Prevalence, risk factors and clinical features of sensory A-V pattern exotropia

To investigate the potential mechanisms of A-V pattern and evaluate the surgical outcomes used in the treatment of sensory exotropia.

The medical records of patients with sensory A-V pattern exotropia who underwent strabismus surgery between May 2014 to June 2019 was retrospectively reviewed. The control group included sensory exotropia patients without A-V pattern and concomitant A-V pattern exotropia patients with normal vision who undergone strabismus surgery over this same time period. Ocular alignment, best corrected visual acuity, oblique muscle function, and stereopsis records were collected.

Among the 843 eligible patients, 91 (10.79%; 39 males and 52 females) had A-pattern (54, 6.4%) or V-pattern (37, 4.4%). Age at onset of vision impairment was 4±5y and at the time of surgery was 25±9y. Statistically significant negative correlations were present between impaired visual acuity and the pre-operative exodeviation (r=-0.198, P=0.016) and patterns (r=-0.207, P=0.015). Age at surgery and exodeviation in patients with concomitant A-V pattern exotropia was significantly earlier as compared with that of sensory A-V pattern exotropia and sensory exotropia (both P<0.0001). There were no significant differences in these clinical variables between sensory exotropia with or without A-V pattern. Deviation and pattern were significantly reduced in patients receiving horizontal rectus surgery with or without oblique muscle surgery (both P<0.0001).

The prevalence of sensory A-V pattern exotropia in our study is 10.79%. Visual acuity represents an important factor contributing to the occurrence and development of A-V pattern. Isolated horizontal rectus surgery can provide a good option for the correction of sensory A-V pattern exotropia.