Relationship between myopia severity, near exophoria, vergence, and accommodation amplitude in children

To investigate the relationship between myopia severity, near exophoria, near point of convergence (NPC), and accommodation amplitude (AA) in children.

This descriptive, cross-sectional, hospital-based study included 117 myopic children with a mean age of 11.32 ± 2.87 years. Refraction was measured with an autorefractometer and confirmed by retinoscopy. Slit-lamp biomicroscopy and ophthalmoscopy were performed to ensure participants met the study's inclusion criteria. AA and NPC were measured using a Royal Air Force ruler. Near exophoria was assessed with a prism bar and cover test.

Of the 117 myopic children, 95 (81.2%) had a parental history of myopia, with no significant difference between genders (P = 0.185). The mean myopic spherical equivalent was -1.76 ± 0.90 D in the right eye and -1.79 ± 0.97 D in the left eye (P = 0.277). A significant positive correlation was found between near exophoria and the spherical equivalent of myopia (r = 0.281**, P = 0.002). Positive but nonsignificant correlations were observed between monocular (r = 0.086) and binocular (r = 0.118) accommodation amplitudes with myopia severity (P > 0.05). Conversely, a weak inverse correlation (r = -0.020) was found between the NPC and the severity of myopia, which was not statistically significant (P = 0.833).

The study found a significant positive correlation between near exophoria and the severity of myopia in children, suggesting that binocular vision anomalies may contribute to myopia progression or that myopia itself may influence near exophoria. Therefore, comprehensive eye examinations for myopic children should include binocular vision assessments to guide effective management strategies.