title: Interpupillary index: a new parameter for hypo-hypertelorism.
abstract: OBJECTIVE
  To establish a new clinical index to evaluate the presence of hypo-hypertelorism with greater accuracy.
  
  
  METHODS
  After screening a wide range of population, 310 elementary school children (185 boys, 125 girls) aged 7-15 years were included in this study. For this cross-sectional study, a millimetre ruler was used. The anatomical interpupillary distance was measured by a modified Viktorin's method. In addition, inner and outer intercanthal distances were obtained. The data were analyzed by Student's t-test for two independent samples using SPSS for Windows. There were children with clinical hypertelorism (n = 92, group 1), children with large fronto-occipital circumference (FOC) (n = 101, group 2), and age- and sex-matched normal controls (n = 117, group 3). Due to variations in FOC among healthy subjects, we introduced a new practical concept for evaluation of interpupillary distance, namely the interpupillary index, the simple product obtained by dividing the interpupillary distance by the FOC, multiplied by 100.
  
  
  RESULTS
  The overall idiopathic benign macrocephalic children (group 2) had significantly (p < 0.001) larger interpupillary distances (6.13 +/- 0.36 cm) and FOCs (56.99 +/- 1.46 cm) than those of normal controls (5.70 +/- 0.26cm and 52.82 +/- 1.22 cm, respectively). But, the difference between the combined product of interpupillary distance and FOC, the interpupillary index, was not significant (10.76 +/- 0.50 and 10.79 +/- 0.35, respectively) (p > 0.05). On the other hand, the children with hypertelorism had significantly (p < 0.001) larger interpupillary distances (6.47 +/- 0.29cm) and FOCs (54.90 +/- 2.18cm) when compared with the controls. In addition, the interpupillary index was significantly (p < 0.001) higher (11.80 +/- 0.45) than both macrocephalic children (10.76 +/- 0.50) and controls (10.79 +/- 0.35). Intercanthal distances and intercanthal index of hyperteloric children were also significantly (p<0.001) larger than both macrocephalic children and controls.
  
  
  CONCLUSIONS
  This new index offers a new concept for more accurate evaluation of the presence of ocular hypo-hypertelorism.
authors.affiliation: Department of Ophthalmology, Inönü University Medical Faculty, Turgut Ozal Medical Centre, Research Hospital, Turkey. evereklioglu@hotmail.com
authors.forename: C
authors.initials: C
authors.lastname: Evereklioglu
authors.forename: S
authors.initials: S
authors.lastname: Doganay
authors.forename: H
authors.initials: H
authors.lastname: Er
authors.forename: M
authors.initials: M
authors.lastname: Tercan
authors.forename: A
authors.initials: A
authors.lastname: Gunduz
authors.forename: A
authors.initials: A
authors.lastname: Balat
authors.forename: M
authors.initials: M
authors.lastname: Borazan
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002508:Cephalometry / Q000592:standards*; D002648:Child; D005123:Eye / Q000033:anatomy & histology; D005546:Forehead / Q000033:anatomy & histology; D006801:Humans; D006972:Hypertelorism / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D012016:Reference Values; D012886:Skull / Q000033:anatomy & histology