We were asked about recurrence of strabismus that had been corrected by surgery in childhood. Strabismus is crossing of the eyes. The eyes of an individual with strabismus are not lined up properly and they point in different directions. It occurs when the muscles of the eyes are imbalanced.
Strabismus in people without Down syndrome
Strabismus is a common eye condition in children . Most adults who have strabismus have had it since childhood. However, some adults can develop strabismus in adulthood .
Strabismus in people with Down syndrome
Strabismus is a common condition in children with Down syndrome. In a study of 226 individuals with Down syndrome (mean age: 16 years), 23.4% had strabismus (Makateb et al., 2019 ). In another study with 455 adults with Down syndrome, 21.1% had strabismus (Krinsky-McHale et al., 2012 ). The study did not discuss whether the strabismus had started in childhood, had occurred in adulthood, or occurred after the person had previously had surgery.
Treatment may consist of:
Prescription of special eyeglasses to help focus and straighten the eyes. The prescription may include a prism that bends light rays. Prisms do not "fix" strabismus (they do not strengthen the muscles) but do allow the affected eye to align while the prism is being worn. Prisms are built into the eyeglass lens.
Temporarily reduce the use of the stronger eye through patching or using eye drops to blur the vision. The weaker eye is forced to strengthen over time.
Eye muscle exercises.
If there are not effective, surgery is recommended.
Surgery success and need for reoperation
In some individuals who undergo surgery, the strabismus recurs, and another surgery is considered.
Children: In a study of more than 11,000 children having strabismus surgeries between 2007 and 2013, about 7.5% required reoperations. The paper did not mention if any of the children had Down syndrome (Leffler et al., 2016 )
Adults: Surgery to correct strabismus is not always successful in adults either, or there can be a recurrence of strabismus at some time in the future. In a study from the American Academy of Ophthalmology in 2004, in adults without Down syndrome, it was reported that 21% of the adults who had surgery required reoperations (Mills et al., 2004 ).
Down syndrome: In a small study of children with Down syndrome, surgical success was achieved in 12 of 14 children (85.7%). Mean age at the time of surgery was 6.2 years (range, 1.2-24.9 years). The good postoperative alignment remained stable during a follow-up period of at least 6 months. Four children were stable over long-term follow up (4 years). There was no mention of need for reoperation (Yahalom et al., 2010 ).
I was not able to find a study assessing the success of strabismus surgery in adults with Down syndrome.
Should another operation be done?
I did not find data that specifically addresses whether anything can or should be done for an adult with Down syndrome who had a recurrence of strabismus after previous surgery. In addition, we have had little experience with our patients having surgery in adulthood, so I am limited in giving an informed opinion from our experience.
With those limitations in mind, I do offer some thoughts on the decision regarding additional treatment for strabismus recurrence:
For any treatment, surgical or otherwise, one must consider what will be the benefits and what are the risks?
What is the vision capability of the eye that crosses? Can that eye still contribute to the overall vision? If alignment is achieved, will the overall vision improve?
If improved vision cannot be achieved with surgery, will the surgery be primarily cosmetic (how the person looks)? The cosmetic benefit, even without vision improvement, is enough reason for some to consider surgery.
Will the surgery be successful? In the study cited above in adults (without Down syndrome) who had strabismus surgery, 21% did require reoperations but 79% did not. Unfortunately, I could not find data for adults with Down syndrome (Mills et al., 2004 ).
What are the risks of the procedure? What are the risks of anesthesia? Is it possible the person’s vision may be worse after surgery, particularly if he has compensated for the strabismus and surgery may alter that compensation?
What type of surgery should be done for a person who requires a reoperation? One study stated that the type of surgical treatment or approach for patients with residual or recurrent esotropia is controversial (Wang & Wang, 2014 ). When the surgical approach for a health problem is not clear for our patients, we discuss considering a second surgical opinion.
The American Academy of Ophthalmology website states: “It Is never too late to treat strabismus. You do not have to live with the discomfort and problems caused by misaligned eyes. With your ophthalmologist’s help, you can find a treatment for your strabismus.” Therefore, if one surgeon recommends against a procedure, a second surgical opinion may be informative.
This article was adapted from a Q&A developed in partnership with LuMind IDSC Foundation. This Q&A is available for free along with other Q&As at www.myDSC.org .