In Part 1 we cited a classic difference of professional opinion between ophthalmology and optometry regarding eye muscle surgery for strabismus. Here’s another case that typifies some of the discussions on VTPU about which parents feel conflicted. This one involves Efraim, a five year-old, who I saw for the first time in my office a couple of weeks ago. There is a strong family history of strabismus, so his parents have been vigilant about his eyes. They reported first noticing that his left eye periodically turning inward and upward last year, and he has considerable disinterest in learning to read. After taking him to the surgeon who operated on his siblings, they received this summary:
So what’s the difference of opinion here?
If a child’s eye turns inward and upward, but doesn’t do so until 3 inches from the the face, he doesn’t have a binocular problem as long as sensory fusion is normal. How do ophthalmologists test sensory fusion in a 5 year-old? Most likely only by their ability to correctly identify the Random Dot E. But does that really provide evidence of sufficient fusion to sustain the demands of near tasks such as reading? The thinking, and this prevalent with every pediatric ophthalmologist I’ve encountered (particularly when the deviation is eso or hyper rather than exo) is that this has no bearing on reading performance unless it occurs constantly as the reading distance.
But recall the parents’ history. They do see the eye periodically turning inward and upward, and they aren’t making this observation at a 3 inch viewing distance! And they are very good historians, and understand when strabismus is present and when it isn’t, given the family history with other siblings. So I would trust the parents’ report in this instance that the strabismus is occurring at some times at the child’s reading distance (which for a 5 year-old is around the 10-12 inch distance). As we know, the variability in fusion often results in more instability and confusion than a constant strabismus in which there is lack of fusion (con-fusion is often more disruptive than no-fusion). They’re not comfortable with the advice to do nothing unless the misalignment becomes bad enough to require strabismus surgery. Low plus, yoked prism, and binasal occlusion might be just what the doctor should order here.