To investigate the frequency and associated factors of accommodation and non-strabismic binocular vision dysfunction among medical university students.

Totally 158 student volunteers underwent routine vision examination in the optometry clinic of Guangxi Medical University. Their data were used to identify the different types of accommodation and non-strabismic binocular vision dysfunction and to determine their frequency. Correlation analysis and logistic regression were used to examine the factors associated with these abnormalities.

The results showed that 36.71% of the subjects had accommodation and non-strabismic binocular vision issues, with 8.86% being attributed to accommodation dysfunction and 27.85% to binocular abnormalities. Convergence insufficiency (CI) was the most common abnormality, accounting for 13.29%. Those with these abnormalities experienced higher levels of eyestrain (χ²=69.518, P<0.001). The linear correlations were observed between the difference of binocular spherical equivalent (SE) and the index of horizontal esotropia at a distance (r=0.231, P=0.004) and the asthenopia survey scale (ASS) score (r=0.346, P<0.001). Furthermore, the right eye's SE was inversely correlated with the convergence of positive and negative fusion images at close range (r= -0.321, P<0.001), the convergence of negative fusion images at close range (r=-0.294, P<0.001), the vergence facility (VF; r=-0.234, P=0.003), and the set of negative fusion images at far range (r=-0.237, P=0.003). Logistic regression analysis indicated that gender, age, and the difference in right and binocular SE did not influence the emergence of these abnormalities.

Binocular vision abnormalities are more prevalent than accommodation dysfunction, with CI being the most frequent type. Greater binocular refractive disparity leads to more severe eyestrain symptoms.

To explore the risk factors for acute acquired comitant esotropia (AACE).

A retrospective cohort study was conducted by analyzing 83 patients (case group) with AACE who underwent strabismus correction surgery from January 1, 2021 to June 30, 2022. Totally 73 outpatient volunteers were recruited during the same period as the normal control group. The case group’s binocular vision time, near and distance esotropia angle, and near stereo vision function were recorded, and the age, gender, refractive status, and best-corrected visual acuity (BCVA) of both groups were analyzed. Additionally, multiple logistic regression analysis was conducted using an eye usage condition questionnaire to determine the independent risk factors for AACE.

In the case group, 61 patients (73.49%) had myopia, with a mean equivalent spherical power (SE) of -3.35±3.31 D (range: +2.75 to -10.62 D) of the right eye and -2.87±3.35 D (range: +2.75 to -11.12 D) of the left eye. The average duration of diplopia in the case group was 29.83±35.72mo, of which 80 patients (96.39%) were primarily with distance diplopia. The near and distance esotropia angle after wearing glasses were 52.36±20.95 prism degree (PD) and 56.71±19.54 PD, respectively, and there was no statistically significant difference between the two (t=1.38, P=0.169). The incidence of improper glasses wearing and unhealthy eye habits in the case group was significantly higher than those in the control group (P<0.05). Close-up work without glasses [β=2.30, odds ratio (OR)=10, 95% confidence interval (CI) 2.35-42.51, P=0.002] and near work in supine position (β=1.80, OR=6.02, 95%CI 3.29-11.02, P<0.001) were independent risk factors for AACE.

Patients with AACE mainly present with distance diplopia, and there is a high degree of variation in myopia. Near work without wearing glasses and in supine position are independent risk factors for AACE.