Major visual impairments in childhood

Astigmatism is a refractive error that causes blurred and distorted vision, both near and far vision, and that manifests itself when images are focused on several points on the retina. In contrast, in emmetropic (non-prescription) eyes, images focus on a single point on the retina.

People who suffer from astigmatism are characterized by alterations in their corneal curvature, that is, their cornea has an irregular curvature, instead of being symmetrical.

This visual anomaly does not always occur in isolation, as it is often associated with myopia or hyperopia.

Like nearsightedness and farsightedness, astigmatism can be genetically determined. It may also occur after trauma, injury, or illness, or as a consequence of eye surgery.

Astigmatism is the third most common visual problem among Spaniards (behind myopia and presbyopia or eyestrain), since more than a quarter of the population suffers from it.

The main symptom of astigmatism is blurred and distorted vision of near and distant objects, as well as difficulty perceiving small details at all distances.

When astigmatism is associated with hyperopia, it is common for the patient to present symptoms such as visual fatigue, redness, itching and stinging of the eyes, dizziness or occasional headache, due to the overexertion made by the eye to focus on images.

The symptoms that the patient may perceive are different depending on their age, type of astigmatism or prescription. However, in mild cases it is possible to miss any signs of astigmatism.

Congenital cataract is one that the child suffers from at the time of birth, which can make it difficult or seriously compromise their vision depending on the degree of opacity of their lens.

Usually, aging is the main cause of cataract formation since, over the years, the lens becomes opaque. However, it is possible for a child to also have this pathology at birth.

Unlike adults, this type of cataract is not diagnosed by alterations in vision, but is evidenced by a visible whitish or grayish spot in the pupil. Other symptoms of congenital cataract that can be seen in the child as a result of poor vision are the involuntary and rapid movement of their eyes (nystagmus) or eye deviation (strabismus).

When it comes to a mild congenital cataract, these symptoms may not manifest clearly enough. Hence the importance of subjecting the child to a first ophthalmological examination after birth in order to rule it out, as well as other congenital vision anomalies.

Its presence (in one or both eyes) is a rare situation that is usually associated with hereditary factors, although there may be other causes such as associated eye pathologies or genetic conditions.

Conjunctivitis is inflammation of the conjunctiva, a clear membrane that lines the sclera (white part of the eye) and contains small blood vessels. When these vessels become inflamed, the eye becomes red. It can appear in adults and children and usually evolves favorably, unless it is not treated properly.

Conjunctivitis can be caused by a bacterial or viral infection, an allergic reaction due to exposure to an agent (allergens) that induces hypersensitivity in some people, or irritation of the edge of the eyelid (blepharitis) as a result of the use of cosmetics or contact with irritating substances in the environment. Each of these causes gives rise to different types of conjunctivitis: infectious conjunctivitis, allergic conjunctivitis, irritative conjunctivitis.

The symptoms of conjunctivitis are very visible and characteristic, such as eye redness, itching (predominant in allergic conjunctivitis), tearing, secretions and stuck eyelids (especially in bacterial conjunctivitis). To a lesser extent, when conjunctivitis occurs with complications, it can produce a foreign body sensation inside the eye, greater sensitivity to light and significant inflammation of the eyelids.

It is a chromatic vision disorder that is genetically transmitted (it is linked to the X chromosome) and consists of difficulty distinguishing certain colors. This dysfunction is associated with the cones, a type of photoreceptor cell in the human eye, responsible for detecting color, and which are located in the most superficial layer of the retina.

Color blindness is more prevalent in males (8% in boys and 0.5% in girls). The classic form of color blindness is the alteration between red and green, although there are different degrees of color blindness. Color blindness has no treatment, but it is important to detect it in the case of children, as it can influence their personal development, as well as their learning process.

It is a visual defect that consists of the deviation of one or both eyes in one of the positions of the gaze, as a result of the lack of coordination between the eye muscles. This causes the loss of parallelism between the two eyes and incorrect binocular vision , affecting the ability to see in relief, calculate distances and see in 3D.

Small intermittent deviations may appear before 6 months, without necessarily being associated with any problems. This functional strabismus of newborns is known as congenital strabismus. However, you should visit the ophthalmologist when it is a permanent deviation. It should be borne in mind that, if strabismus is not corrected early, that is, before the age of 7-8 approximately, the decrease in vision in the deviated eye can become permanent and irreversible.

Amblyopia or lazy eye is the most serious consequence of strabismus and the most frequent cause of unilateral visual loss (vision in only one eye) in children and young people. The child who suffers from lazy eye uses one eye less than the other, which becomes “lazy”.

Strabismus can be classified according to different criteria such as the direction of deviation (convergent, divergent and vertical), persistence over time (temporary and permanent) and the dominance or not of one eye. In this case, strabismus can occur alternately, that is, sometimes the child looks with one eye (dominant eye) and deviates the other, and other times, it does it the other way around. The dominant eye can alternate or always be the same.

The origin of strabismus is mainly related to alterations in the functioning of the eye muscles, differences in vision between the two eyes due to associated refractive errors and trauma that exerts pressure on the eye.

Farsightedness is a refractive error that causes blurred and uncomfortable vision of nearby objects (and sometimes also distant objects). Unlike myopia, the images are focused behind the retina and not directly on it.

People who suffer from hyperopia are characterised by alterations in the different structures of the eye such as its corneal curvature, the optical power of its lens (low power) or the size of its eyeball (shorter than normal length).

Like myopia, farsightedness has an important hereditary component.

The main symptom of farsightedness is poor near vision. If the hyperopia is low, the patient will see well at a distance, although their effort to focus or accommodate will be greater. This can lead to other symptoms such as headache and eye strain.

In many cases, its effects are not noticed until, from the age of 40, the ability to accommodate is reduced.

Myopia is a refractive error that manifests itself when distant objects are projected at a point in front of the retina, instead of on it. As a result, a distorted perception of the image occurs and, therefore, vision is blurred and poorly defined.

People who suffer from myopia are characterised by alterations in the different structures of the eye such as its corneal curvature, the optical power of its lens (excessive power) or the size of its eyeball (excessive length).

Myopia is the most common visual defect among people under the age of 45 and can be associated with other refractive errors, such as astigmatism (myopic astigmatism) and presbyopia or eyestrain.

The main symptom of the patient with myopia is that they have poor distance vision and yet optimal near vision. Other symptoms you may suffer from are eye strain, headache, difficulty concentrating, permanent dry/itchy eyes, etc.

Symptoms of myopia can appear from an early age. For this reason, it is advisable to have a complete ophthalmologic examination from the age of 3-4 years to detect or rule out any visual alteration that is still latent. If there is a family history or if there are any previous symptoms, it is recommended to perform this examination before this age.

Eyelid ptosis is the drooping of the upper eyelid that partially or completely covers the eye. This alteration of their normal position can affect the visual field, seriously interfering with the patient’s vision. When it occurs before the age of 8 it is called infantile eyelid ptosis.

This type of eyelid malposition in children occurs from birth, because it is usually of congenital origin and is usually related to poor development of the muscle that is responsible for raising the eyelid. On the contrary, in adults it is usually acquired by multiple causes (age, trauma, functional problems of the muscle, etc.).

There are unmistakable signs in children suffering from eyelid ptosis, such as tilting their head back to see better or even lifting their eyelid with their fingers. In general, there is difficulty in keeping their eyes open when they perform daily activities such as reading, writing, drawing, etc.