Child development is directly related to visual development. This means that some ophthalmologic alterations can affect or create a difficulty in the child’s learning.
Visual development begins at birth and ends between 7 and 9 years of age, and for it to be completed correctly it is necessary that no ophthalmologic alteration occurs during this period. In order for the child to have a correct visual capacity, both in quantity (visual acuity) and quality (binocular vision/stereopsis), early diagnosis of any ocular disease is necessary.
A delay in the diagnosis of ophthalmologic pathologies can cause a lifelong defect. Therefore, periodic check-ups with an ophthalmology specialist are recommended, who will use the appropriate means for each age. If no alterations are observed, these ophthalmologic examinations will begin when the child is 2-3 years old, regardless of whether or not there is a family history, and thereafter they will be done annually. The child’s visual system changes as he/she grows.
Visual development: when does it occur and what should the child see at each age?
Visual development begins at birth, which is when the retina begins to receive stimuli.
The child does not follow objects until he/she is two months old, and it may take longer if he/she is a child who sleeps many hours. Normally at 6 months there should already be a coordinated and correct eye movement. Between 3 and 5 years of age, the child will have maximum visual acuity, and between 7 and 9 years of age, visual development is complete.
What are the most common ophthalmologic pathologies in childhood?
In order of frequency, the most common ophthalmologic pathologies are:
- Refractive defects: hyperopia, astigmatism and myopia.
- Amblyopia or lazy eye.
There are other pathologies that are serious but, fortunately, rare:
- Retinopathy of prematurity.
- Congenital glaucoma.
- Congenital cataracts.
- Retinoblastoma or retinal tumor and retinal lesions.
- Palpebral ptosis.
- Corneal alterations.
There are also other diseases that, despite being very common, do not involve any alteration in visual development, but it is also important to diagnose them correctly and treat them:
- Allergic conjunctivitis.
- Congenital lacrimal obstruction.
What are refractive defects and how do they affect a child’s vision?
Refractive defects (myopia, astigmatism and hyperopia) occur in 20% of the child and adolescent population. In fact, they are the second cause of amblyopia (lazy eye), after strabismus, and a major cause of school failure. That is why regular ophthalmological check-ups are very important, which should include a study with pharmacological mydriasis (dilation of the pupil with drops), carried out by an ophthalmologist.
What is lazy eye and how can it affect visual acuity?
Amblyopia is considered amblyopia when there is a visual deficit as a consequence of an alteration in visual development. Usually lazy eye affects only one eye, i.e. it is monocular, and affects 2-5% of the population, and up to 50% of children with strabismus will suffer from amblyopia or lazy eye.
Lazy eye can appear in the differences of graduation between both eyes (anisometropia), in cases of strabismus or if the child has an organic lesion (corneal opacity, eyelid ptosis or cataracts).
Treatment consists of addressing the cause, first of all, as well as correcting the refractive defect if it exists (20% of the population with lazy eye), optical correction (glasses) and stimulating the lazy eye by covering the child’s healthy eye with a patch. Early treatment will be effective and the patient will be able to recover 100% visual acuity.
The recovery of the lazy eye will depend on the age at which visual development is interrupted, the age at which treatment is started and the time that elapses between the two, as well as the severity of the visual deficit and whether the treatment is carried out correctly. In any case, it is very important a good prevention, making revisions with the specialist in Ophthalmology in all ages.
Why does strabismus occur?
Strabismus is a disease that affects children, although it can also occur in adulthood, in which there is a loss of parallelism of both eyes in any gaze position. This means that one eye is deviated. It affects 4% of the child population.
Sometimes there may be a feeling that the child has a deviated eye and suffers from strabismus, but in reality there is no strabismus, and it is a pseudostrabismus or false strabismus, which is given by the shape of the eyelids and nose. This can be seen in cases of epicantus, hypertelorism, hypotelorism or telecanthus.
There are different types of strabismus, and each may require different treatments (occlusions, optical corrections or surgery). In some cases, several surgeries may be necessary to correct the deviation.