Risks and complications of strabismus surgery

Strabismus surgery has established complications, including surgery on the wrong eye, infections, and death, which are discussed below. It is also common for repeated surgeries to be performed. It is important to note that the risk of complications is present with each repeated surgery.

Images of complications are not shown here since most readers find them gruesome and distracting but images can be found by searching in google images.

Death

Death has been a reported complication of Strabismus surgery and eye surgery in general. Pulling on the eye muscles during Strabismus surgery engages the oculocardiac reflex which slows the heart beat and can cause cardiac arrest - this has killed the patient in a few reported cases:

Arndt GA, Stock MC. Bradycardia during cold ocular irrigation under general anaesthesia: an example of the driving reflex. Can J Anesth 1993; 40:511-14.
Lang SA, Van der Wal M. Death from the oculocardiac reflex (Letter). Can J Anaesth 1994; 41:161.
Sorenson EJ, Gilmore JE. Cardiac arrest during Strabismus surgery. Am J Opththalmol 1956; 41:748-52.
Kirsch RE, Samet P, Kugel V, Axelrod S. Electrocardiographic changes during ocular surgery and their prevention by retrobulbar injection. AMA Archives of Ophthalmology 1957; 58:348-56.
Bietti GB. Problems of anesthesia in Strabismus surgery. Int Ophthalmol Clin. 1966; 6: 727-37

Modern methods and practices of anaesthesia may have reduced the risk of death and it is best for those considering Strabismus surgery to discuss the risk with your surgeon and anesthesiologist. One author puts the mortality rate of Strabismus surgery at 1.1 per 10,000 cases: Von Noorden, Gunter K. Binocular vision and ocular motility: theory and management of Strabismus, 4th ed, Mosby: 1990.

Surgery on the wrong eye or wrong patient

Surgical confusions continue to occur in ophthalmology. These include surgery done on the wrong eye, on the wrong muscle, on the wrong patient, and for the wrong surgical indication.

Blindness and accidental damage to parts of the eye

It is possible to damage the eye in many different ways during Strabismus surgery. Documented problems include orbital hemorrhage from the vortex vein or by damage to the sclera or optic nerve. Sometimes a part of the eye know as Tenon's capsule is perforated during surgery causing inflammation and an undesirable process called "fat adherence".

The sclera (the white part of the eye) may also be accidentally damaged or "perforated" during surgery. This may be associated with damage to the retina (the membrane that sends visual information to the brain) which can cause blindness. If the retina is damaged, separate surgery is require to fix it.

Another complication that can cause blindness is ischemia of the anterior segment which is lack of blood supply going to the front of the eye; this happens when the blood flow in the eye is accidentally disrupted during surgery. The condition can become severe and lead to necrosis or "death" of the tissue of the front part of the eye and blindness.

Infections, inflammations and more surgery to fix them

Orbital cellulitis, an acute infection of the tissues immediately surrounding the eye, including the eyelids, eyebrow and cheek can occur after Strabismus surgery. The bacteria involved in the infection are usually staphylococcus, streptococcus, or pneumococcus. Antibiotics work in about half the cases of infection. For the other half, hospital admission is required specifically for the infection. Sometimes an MRI is required to find the cause of the infection and if the cause turns out to be an infected surgical suture, more surgery is done to try to fix the problem.

Orbital cellulitis can even lead to blindness, as reported by a group of surgeons in a case report published in the journal Ophthalmic Plastic and Reconstructive Surgery in 2006.

Slipped or lost eye muscles

Strabismus surgery detaches, cuts and reattaches eye muscles. Sometimes the eye muscles are not adequately reattached during the surgery. This may cause the muscles to detach and slip. Sometimes, even in a subsequent surgery to fix the problem, the eye muscle cannot be found - this is called a "lost" muscle". This complication is sometimes discovered during the Strabismus surgery itself. Other times it is found only after surgery when the eye turn returns or the eye rotation is not functioning properly. Children with this problem may become unsteady and disoriented while adults may have double vision.

Scars and wound problems - large cysts and more surgery

Even if none of the above complications occur, there can be complications with the incision that the surgeon makes into the eye during surgery. One such problem is a conjunctival cyst which can appear in the first few days of surgery or even many years after surgery. Larger cysts, sometimes even larger than the eye, arise at the part of the eye where the eye muscle was reattached during Strabismus surgery. Usually, steroids or more surgery are required to treat these larger cysts.

The sutures used in surgery frequently cause problems even if the patient is not allergic to the suture material. A patient will usually experience redness and discomfort around the operated muscle for 11 weeks following surgery.

Repeated Surgeries and risk of anesthesia in young children

Surgeon John W. Simon notes one particular complication that is both very common and also of great concern to patients and their parents, "patients must regularly contend with the unfortunate reality that even the most accurately planned and carefully executed surgery may not totally eliminate the deviation [i.e. the misalignment of the eyes] or completely normalize rotations. In addition, Strabismus tends to recur over time." This limitation of surgery often results in the the patient being subjected to repeated surgeries - all of which may be unsuccessful. It is not uncommon for a patient to have had two or three or more surgeries and still have a noticeable misalignment or poor binocular vision together with depth perception problems or all three.

Now, recent scientific research is questioning the safety of doing repeat surgeries on young children. A number of recent studies have linked repeat surgeries that require anesthesia - like Strabismus surgery - to an increased risk of developing attention deficit/hyperactivity disorder (ADHD) and learning disabilities. The latest study, published in January 2013 linked even a single childhood exposure to anesthesia increased risk of learning disabilities later in life. Click here to learn more.

Low Success Rates

One study found that only 45% of children had successful alignment of the eyes at an eight-year follow up to their Strabismus surgery. And while the low percentage was disappointing enough, 20% of the children had to undergo repeat Strabismus surgeries which were ultimately unsuccessful: Awadein A, Sharma M, Bazemore MG, et al. Adjustable suture Strabismus surgery in infants and children. J AAPOS 2008; 12:585–590.

Another study looked at long term outcomes to determine how surgery patients fared 10 years after their surgery. The authors noted that 62% of strabismus (intermittent exotropia) surgery patients achieved only a fair or poor outcome and that 60% of the patients required at least one re-operation. They also went on to state that long-term surgical results in intermittent exotropia are less encouraging when sensory status outcomes (fusion) are taken into consideration. See: Pineles SL, Ela-Dalman N, Zvansky AG, Yu F, Rosenbaum AL.Long-term results of the surgical management of intermittent exotropia. J AAPOS. 2010 Aug;14(4):298-304.

Sources:

Simon, John W. Complications of Strabismus Surgery. Current Opinion in Ophthalmology 2010, 21:361–366

Awadein A, Sharma M, Bazemore MG, et al. Adjustable suture Strabismus surgery in infants and children. J AAPOS 2008; 12:585–590.

Hoyama E, Limawararut V, et al. Blinding Orbital cellulitis: A complication of Strabismus surgery.Ophthalmic Plastic and Reconstructive Surgery, Vol. 22. No. 6, pp472-499.

Arndt GA, Stock MC. Bradycardia during cold ocular irrigation under general anaesthesia: an example of the driving reflex. Can J Anesth 1993; 40:511-14.

Lang SA, Van der Wal M. Death from the oculocardiac reflex (Letter). Can J Anaesth 1994; 41:161.

Sorenson EJ, Gilmore JE. Cardiac arrest during Strabismus surgery. Am J Opththalmol 1956; 41:748-52.

Kirsch RE, Samet P, Kugel V, Axelrod S. Electrocardiographic changes during ocular surgery and their prevention by retrobulbar injection. AMA Archives of Ophthalmology 1957; 58:348-56.

Bietti GB. Problems of anesthesia in Strabismus surgery. Int Ophthalmol Clin. 1966; 6: 727-37

Pineles SL, Ela-Dalman N, Zvansky AG, Yu F, Rosenbaum AL.Long-term results of the surgical management of intermittent exotropia. J AAPOS. 2010 Aug;14(4):298-304.

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Did you know?

T

"Today, a relatively small group of optometrists still practice and continue to perfect optometric vision therapy techniques. Yet, it is difficult for a strabismic patient to learn about, much less access, this type of clinician."

Dr. Susan Barry, 2010 Journal of the American Optometric Association

Quotable

There has been an explosion of research into the optometric treatment of the visual symptoms following concussions by using vision therapy and rehabilitation.

There have been so many studies demonstrating the effectiveness of these approaches and clinics like our's across North America are making a big difference in the lives of concussion patients. Here is a passage from a recent article by Dr.Neera Kapoor.

Quotable

In an 2008 study published in the journal, Optometry, that studied oculomotor dysfunctions in acquired brain injury, the researchers concluded that, "[n]early all patients in the current clinic sample exhibited either complete or marked reduction in their oculomotor-based symptoms and improvement in related clinical signs, with maintenance of the symptom reduction and sign improvements at the 2- to 3-month follow-up. These findings show the efficacy of optometric vision therapy for a range of oculomotor abnormalities in the primarily adult, mild brain-injured population. Furthermore, it shows considerable residual neural plasticity despite the presence of documented brain injury."