Question

My daughter was diagnosed with accomodative strabismus and amblyopia at 8 months. She is now 21 months. We have been patching for 2 hrs/day, and she has been wearing glasses since 8 months. She is corrected at focal points 3-4 feet away and farther. Closer in than 3-4 feet (1 meter or so) she crosses. Her prescription has been stregnthened once already when we told our doctor that she is still crossing at short focal points. My questions are:

1). Should the prescription be strengthened again since she is still crossing at short focal points? Or are bifocals sometimes recommended in cases like this? 2). What are the odds she will eventually develop binocular vision? 3). How old are the kids before they can give feedback to the MD about which prescription strength is best for them?

Thanks for your time/help.

(John Simkiss)

Answer:

Dear John,

Apparently, your child has convergence excess, i.e. that eyes cross only, or much more, when looking at near. Convergence excess carries a prognosis that is slightly worse than a standard esotropia, because it is difficult to treat by surgery or by bifocals. By surgery only the angle of squint that occurs when the child is looking in the distance can be corrected, not the angle when looking at near. Otherwise the child would get divergent (squinting outward) when looking in the distance and convergent when looking at near, and such variations may, for instance, lead to double vision later in life. After straightening the angle of squint at looking in the distance, the remaining angle of squint when looking at near can be corrected with a special operation whereby the belly of the muscle is sutured to the globe, preventing the eyes from turning in towards the nose. this operation is, however, more difficult to perform, and sometimes, in my experience, the sutures detach from the eyes after years.
As suggested by you, it can also be treated by wearing bifocals, because supplying the child with reading glasses will make it unnecessary for the child to focus when looking at near and, as focusing is tightly connected to convergence in the brain, the eyes will turn in less. This should only be tried, however, if some degree of binocular vision can be expected.

Yours truly,

(Herb Simonsz, MD, PhD)

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