Dr. Libby Hackenberg
Unit 107 10055 120 Avenue
Grande Prairie, Alberta T8V 8H8
Tel: (780)532-1149 Fax: (780)532-1147
General and Pediatric Ophthalmology
Frequently Asked Questions
What is Strabismus?
Strabismus is a visual problem in which the eyes are not aligned properly and point in different directions. One eye may look straight ahead, while the other eye turns inward, outward, upward, or downward. The eye turn may be consistent, or it may come and go. Which eye is straight (and which is misaligned) may switch or alternate.
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. The other four muscles move it up or down and at an angle.
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.
How is Strabismus Surgery Performed?
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.
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.