Intractable Diplopia: Fact or Fiction?

Taylor & Francis

Taylor & Francis publishes Strabismus – a quarterly journal online out of the UK that frequently contains  thought-provoking articles.  The current issue is no exception, and features free access to an article on Assessment of the Density of Suppression to Identify Risk of Intractable Diplopia in the United Kingdom. (For those not familiar with the term, intractable diplopia is double vision that won’t go away.)

The article is noteworthy for multiple reasons.  One is the widespread disparity among orthoptists in assessing the relative risks for intractable diplopia, both in terms of methodology and age factors.  Even more insightful are the speculations at the conclusion of the article, and I’ll list a number of them:

  1. Although the risk of intractable diplopia induced by treatment is modest, the reported incidence may be  underestimated due to the reluctance of respondents to admit to having induced intractable diplopia.
  2. For the individuals involved, however, intractable diplopia has substantial quality-of-life implications.
  3. It is possible that “latent” cases may be caused where a reduction in density of suppression occurs during treatment without diplopia, but patients then present later in life with intractable diplopia.
  4. The issue of intractable diplopia and amblyopia treatment may take on greater significance given the impetus to treat teenagers and adults in light of visual neuroplasticity.
  5. When improving acuity in older children and adults with amblyopia via dichoptic methods to reduce suppression and improve binocularity, there is no evidence that the increase in plasticity reported will enable suppression to be regained if fusion is not possible.
  6. It is likely that in current practice, amblyopia treatment in some children is either being unnecessarily withheld due to the perception of a risk that does not exist, or perhaps more likely some are at risk yet the true extent is not yet known.

5 thoughts on “Intractable Diplopia: Fact or Fiction?

  1. Another consideration to rule our is that since we are extending further out into later ages for amblyopia tx, we may also be hitting another condition termed sensory fusion disruption syndrome where those with a traumatic brain injury may be seeing diplopia as well. Rick London suggests these are two different conditions(one developmental, one acquired). I’ve seen two intractable diplopia cases that were post surgical AC cases. They were retrained to increase suppression density(?) and thus we eliminated the diplopia.

    • Points well taken, Curt – and thanks for sharing the observation. A few times in my career I have worked to help the patient recapture better suppression rather than persist with the con-fusion presented by binocularity, as much as it felt like heresy. This is also what has led to me work on MFBF as a middle ground in select cases, embedding central suppression while preserving and strengthening peripheral fusion – very valuable in avoiding diplopia.

  2. I see too many of these patients who have diplopia after acquired brain disorders and then have had strabismus surgery for ocular motor palsy. Many of them will regain fusion with treatment, but not all. I have used monovision (lenses with training) as an alternative to dense suppression. Not my favorite thing, but it does help the patients a lot and that is what we are here to do.

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