Application of bifocal and progressive addition lenses in the management of accommodative esotropia: A comprehensive review of current practices

Nonrefractive accommodative esotropia (NRAET) is a form of pediatric acquired strabismus in which the accommodative convergence to accommodation (AC/A) ratio is high. Accordingly, the near angle of esotropia is notably greater than the distance angle, and after full-cycloplegic correction, the near angle is not fully resolved. Nonsurgical plans to deal with convergence-excess esotropia include observation only and single vision lenses with or without a ground-in plus addition power. Bifocals and progressive addition lenses (PALs) are two available designs when the preferred management approach is near plus addition. There are inconsistent data regarding the practical effectiveness of these two optical modalities in providing ocular alignment. Several studies advocated using bifocals and PALs as the primary management strategy in patients with NRAET; however, because of developmental concerns, others affirm that early surgical intervention can be a more conservative strategy than optical treatment. They noted that this method might be ineffective or even pernicious due to the need to defer the surgical intervention. In practice, the prescription of near plus addition lenses in the two forms of bifocals and PALs could be a double-edged sword in the treatment course of patients with NRAET. Therefore, an individualized approach according to the age, degree of refractive error, AC/A ratio, esotropia angle at distance and near, coexisting amblyopia, and parents' economic and cosmetic concerns would be important before choosing any treatment option.