title: Prevalence of astigmatism in a paediatric population with malocclusions.
abstract: OBJECTIVE
  The purpose of this study was to investigate the prevalence of astigmatism among a paediatric population.
  
  
  METHODS
  A total of 322 consecutive patients of the department of Orthodontics and Gnathology, Dental Clinic, University of L'Aquila, were enlisted for the study and 176 were selected according to the exclusion criteria. Pre- treatment diagnostic data, which included radiographic cephalometric and dental cast evaluation, were recorded and presence of astigmatism was assessed through an ophthalmological examination. Differences in the prevalence of astigmatism by sex and malocclusion were analysed by using the chi-square (Pearson's chi-square test) and Fisher's exact tests.
  
  
  RESULTS
  According to the sagittal malocclusion, patients were classified as Class I (N=122), Class II Division 1 (N=26), Class II Division 2 (N=9), or Class III (N=19); according to the transverse malocclusion patients were classified into cross-bite (N=39) and no cross-bite (N=137) groups; after ophthalmological examination astigmatism was detected in 32 patients (18.18%). Statistically significant correlations were found between astigmatism and cross-bite (p < 0.0001), while no associations were found with other malocclusions. No gender influence was found for astigmatism or malocclusion.
  
  
  CONCLUSIONS
  Few study investigated a possible relationship between the ocular and stomatognathic system, and no data are available in the scientific literature. A higher prevalence of astigmatism was found in patients with cross-bite: as expected no other significant association was found. The relationship between astigmatism and cross-bite could be either related to a specific skeletal pattern, which could induce visual alterations, or to the effect of abnormal visual input on the postural system, which could induce stomatognathic alterations.
  
  
  CONCLUSIONS
  The findings of the present study suggest a possible association between astigmatism and cross-bite, but future studies are needed to confirm and explain this observation.
authors.affiliation: Department of Gnathology, School of Dentistry, University of L'Aquila, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Monaco
authors.forename: A
authors.initials: A
authors.lastname: Spadaro
authors.forename: F
authors.initials: F
authors.lastname: Sgolastra
authors.forename: A
authors.initials: A
authors.lastname: Petrucci
authors.forename: P D
authors.initials: PD
authors.lastname: D'Andrea
authors.forename: R
authors.initials: R
authors.lastname: Gatto
mesh_terms: D000293:Adolescent; D001251:Astigmatism / Q000453:epidemiology*; D002508:Cephalometry; D002648:Child; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008310:Malocclusion / Q000453:epidemiology*; D008311:Malocclusion, Angle Class I / Q000453:epidemiology; D008312:Malocclusion, Angle Class II / Q000453:epidemiology; D008313:Malocclusion, Angle Class III / Q000453:epidemiology; D003765:Models, Dental; D015995:Prevalence; D011862:Radiography, Panoramic; D012737:Sex Factors