Strabismus Causes

Six eye muscles, controlling eye movement, are attached to the outside of each eye. In each eye, one muscle moves in the eye to the right, and one muscle moves the eye to the left.

To line up and focus both eyes on a single target, all of the muscles in each eye must be balanced and working together. In order for the eyes to move together, the muscles in both eyes must be coordinated. The brain controls these muscles.

With normal vision, both eyes aim at the same spot. The brain then combines the two pictures into a single, three-dimensional image. This three-dimensional image gives us depth perception.

When one eye is out of alignment, two different pictures are sent to the brain. In a young child, the brain learns to ignore the image of the misaligned eye and sees only the image from the straight or better-seeing eye. The child then loses depth perception.

Adults who develop strabismus often have double vision because their brains have already learned to receive images from both eyes and cannot ignore the image from the turned eye. A child generally does not see double.

Strabismus is especially common among children with disorders that may affect the brain, such as:
Cerebral palsy;
Down syndrome;
Hydrocephalus;
Brain tumors;
Prematurity.

A cataract or eye injury that affect vision can also cause strabismus. The vast majority of children with strabismus, however, have none of these problems. Many do have a family history of strabismus.

Strabismic amblyopia

Good vision develops during childhood when both eyes have normal alignment. Strabismus may cause reduces vision, or amblyopia, in the misaligned eye.

The brain will pay attention to the image of the straight eye and ignore the image of the crossed eye. If the same eye is consistently ignored during early childhood, the misaligned eye may fail to develop good vision, or may even lose vision. Strabismic amblyopia occurs in approximately half of the children who have strabismus.

Amblyopia can be treated by patching or blurring the stronger eye to strengthen and improve vision in the weaker eye. If amblyopia is detected in the first few years of life, treatment is usually successful. If treatment is delayed, amblyopia may become permanent. As a rule, the earlier amblyopia is treated, the better the result for vision.

Strabismus Diagnosis

Strabismus can be diagnosed during an eye exam. It is recommended that all children between 3 and 3 1/2 years of age have their vision checked by their pediatrician, family practitioner or an individual trained in vision assessment of preschool children. Any child who fails this vision screening should have a complete eye exam by an ophthalmologist (Eye M.D.).

If there is a family history of strabismus or amblyopia, or a family history of wearing thick eyeglasses, an ophthalmologist should check vision ever earlier than age 3. After a complete eye examination, an ophthalmologist can recommend appropriate treatment.

Strabismus Treatment

Treatment for strabismus works to straighten the eyes and restore binocular (two-eyed) vision. In some cases of strabismus, eyeglasses can be prescribed for your child to straighten the eyes. Other treatments may involve surgery to correct the unbalanced eye muscles or to remove a cataract. Patching or blurring the strong eye to improve amblyopia is often necessary.

Very young children with esotropia, glasses, exercises, patching or prisms may reduce or help control outward-turning of the eye in some children, surgery is often needed.

How is strabismus surgery done?

The eyeball is never removed from the socket during any kind of surgery. The ophthalmologist makes a small incision in the tissue covering the eye to reach the eye muscles.

The eye muscles are detached from the wall of the eye and repositioned during the surgery, depending on which direction the eye is turning. It may be necessary to perform surgery on one both eyes.

Recovery time is rapid. Children are usually able to resume their normal activities within a few days.

After surgery, glasses may still be required. In some cases, more than one surgery may be needed to straighten the eyes.

Strabismus Surgery

In some cases of strabismus in children and adults, strabismus treatment consists of glasses, prisms, patching or blurring of one eye, botulinum toxin injections, or a combination of these treatments. Other times, eye muscle surgery is necessary to straighten the eyes.

In children with some types of constant strabismus, early surgery may be recommended to improve the chance of restoring or promoting normal binocular vision.

In adults, eye alignment surgery is not strictly cosmetic. Cosmetic surgery is enhancement surgery, such as restoring youthful appearance in a normal aging person. Eye alignment surgery restores normal appearance and is considered reconstructive. There are many other benefits beyond restoring normal appearance: improved depth perception or binocular vision, improved visual fields, eliminating or minimizing double vision and improved social function – as eye contact is hugely important in human communication. It is important to discuss the goals and expectations of the surgery with your ophthalmologist (Eye M.D.).

During strabismus surgery, one or more of the eye muscles are strengthened, weakened or moved to a different position to improve alignment. Strabismus surgery is usually performed as an outpatient procedure and does not require an overnight hospital stay.

Preoperative tests for strabismus surgery

Before surgery, a specialized examination called a sensorimotor examination will be performed in the Eye’s M.D.’s office to assess the alignment of the eyes to determine which muscles are contributing to the strabismus and which muscles need to be altered (weakened, strengthened, or moved) to improve the alignment of the eyes. Prisms are used to measure the degree of the strabismus. These preoperative tests help guide the surgeon in determining the surgical plan. Often both eyes require surgery, even if only one is misaligned. Sometimes the exact surgical plan is determined based on finding at the time of the surgery, especially in reoperations.

Medications and strabismus surgery

Strabismus surgery rarely causes significant bleeding. However, some surgeons may suggest that you stop taking blood thinners, aspirin, aspirin-containing products, ibuprofen or certain nutritional supplements that can be affect bleed for a week before the surgery. Withholding these medications should also be discussed with the prescribing doctor to assess the rick of NOT taking the medication. If a pain medication is necessary during this time, acetaminophen (Tylenol) can be used as a substitute.

The strabismus surgery procedure

Strabismus surgery in children requires general anesthesia. Before surgery, a medication is often given to children to alleviate their anxiety of being separated from their parent. In adults, the procedure can be done with general or local anesthesia. Either way, the patient must fast for about eight hours before the procedure. For this reason, pediatric cases are often scheduled in the early morning.

The eye is never removed to perform the surgery. The eyelids are gently held open with a lid speculum. A small opening is made through the conjunctiva (the mucous membrane surface of the eye) to access the muscle. The muscle is then weakened, strengthened or moved to change its action with dissolvable sutures. Most strabismus surgeries are less than one to two hours; however, the patient will be at the surgery center for several hours including pre-operative and post-operative care.

Adjustable sutures

In standard strabismus surgery, the muscle is weakened, strengthened or moved and a permanent knot is placed. In adults, there is the added advantage that an adjustable suture can be used. Instead of a permanent knot, a temporary knot is placed. After the surgery, with the patient awake, alignment can be reassessed, and if necessary, adjustments can be made before a permanent knot is placed to minimize the chance of an over-correction or under-correction. This is typically done the day of or the day after the surgery.

After surgery

Any patient that has surgery, whether under general anesthesia or local anesthesia with sedation, needs to be monitored after surgery. Children can return to school after two days. Adults should not drive the day of surgery or the day after and may need up to a week before returning to work. You may have double vision that can last hours to days or a week or more, rarely longer. Exercise caution with activities like driving if you have double vision.

Pain is minimal and usually over-the-counter medicines, such as ibuprofen (Motrin) or acetaminophen (Tylenol), and cool compresses are adequate. Adults and older children may need prescription pain medicine.

The main restriction after strabismus surgery is not swimming for two weeks.

The eye will be red for one to two weeks, rarely longer, especially if it is a reoperation.

Eyelid Problems

Our eyelids play both a protective and an aesthetic role for our eyes. They lubricate and wash away irritants, shield eyes from bright lights and allow sleep, and frame the eyes and give us expression. If eyelids are misshapen, irritated or infected, vision may be impaired, or severe ocular damage can occur.

What are some common eyelid problems?
Dermatochalasis: droopy or baggy eyelids from excess skin.
Blepharoptosis (ptosis): drooping of the upper eyelid from a weak muscle.
Entropion: when the lower eyelid and lashes turn inward.
Ectropion: an abnormal lower eyelid that turns outward and no longer touches the eye.
Skin cancer: including basal cell carcinoma, squamous cell carcinoma, malignant melanoma, and sebaceous cell carcinoma. Treatment involves complete surgical removal of the cancer and reconstruction of the affected area.
Blepharitis: chronic redness, irritation and flaking of the eyelids.
Functional eyelid surgery provides treatment for the following:
Ptosis-drooping eyelid due to weak muscle
Dermatochalsis-excessive eyelid skin
Retraction-eyelid not able to close
Entropion-eyelid turns in
Ectropion-eyelid turns out
Skin cancer