The Association Between Angle Alpha Magnitude And Strabismus In Cataract Surgery Patients

To Investigate the association between iTrace angle alpha magnitude measurements and strabismus among patients evaluated for cataract surgery.

Mayo Clinic Department of Ophthalmology Rochester, MN USA.

Angle alpha magnitude measurements using the iTrace (Tracey Technologies Houston, TX USA) in patients evaluated for cataract surgery from November 1, 2014, through February 28, 2018, segregated by the presence or absence of strabismus, were reviewed retrospectively using the EPIC Clarity database.

Among 8,179 patients evaluated for cataract surgery, the mean angle alpha for the 8,068 non-strabismic patients was 0.42 millimeters compared to 0.44 mm for the 111 strabismic patients (p = 0.26). When stratified by strabismus types of esotropia, exotropia, hypertropia, convergence insufficiency, and divergence insufficiency, hypertropia (n = 17) was the only subgroup to demonstrate a significantly larger mean angle alpha compared to those without strabismus (0.48 vs. 0.42 mm; p = 0.01).

Although most strabismus patients seeking cataract surgery in this cohort did not demonstrate angle alpha magnitudes significantly different from those without strabismus, preliminary evidence suggests that patients with hypertropia have a larger than normal angle alpha. Further investigation with a larger cohort would be appropriate to better assess whether specific strabismus diagnoses are associated with elevated angle alpha magnitudes.