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	At near fixation on an accommodative target and picture, the ET measures 45 PD.		At distance fixation, the child demonstrates a 5 PD XT.

This 3-year-old girl was examined by another doctor who prescribed glasses as follows:  OD + 3.25 + 1.00 x 90 and OS +2.75 + 1.00 x 100.  She wears her glasses well, but the family is worried because her eyes turn out a little in the distance and turn in a great deal at near.  Without glasses she measures 15 PD esotropia at the distance and 55 PD esotropia at near.  At this examination the girl does not demonstrate fusion, but this is difficult to measure in the distance.  Cycloplegic refraction is as she is wearing.  Versions and ductions are normal.  The media are clear and the posterior pole is normal.  The child does not complain of diplopia.  On careful questioning, the family states that the eyes began to cross about six months ago.  The girl is otherwise healthy and there is no family history of strabismus.

1.	The most likely diagnosis is:
	a -- refractive/accommodative esotropia This is called a refractive accommodative esotropia because both the uncorrected refractive error and the accommodative effort contribute to the eso-alignment.
2.	The most likely cause of this strabismus is:
	d -- high AC/A The child has a high accommodative convergence / accommodation ratio or AC/A.  This causes more than the normal or needed amount of convergence when accommodating on a near object.
3.	An appropriate treatment would be:
	c -- reduce the plus in the distance until the eyes are aligned and prescribe a bifocal add strong enough to align the eyes at near It would be best to reduce the plus correction at the distrance until her eyes are aligned viewing an accommodative target in the distance.  At near the plus correction would be increased by adding plus lenses until the eyes are aligned or until a +3.50 lens has been held over the proper distance correction.  Even if there were a little residual ET with a + 3.50 addition, the girl would benefit from a trial of bifocals.  If bifocal correction does not result in alignment, Phosphoiline Iodide drops could be added.  These are given once a day three or more times a week (maybe less) titrating as needed.  The child should be checked for fusion at each follow-up visit.  If all else fails, she could be a candidate for a bilateral faden of the medial rectus muscles.