Refractive error and angle of deviation in basic esotropia versus exotropia: a comparative study

To compare refractive error and angle of deviation in patients with basic esotropia and basic exotropia.

A retrospective review was conducted on the medical records of patients with basic-type strabismus. Demographic data, refractive error, best-corrected distance visual acuity (BCVA), and the horizontal and vertical angle of deviation between basic esotropia and exotropia patients were compared.

Among the 7129 patients (mean age 22.98±14.81y) evaluated, 44.7% (3185 cases, 54.9% male) exhibited basic-type esotropia, while 55.3% (3944 cases, 53.9% male) presented with basic-type exotropia. Basic esotropia cases exhibited more hyperopic spherical equivalent measurements in both eyes (right: 0.53±3.07 vs left: 0.56±2.98 D) than those with basic exotropia (right eye: -0.33±2.84 vs left eye: -0.24±2.68 D, P<0.001 for both eyes). Patients with basic esotropia had significantly greater horizontal deviation angles (near: 36.08±18.87 PD and far: 35.56±18.75 PD) compared to those with basic exotropia (near: 33.75±16.11 PD and far: 33.26±15.90 PD, P<0.001). Conversely, patients with basic exotropia had slightly higher vertical deviation angles (near: 1.67±5.80 PD and far: 1.72±5.89 PD) compared to those with basic esotropia (near: 1.12±4.57 PD and far: 1.12±4.58 PD, P<0.001). Patients with basic esotropia underwent surgical intervention at younger ages compared to basic exotropia individuals (19.68±15.99 vs 25.66±13.20, P<0.001).

Basic esotropia patients present more hyperopic refractive errors, better visual acuity, larger horizontal yet smaller vertical ocular misalignments, and tend to undergo strabismus surgery at younger ages relative to basic exotropia cases.