normally, it closes by the end of the second month of pregnancy. If closure is not completed, a defect remains at the corresponding location. Since the gap is located below and slightly inward, a typical coloboma is directed downward. The causes of the disorder are genetic, including those inherited in the family, and are less often associated with external influences in the first trimester. Often it is not possible to determine a specific cause.
- Incomplete closure of the embryonic fissure of the eye
- The defect is usually directed downward and inward
- May be in one or both eyes
- Genetic causes are common
- May be combined with other developmental defects
Types and how they affect vision
The deeper the affected structure is located, the more vision is affected. Coloboma of the eyelid and iris is noticeable externally, but in itself it reduces vision little: the main complaint is photophobia, since the pupil narrows worse and lets in excess light. Coloboma of the lens is manifested by its unusual shape and is often accompanied by astigmatism. With coloboma of the choroid and retina, part of the visual field is lost, and if the defect involves the central zone or optic nerve, visual acuity decreases significantly. Often there is a combination of several options in one eye.
- Coloboma of the eyelid - defect of the eyelid margin
- Coloboma of the iris - keyhole-shaped pupil
- Coloboma of the lens - changes in shape and astigmatism
- Coloboma of the choroid and retina - loss of visual field
- Coloboma of the optic nerve - severe vision loss
- A combination of several forms is possible
When is it part of the syndrome?
Coloboma sometimes occurs not in isolation, but as part of genetic syndromes in which there are changes in the heart, kidneys, hearing, face and developmental delay. Therefore, a child with such a diagnosis must undergo a general examination by a pediatrician, have his hearing assessed and, if necessary, referred to a geneticist. Parents should tell the doctor if their relatives have similar eye features. It is important to understand: the iris defect itself in an otherwise healthy child is most often isolated and does not mean the presence of the syndrome, but other organs need to be checked.
- Mandatory pediatric examination and developmental assessment
- Hearing test
- Ultrasound of the heart and kidneys as prescribed by a doctor
- Consultation with a geneticist for combined anomalies
- Clarification of family history
Survey
A dilated examination by an ophthalmologist allows you to see all parts of the eye and determine exactly which structures are involved. Autorefractometry reveals myopia, farsightedness and astigmatism, which are common in coloboma and require correction. Ultrasound of the eye is used to evaluate the posterior regions, especially if the examination is hampered by opacities. Older children undergo a visual field test. Observation must be repeated regularly, since with retinal coloboma there is an increased risk of retinal detachment, and the development of amblyopia is also possible - decreased vision due to non-use of the eye.
- Fundus examination with dilated pupil
- Autorefractometry and determination of spectacle correction
- Ultrasound of the eye B-scan
- Computer perimetry in older children
- Monitoring intraocular pressure
- Genetic testing for syndromic forms
What can you do
It is impossible to return the missing tissue, so help is aimed at ensuring that the child uses the available vision as much as possible. The main steps are timely selection of glasses and treatment of amblyopia, including patching the better-seeing eye according to the doctor’s scheme. For severe photophobia, sunglasses, brimmed hats, and, in adolescence, special cosmetic contact lenses with an iris pattern help. Surgical treatment is used for concomitant cataracts, retinal detachment and for aesthetic reasons in adults. Regular examinations and support in studies are important for a child with significant vision loss.
- Selection and constant wearing of glasses
- Treatment of amblyopia, occlusion according to the doctor’s scheme
- Protection from bright light: glasses and hats
- Cosmetic contact lenses optional
- Regular examinations for early detection of retinal detachment
- Surgery for cataracts and complications
- Help in organizing studies for people with low vision
