Strabismus surgery is a procedure used to loosen and tighten eye muscles to improve the eyes' alignment and restore proper vision. Strabismus is a condition in which the eyes are misaligned so that they are unable to view the same object at the same time. The misalignment is due to the extraocular muscles (control eye movement) being either too weak or too stiff. Strabismus can either be congenital or may begin later in life.
The surgical procedure involves loosening, tightening, or moving specific extraocular muscles, to bring both eyes to alignment. A muscle that is too strong may cause the eye to turn out, in, or rotate too low or too high. In some cases, more than one surgical procedure may be performed to correct strabismus.
With misaligned eyes, the brain receives two different images. A person with normal vision will have images sent to both eyes where the brain combines them to one, 3-D image (depth perception). In children, the brain ignores the image from the affected eye and instead picks up the image from the adequately aligned eye causing loss of depth perception. In adults, the brain picks up images from both the aligned and misaligned eyes, leading to diplopia (double vision). Strabismus surgery's aim is to align the eyes so that they are both pointing in the same direction.
- Strabismus surgery involving recession and resection
- Adjustment suture strabismus
Before the Procedure
The doctor will take the patient's medical history, which includes family, medications, trauma, and previous ocular treatment. The patient will undergo extensive physical eye examinations which include visual acuity, ocular motility, pupillary exams, external exams, slit lamp examination, and many other tests. The ophthalmologist will also determine which muscles will be operated on. The procedure will be done in an outpatient setting.
Anesthesia administration depends on the age and health of the patient. For children, general anesthesia is preferred while adults may undergo general or local anesthesia.
In the recession/resection procedure, the surgeon:
- Keeps the eyelids open with an eyelid speculum
- Makes an incision into the conjunctiva to access the muscles of the eye
- Isolates the muscle(s) using a small instrument
- Places a suture through the muscle at the point of attachment to the eye
- Through a recession, detaches the muscle from the eye’s surface and reattaches it further back from the eye’s front. This action may be undertaken to weaken the muscle’s relative strength if it is too strong or reduce the strength of the antagonistic muscle if the muscle is too weak.
- Performs a resection by reattaching the lateral rectus muscle in a different location to strengthen it in case of an esotropia (inwardly turned eyes). Generally, in a resection procedure, the surgeon shortens the muscle and reattaches it to its original position on the eyeball to strengthen muscle function. The surgeon places a suture through the muscle at the new intended length. S/he removes or folds over a segment of the muscle located between the eyeball and the suture. The surgeon then reattaches the shortened muscle to the eye
- Ties a permanent knot instead of using adjustable sutures
In the adjustment suture strabismus procedure, the surgeon:
- After a resection procedure, further improves the final outcome by adjusting sutures that hold eye muscles in place. This procedure is performed only in adults who previously had properly aligned eyes but have acquired strabismus later in life
- Patches the eye which is later removed four to 24 hours later and evaluates ocular alignment
- Decides whether to tighten or loosen the suture on the treated muscle
- When satisfied that the eyes are correctly aligned, permanently ties the adjustable suture in place to complete the procedure
Risks & Complications
One most noticeable, dramatic side effect is redness in the surgical area after surgery, which may persist but should disappear in two weeks. Upon movement, the eyes will feel sore and scratchy. The soreness should improve a few days following surgery.
Blood-tinged tears are evident immediately after surgery, but these should clear in a few hours and do not affect the result. Mucous is also secreted excessively, and it accumulates in the eyelashes forcing the eyelids to stick together. The mucus can be wiped away with a clean, warm, moist piece of cloth.
Other risks and complications include:
- Infection which can spread to the deeper orbital tissues requiring aggressive antibiotic therapy
- Inflammation on the surface that may protrude between the eyelids (chemosis) and can last about three weeks
- Bruising may occur on the lids mostly in patients taking blood thinners and those undergoing repeated surgery
- Evidence of surgery may be noticeable such as a scar (incision), bluish discoloration on the sclera, a ridge on the sclera where the muscle was previously attached, and persistent redness
- Pain may last from a few hours to several days. The pain varies from person to person. Children experience less discomfort than adults because they are made to take a nap soon after the procedure. The adults may have minimal to moderate pain. The more muscles are involved, the more the pain and discomfort. Eye drops usually help to relieve pain and discomfort.
Aftercare & Recovery
The surgeon may prescribe antibiotics and steroid eye drops or ointment to be used for several days after the procedure. A follow-up visit will be undertaken a week or two after surgery. The next visit may happen a month to three months later. Patients who have undergone adjustable strabismus surgery are seen from the day of the surgery to seven days after surgery. The frequency depends on the technique that was used.
The patient should resume regular activities in a few days. S/he is advised to avoid potential eye contaminants such as soaps and shampoo for two to three days. The patient must also avoid swimming for several days. Some individuals may drive the day after surgery.
There should be eye alignment immediately or the first few days following surgery, a pointer to the final outcome. However, alignment may change as healing occurs. Permanent results should manifest four to eight weeks after the procedure. Double vision should resolve in a few days to weeks after surgery.
To maintain the best possible alignment, children younger than ten years may have to undergo two or three more procedures. Eyeglasses or prisms (special lenses) inserted in a pair of glasses may assist in binocular vision (both eyes working together).