The Eigenvalues of Strabismus


Sue Barry and I gave a joint lecture at ICBO in England last year which encompassed in part the emotional valence of strabismus, and she continues to blog elegantly about components of vision that we tend to take for granted.  McBain and colleagues in the U.K. just published an article in the British Journal of Ophthalmology that touches upon QOL issues for which conventional criteria for cure of strabismus is inadequate.  Only the abstract of the article is available through open access.

The article revolves around a questionnaire and provides this conclusion:  PCA revealed a 3-factor solution for the Expectations of Strabismus Surgery Questionnaire (ESSQ): (a) intimacy and appearance-related issues, (b) visual functioning, (c) social relationships. This 3-factor solution explained 59.30% of the overall variance in the ESSQ. Internal consistency, content and nomological and concurrent validity were considered acceptable.

Eigenvalues

I don’t fully understand the statistical analysis used in the paper, and chances are that unless you’re a mathematician or statistician you won’t fully grasp it either.  Irrespective of the eigenvectors involved, there are several important points noted in the body of the article.

1) The individual items of the questionnaire indicated that patients expected surgery to lead to considerable improvements, primarily in relation to the appearance of their eyes as well as vision, and more specifically double vision. Research, however,does suggest that only 24% of patients with strabismus are successfully realigned post surgery according to clinical criteria; while 38% are classified as partial successes or failures. This might be because the patient requires prism therapy or a patch that was not necessary prior to surgery.  They still have a large deviation, or are experiencing double vision, visual confusion or other related visual symptoms that may have developed after surgery.

2) Of the 124 participants with diplopia prior to surgery in this study, one patient expected their double vision to worsen, 7% expected their diplopia to remain the same and all others expected their double vision to improve. Research does, however, suggest that double vision can remain in approximately two-thirds of patients up to 6 months post surgery, with almost one-fifth of patients with horizontal residual deviations still finding diplopia problematic in daily life.  This highlights a possible discrepancy between what the patients expect in relation to their double vision prior to surgery and what may actually happen. This potential discrepancy could contribute towards poor quality of life or poor satisfaction post surgery, and is particularly pertinent considering that patients appear to be more successfully aligned according to clinical criteria as opposed to quality of life outcomes.

the-bottom-line

The bottom line is this:  patients with strabismus often have expectations for life after strabismus surgery that isn’t fully anticipated by their surgeons.  Might collaboration with optometrists skilled in working with many of these visual factors result in better outcomes addressing these quality of vision and life factors?

2 thoughts on “The Eigenvalues of Strabismus

  1. “…patients with strabismus often have expectations for life after strabismus surgery that isn’t fully anticipated by their surgeons.. ” Are the majority of candidates for surgery presenting with an awareness of their impaired stereo vision and the fact that surgery does not address the underlying neurological issues, or are surgeons leading candidates on, whether by omission or blantly, towards a belief that surgery will address all their issues?

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