Effects of different types of refractive errors on bilateral amblyopia

Objectives: Identifying effects of different types of refractive errors on final visual acuity and stereopsis levels in patients with bilateral amblyopia. Materials and methods: Patients with bilateral amblyopia lower than ≥1.5 D anisometropia were included. The patients were classified according to the level of spherical equivalent (0-4 D and >4 D of hypermetropia), the level of astigmatism (below and above 2D in positive cylinder) and type of composed refractive error [<4 D of hypermetropia and < 2 D of astigmatism (group I), > 4 D of hypermetropia and < 2 D of astigmatism (group II), and < 4 D hypermetropia and > 2 D of astigmatism (group III)]. Initial and final binocular best corrected visual acuities (BCVA) were compared between groups. Results: The initial binocular BCVA levels were significantly lower in patients with > 4 D of hypermetropia (p=0.028), without correction after treatment (p=0.235). The initial binocular BCVA was not different between astigmatism groups, but final BCVA levels were significantly lower in 4-6D of astigmatism compared with 2-4 D of astigmatism (p=0.001). During comparison of composed refractive errors, only the initial binocular BCVA was significantly lower in group I compared to group II (p=0.015). The final binocular BCVA levels were not different between groups I and III (p>0.05). Conclusions: Although the initial BCVA is lower in patients with higher levels of hypermetropia, the response of patients to treatment with glasses is good. The response of patients with high levels of astigmatism seems to be limited.