Growth Pattern and Use of Inter-pupillary Distance in the Detection of Ocular Hypertelorism and Hypotelorism in Indian Down Syndrome Children.

Use of inter-pupillary distance (IPD) for objective evaluation of ocular hypertelorism and hypotelorism is recommended to corroborate diagnosis of syndromic conditions. In view of complete absence of serial data on growth of IPD, this study aims to unfold auxological dynamics of IPD in Down syndrome (DS) children of Indian origin. Inner canthal distance (ICD) and outer canthal distance (OCD) were measured on a total of 1,125 (male: 752, female: 373) DS children, aged 0 to 3 months to 10 years at 6 monthly age intervals using a "Digimatic Sliding Caliper" in the Growth Laboratory/Growth Clinic of the Institute. Using Feingold and Bossert (1974) formula, IPD at each age was calculated from ICD and OCD measured among male and female DS children. IPD, like OCD and ICD increased un-interruptedly among DS children. IPD grew rapidly up to 5 years thereafter, its rapidity became slower. Boys in general, possessed larger IPD than girls, however, gender differences became statistically significant up to first 4 years of life. Our study children possessed significantly smaller IPD as compared with their normal Indian counterparts. None of our DS children depicted ocular hypertelorism while hypotelorism, was noticed amongst 4.9% male and 16.8% female DS patients. Comparison with normative IPD data failed to establish existence of ocular hypertelorism in DS children (<10 years) of north-western Indian origin. Use of age and gender-specific data presented for IPD of DS children may be made for comparative purpose to ascertain inter-population variability.