Pathology in children squint (strabismus)
Strabismus measurement involves many steps and is very important because it has a decisive influence on the diagnosis, treatment, and prognosis.
Strabismus is a fairly common childhood disease in which there is a change in the marks of one or both eyes. The strabismus may deviate inward or outward (transverse strabismus), upward or downward (transverse strabismus), or combined strabismus (transverse strabismus). Strabismus is usually evident when both eyes are looking straight ahead. If the eye is not crossed, the crossed eye will move to bring the eye back to the straight look.
Strabismus measurement involves many steps and is very important because it has a decisive influence on the diagnosis, treatment, and prognosis. The basic requirements of the strabismus examination include the history of strabismus, visual acuity, refraction, strabismus measurement, ophthalmology, and binocular vision. When taking history, some points are noted such as age at the appearance of strabismus, birth abnormalities, nature of strabismus (frequently, intermittently, strabismus in one or both eyes). Visual acuity examination in children is often difficult and may require specific methods of detecting strabismus-induced amblyopia (amblyopia) on which to base decisions on amblyopia training or surgery. Refractive examination is always required with an accommodation palsy to help differentiate between accommodation and non-accommodation strabismus. Determining the correct refraction and correcting the lenses is an important part of the treatment process.
Strabismus measurement indicates strabismus morphology and degree of strabismus. There are many methods of measuring strabismus. The simplest is the Hirschberg method (using a light source shining directly in front of the eye, about 40 cm from the eye, and observing the reflection in the center of the pupillary. If the eye is crossed inward, the reflection is deflected outward, if the eye is crossed outward, then the reflector is deflected inward. For every 1mm deviation of the reflective dot, it corresponds to 7-8 degrees of strabismus, the reflective dot is deviated to the border of the pupillary, corresponding to strabission, by 15 degrees, and to the edge of the cornea, corresponding to strabission of 45 degrees. ). For more precise measurements of strabismus, prisms, the Krimsky method (eye-shading prisms), or synoptophore measurements can be used. The ocular motor examination helps to distinguish strabismus from functional strabismus and strabismus motor abnormalities (hyperactivity, hypoactivity). Binocular vision examination to detect abnormal visual adaptations due to strabismus requires preoperative binocular rehabilitation training.
Congenital inward strabismus is the most common form (accounting for about 40% of all strabismus forms). The strabismus can be monocular (indicating amblyopia) or alternately if the visual acuity is similar. The most common forms of inward strabismus are idiopathic inward strabismus (appears very early, refractive error is negligible, strabismus is usually stable), accommodation strabismus due to refractive error (strabismus appears later, often have high farsightedness, strabismus often when the patient looks at close objects), and astigmatism strabismus not due to refractive error (negligible refractive error associated with abnormality of the accommodation to accommodation ratio [ AC/A]).
The incidence of outward strabismus is much less than that of inward strabismus. The two common forms of outward strabismus are frequent strabismus and intermittent outward strabismus. Frequent outward strabismus often appears early, high strabismus, stable refraction, may be accompanied by physical damage (especially cataracts, corneal disease, damage to the retina and optic nerve). Intermittent outward strabismus often appears later, less amblyopia).
Some special strabismus forms
Duane's syndrome: strabismus (inward or outward), possibly non-strabismus, with narrowing of the ciliary slit when the eye is brought in, limited ocular movement inward or outward.
Brown's syndrome: eyes limited inward and upward, ocular movements in other directions are normal, eyes are not crossed or crossed downwards. This syndrome can be congenital or acquired, resulting from damage to the large oblique muscle or muscle pulley.
Mobius syndrome: strabismus caused by paralysis of nerves VI, VII. Inner strabismus with large strabismus, eyes cannot gaze out, accompanied by atrophy of the tip of the tongue (XIII nerve palsy).
Paralysis of the muscles that lift the eyes up: The paralyzed eye is usually strabismus lower and cannot glance in the upward direction.
Congenital great oblique muscle paralysis: strabismus upward, accompanied by a tilt of the head to the good eye and a lower chin.
Letter syndrome (A or V): in the letter A syndrome, in the inner strabismus, the strabismus increases when the eyes look up and decrease when the eyes look down. In the strabismus, the strabismus increases when the eyes look down and decrease when the eyes look down and lookup. The V syndrome is the opposite of the A syndrome.