Vertical strabismus

If you feel that the other person cannot look you in the eye when you are talking to him/her, and if you feel that he/she is looking at someone else even though he/she is clearly looking at you, this is strabismus. There are many types of strabismus, including esotropia, exotropia, and vertical strabismus. If a child has strabismus, it can be treated through minimally invasive surgery with a very high success rate. If the best time for treatment is delayed, it is likely to affect the child's self-confidence and appearance in adulthood.

Strabismus is a particularly serious disease at present. The occurrence of this disease brings a lot of harm, especially to some children, which will cause their eyes to be abnormal and often be ridiculed by others. What are the main symptoms of strabismus? Next, I will introduce to you what the symptoms of this disease are.

Strabismus refers to the inability of both eyes to focus on the target at the same time, which is a disease of the extraocular muscles. It can be divided into two categories: concomitant strabismus and paralytic strabismus. The main clinical features of the former are eye deviation to the temporal side, no eye movement disorder, and no diplopia; while paralytic strabismus has restricted eye movement, diplopia, and systemic symptoms such as dizziness, nausea, and unstable gait. The causes of strabismus are complex. Modern Western medicine has no ideal method for those with unknown causes, except for treating the causes and providing surgical treatment.

Clinically, the separation of binocular visual axes caused by abnormal eye position or movement is called strabismus, which is a common type of ophthalmological disease. Strabismus can be divided into two categories: co-rotational strabismus and non-co-rotational strabismus, depending on whether the patient has extraocular muscle dysfunction. Co-rotational strabismus, also known as common strabismus, is a condition in which the extraocular muscles function normally, the eyeballs can move in all directions without obstruction, but the visual axes of the two eyes are separated. According to the nature of the fixating eye, it can be divided into unilateral and binocular alternating; according to the time of occurrence of strabismus, it can be divided into intermittent, constant or periodic.

Non-corotational strabismus, also known as paralytic strabismus, is a condition in which the visual axes of both eyes are separated due to paralysis of one or several extraocular muscles caused by dysfunction of nerve conduction or the extraocular muscles themselves. The affected eye will inevitably have movement disorders in one or more directions due to paralysis of the eye muscles. After determining whether the strabismus patient has corotational or non-corotational strabismus, corotational strabismus can be divided into esotropia, exotropia and vertical strabismus according to the direction of eye deviation. Paralytic strabismus is named according to the paralyzed nerve or dysfunctional extraocular muscle, such as oculomotor nerve paralysis, superior oblique muscle paralysis, etc. Since there are many extraocular muscles that control eye movement and multiple eye muscles are involved in the coordinated movement of binocular vision, the mechanism of strabismus is relatively complicated. To understand strabismus, we must first clarify the mechanism of coordinated movement of binocular eye muscles and binocular single vision.

Humans have six extraocular muscles in each eye that control eye movement, including four rectus muscles and two oblique muscles. According to their attachment positions on the eyeball, they are called the medial rectus muscle, lateral rectus muscle, superior rectus muscle, inferior rectus muscle, superior oblique muscle and inferior oblique muscle. Among them, the function of the internal and external rectus muscles is relatively simple, and they control the horizontal movement of the eyeball. Because the attachment points of the superior and inferior rectus muscles and the superior and inferior oblique muscles are deviated from the vertical direction of the eyeball, their functions are more complex. In addition to coordinating the vertical movement of the eyeball, they also have the function of causing the eyeball to rotate inward and outward, thereby allowing the eyeball to focus in all directions in front.

Under normal circumstances, binocular movements must be coordinated so that both eyes can focus on a single target at the same time. This function requires the coordinated movement of the extraocular muscles of both eyes. The coordinated movement of the extraocular muscles when viewing objects with both eyes is a complex muscle coordination movement. Take the horizontal movement of both eyes as an example: when looking to the right, the right lateral rectus muscle and the left medial rectus muscle contract, while the right medial rectus muscle and the left lateral rectus muscle relax to make both eyes rotate to the right, and the rotation angles must remain equal. The superior and inferior rectus muscles and the superior and inferior oblique muscles must also have a certain degree of tension to assist in eye movement and maintain a horizontal position of the eye. In this process, the pair of eye muscles (right lateral rectus muscle and left medial rectus muscle) that play a pulling role in the direction of eye movement are called spouse muscles, while the pair of eye muscles (right medial rectus muscle and left lateral rectus muscle) that play a main antagonistic role with this pair of muscles are called antagonistic muscles.

When the eyeball moves vertically, since multiple groups of extraocular muscles are involved in the movement, there are not only spouse muscles, but also synergistic muscles to assist in the direction of movement. There are also direct antagonistic muscles and indirect antagonistic muscles in the opposite direction, making the coordinated movement more complicated. The partner and antagonist muscles of eye movements in each direction. The coordinated movement of the extraocular muscles of both eyes follows two laws: one is that the contraction of one extraocular muscle must be accompanied by the relaxation of its direct antagonistic muscle, otherwise the eyeball cannot rotate flexibly. This law is called Sherrington's law. The second is that the nerve impulses from the central nervous system that cause the eyeballs to rotate must reach both eyes simultaneously and equally, otherwise the two eyes cannot focus on the same target. This law is called Hering's law. These regularities of eye movement form the basis for human binocular single vision.

After reading the above knowledge, you should have a clear understanding of the symptoms of strabismus. The occurrence of strabismus has a lot of impact on patients. We need to pay attention to the disease of strabismus, and after discovering that the child has the above-mentioned related symptoms, we need to treat it as soon as possible.