Purpose:
The purpose of this study was to evaluate the near point of convergence break in Turkish population with normal binocular vision and to obtain the normative data for the near point of convergence break in different age groups. Such database has not been previously reported.
Material and Method:
In this prospective study, 329 subjects with normal binocular vision (age range, 3-72 years) were evaluated. The near point of convergence break was measured 4 times repeatedly with an accommodative target. Mean values of near point of convergence break were provided for these age groups (≤10, 11-20, 21-30, 31-40, 41-50, 51-60, and >60 years old). A statistical comparison (one-way ANOVA and post-hoc test) of these values between age groups was performed. A correlation between the near point of convergence break and age was evaluated by Pearson’s correlation test.
Results:
The mean value for near point of convergence break was 2.46±1.88 (0.5-14) cm. Specifically, 95% of measurements in all subjects were <6 cm. There were statistically significant differences, which were found between the age groups of ≤10 years old and 21-30, 31-40, 41-50, 51-60, >60 year-old age groups in the near point of convergence break values (p=0.0001, p=0.0001, p=0.006, p=0.001, p= 0.004). A mild positive correlation was observed between the increase in near point of convergence break and increase of age (r=0.355) (p<0.001).
Discussion:
The values derived from a relatively large study population to establish a normative database for the near point of convergence break in the Turkish population with normal binocular vision are in relevance with age. This database has not been previously reported.
Keywords: Near point of convergence break, normative data, convergence insufficiency