Children may suffer from similar pathologies to those of adults although some of them are specific and more frequent. We could divide childhood ophthalmologic diseases in congenital ones and acquired ones. – Congenital diseases: Fortunately, eye congenital disorders are uncommon and their seriousness is related to the period in which they may occur. It is not the same that this condition takes place during the eye formation process (before the 12th week of pregnancy) as afterwards, during its development. They can affect any part of the eye but let’s mention the most frequent ones: –Congenital cataracts: Crystalline congenital opacities can be found in any part of it and, depending on their extension and density, their seriousness might vary. Slightly important opacities that barely affect vision mustn’t be treated although they must be surveilled for, some of them, may worsen as time goes by. Very dense opacities, instead, require urgent surgical treatment as the developing of the eye’s visual function completely depends on it. Amongst the most frequent causes of congenital cataracts there are the virosis contracted by mothers-to-be during the first three months of pregnancy, in particular rubella (German measles).

–Palpebral Ptosis: Palpebral ptosis is basically the fact that the upper eyelid position is lower than it should be. It is due to a dysfunction of the eyelid levator muscle which lacks the strength to lift it up. In addition to the unattractive look it causes, it may also lead to a significant functional disorder when it covers the pupil. In this case carrying out a surgical operation will be an emergency as it endangers the child’s normal visual development.

–Congenital lachrymal duct obstruction: About 5% of new-born babies suffer a congenital obstruction of the lachrymal ducts (real tear “drainpipes”). This obstruction can be either unilateral or bilateral. The consequence of the above-mentioned fault is the presentation of continuous epiphora (watering eye) as well as recurrent infections. Most of these cases resolve spontaneously but, when they don’t, we must carry out a duct catheterisation in order to tear the membrane that is causing the obstruction and solve the problem permanently. –Retinal disorders: Some infectious diseases that mothers-to-be may suffer during the firsts months of pregnancy might affect different areas of the eye including the retina. The seriousness of this retinal focus of infection can vary depending on the place it settles. Therefore, it will not be the same that this infection focus is located in the retinal periphery as in the central area where it will endanger vision much more. Amongst the most frequent causes we must underline maternal toxoplasmosis.

–Ocular motility disorders: The absence, the fibrosis or an innervation disorder of an extraocular muscle may cause a congenital condition of the eye motility leading to the apparition of a deviation in some gaze position.

There also exist hereditary conditions amongst which we had better underline retinitis pigmentosa. – Acquired diseases: Children may present the same kind of pathologies as those of adults except for, obviously, age-related ones. Amongst the most frequent ones we can mention: –Refractive defects: This is the most frequent sort of pathology in childhood. From the moment we are born and during the first three years of life some changes occur in the different eye structures which are meant to avoid the existence of any refractive defect. Thus, for instance, the ocular axial length increases from 0,67“ to 0,94”, the cornea flattens and the crystalline modifies its shape and volume. When, doe to any reason, some of these adaptations aren’t fulfilled, the refractive defects arise. Hypermetropy is the most common refractive defect in childhood and must be reckoned physiological when its power doesn’t exceed two dioptres. School age myopia usually begins at the age of 7 (except for degenerative evolutive myopia which may start before) tending to increase up to the age of 18. Astigmatism, generally caused by a corneal deformity, might combine with both previous defects. –Strabismus: The loss of the eyes’ parallelism usually affects around 3% of the population and it starts, before the age of four in 95% of cases. For further details please see the previous chapter in this section. –Allergic conjunctivitis: In spite of the fact that any kind of conjunctivitis (viral, bacterial, etc.) may occur during childhood, allergic ones are the most recurring and those which require a more constant treatment. Often, the participation of an allergologist is necessary to determine their cause.