ADULT STRABISMUS

INTRODUCTION

Strabismus, commonly known as squint eye is a condition in which both eyes do not line up in the same direction. Squint eye is a common condition in children and affects as many as one in twenty children. Strabismus is also called cross eye, wall eye and cast of the eye.

Strabismus, if left untreated can cause amblyopia in children. When the eyes are oriented in different directions, the brain receives 2 different visual images. To avoid double vision, the brain ignores the image formed by the misaligned eye. Due to this the child may suffer from poor vision. Sometimes an eye that has poor vision may develop misalignment.

Strabismus not only causes vision problems, but it can also affects one’s self esteem. . Recent studies show, misaligned eyes can hinder social interaction and emotional happiness.

SYMPTOMS

Common symptoms of strabismus include the following
   Eyes move in different directions
   Blurred or double vision
   Limited perception of depth
   Eyes don’t look in the same direction at the same time

CAUSES

When the eye muscles do not coordinate well with the extraocular muscles, it hampers the binocular vision and causes strabismus. This leads to misaligned eye, which may cause vision problems. Sometimes, strabismus is also caused due to the abnormality of the poorly understood neuromuscular (including brain) control of eye movement. However, the exact cause of strabismus isn’t known. Some are born with it (child strabismus) and some develop it later (strabismus in adults).

Adults may develop strabismus either from a residual childhood strabismus or they may acquire strabismus in adulthood due to other reasons. Other common reasons for adult strabismus are illness or accidents. It also occurs due to injury in the cranial nerves. Strabismus in adults can be caused due to the following reasons:

   Thyroid eye disease
   Stroke or tumors
   Illness
   Accidents

In some cases, the following may cause squint eye:

   Childhood illness
   Genetic conditions- Down's syndrome or cerebral palsy
   hydrocephalus
   Refractive errors

TYPES OF STRABISMUS

There are many different types of strabismus. They are classified into different categories depending on the direction of the eye alignment. Common types of strabismus are esotropia, exotropia, hypotropia, and hypertropia.

Strabismus is also classified depending on its cause. The 3 cranial nerves (III, IV, VI ) responsible for eye movement can be weak or palsied, which causes strabismus. Some examples of paralytic strabismus include third nerve palsy and superior oblique palsy.

Special patterns of strabismus can have unique names, such as Brown syndrome, and Duane syndrome.

Types of Horizontal Strabismus: The term used to describe horizontal strabismus is Esotropia. It is an inward turning of the eyes (aka "crossed eyes"). Types of esotropia include infantile esotropia, accommodative esotropia, and sixth nerve palsy. Exotropia is the term used to describe outward turning of the eyes (aka "wall-eyed")

Types of Vertical Strabismus: The terms hypertropia and hypotropia are used to describe vertical misalignment. Hypertropia is a condition of eye misalignment in which the abnormal eye is higher than the normal eye. On the other hand, hypotropia is used to describe the condition of eye misalignment where the abnormal eye is lower than the normal eye. The terms can generally be interchanged.

TREATMENT

The goal of strabismus treatment is to improve eye alignment, which will help the eyes to work well together (binocular vision). Treatment involves- eye glasses, eye exercises, prism, and/ or eye muscle surgery. Problems associated with strabismus (including amblyopia, ptosis, and cataract) are usually treated prior to eye muscle surgery.

Most adults with misaligned eyes often experience good results from successful surgical correction, such as eye muscle surgery.

FAQ ON EYE MUSCLE SURGERY

Is eye muscle surgery risky for adults?

Every surgical procedure involves some possible risks. With eye muscle surgery, the residual misalignment of the eyes and double vision are the most usual risks. Most double vision that occurs after strabismus surgery is temporary; however, persistent double vision is possible. This surgery involves a few critical risks. These risks are critical but rare, they include- anesthetic complications, infection, bleeding, retinal detachment, and decreased vision. Surgery risks depend on the overall health of an individual and vary accordingly. Surgery under local anesthesia instead of general anesthesia should be considered for patients with poor health.

How successful is eye muscle surgery?

Often, patients notice and feel a significant improvement in eye alignment after the first surgery. Occasionally there is a need for an additional surgery for the correction of residual double vision.

How painful is this type of surgery?

The surgery involves a few discomforts, but is not painful. Headache, pulling sensation with eye movement and foreign body sensation in the eye are the most common complaints. These discomforts are temporary, and reduce after a period of time. Over-the-counter pain medications can be used to find some relief. Most patients return to full activity in few weeks. Some surgeons limit swimming and heavy physical activity for a longer period of time after surgery.

What age is considered "too old" to have eye muscle surgery?

Eye straightening can be performed at any age. One should consider this treatment to improve the quality of their vision.

Is eye straightening as an adult strictly cosmetic?

No. Eye alignment surgery need not be strictly cosmetic. They can be performed for various reasons, such as to improve the double vision and the depth perception. They are performed to improve the health of the eye and also the quality of living.