Accommodative ET-High AC/A Ratio Esotropia: The Case for Glasses

Abstract

Background and Purpose

There is a continuing debate as to whether the patient optically correctable at distance to within 8 prism diopters of perfect alignment requires treatment for persisting overconvergence at near, and if treatment is indicated, what it should be.

Patients and Methods

For the patient whose misalignment at distance is reduced to 8 or fewer prism diopters, my preference is for the full cycloplegic correction plus a bifocal in the first prescription, to discourage virtually all accommodation initially, with pull back later.

Results

Review of several reports indicates a continued lack of consensus on whether this causes disuse weakening of accommodation and premature presbyopia. Recent studies found that prolonged convergence tone at near can result in anatomic and physiologic alterations in the medial rectus muscles that threaten a satisfactory distance alignment as well, despite relief of the accommodative demand. Hypoaccommodative esotropia resembles the high AC/A variety.

Conclusion

Spontaneously improving over-convergence at near is not likely to occur in the hypoaccommodating patient either with observation alone or with surgery. I reserve surgery for the over-convergence at near for the unusual case of an extremely high distance-near disparity, and for the teenager or adult not showing likelihood that the condition will resolve.

• accommodative esotropia
• high AC/A ratio
• abnormal distance-near alignment comparison
• hypoaccommodation
• bifocals