Discussion A previous study has shown that 14.5% of adolescents aged 717 years meet the criteria for at least one MD related to mental impairment, and the comorbidity rate of MDs in children and adolescents is higher than that in adults . Another study showed that anxiety disorders are the most common MDs in adolescents, followed by behavioral, affective, and substance use disorders . Table 3 Ocular disorders with MDs and control group MDs group(n = 178) n% Control group(n n% = Conjunctivitis 24(13%) 10(5%) Keratitis 12(7%) 3(2%) Optic disc edema 1(0.5%) 0 Corneal endothelial dystrophy 1(0.5%) 0 Trichiasis 7(4%) 3(2%) IOL implantation 2(0.5%) 0 IOL intraocular lens 200) Page 5 of 7 Table 4 Odds ratios for risk factors for refractive error, amblyopia, and strabismus in adolescent with mental disorder by multiple logistic regression Risk factor Odds ratios (95% confidence interval) Significant refractive error Amblyopia Strabismus Depression

Mental retardation Emotional disorders Adjustment disorder 3.617 (0.869, 15.06) N/A 2.091 (0.995, 4.395) 4.415 (0.958, 20.348) 1.885 (1.583, 49.857) P 0.013 = 3.286 (3.974, 136.456) P 0.001 = 2.003 (1.792, 20.108) P 0.004 = 2.629 (3.223, 107.687 P 0.001 = 1.362 (2.256, 24.019) P 0.001 = N/A 2.205 (3.386, 11.372) P 0.001 = N/A However, our study showed that emotional disorders were the most common (46%), followed by anxiety and depression.

MDs or mental health problems during adolescence increase the risk of vision problems in early adulthood. The present study analyzed the spherical diopters, cylindrical diopters, and the prevalence of anisometropia in adolescents with MDs as well as a control group. Refraction is generally performed following cycloplegia or noncycloplegia. For children and adolescents under the age of 15 years, cyclopentolate hydrochloride (1%) was used to evaluate the refractive status and corrected visual acuity. We found that the MD group was significantly more susceptible to astigmatism than the control group. Nielsen and Das reported a higher prevalence of hypermetropia and astigmatism in adolescents with a developmental delay than in normal adolescents [12, 13]. Chang et al. reported that the prevalence of high myopia was 4.1% and high astigmatism was 19.8% among Taiwanese students with cognitive impairment aged 1523 years . However, we found that the prevalence of high myopia was 11

.2% in the MD group, similar to that in the control group (10%). The prevalence of myopia in the MD group was not higher than that in the control group. Moreover, the age range was 618 years old, covering the age at which myopia is expected to occur. Yan et al. found that a decline in near stereoacuity can result in significant anxiety and depression . Visual impairment and loss of binocular function are related to symptoms of anxiety and depression . The stereoacuity results in our study largely agreed with their views.