Abstract
Abstract: :
Purpose: It has been demonstrated that melanocytic number in brown, hazel and blue irides is approximately equal. No studies have previously been carried out comparing melanocytic number in brown irides of African-Americans, Asians and Caucasians. The purpose of the present study was to compare the number of melanocytes present in brown irides in Asian, African-American and Caucasian ethnic groups, using immunohistochemical staining of stromal melanocytes under fluorescence microscopy. Method: Paraffin - embedded sections from 71 dark brown colored human irides were incubated with rabbit anti-cow antibody against S100a, linked with an FITC conjugate antibody, and counterstained with Evans Blue. Cells were counted under a fluorescent microscope and scored as melanocytes or fibroblasts and clump cells. Cell number and proportions of melanocytes were determined for each iris. Results: Irides from Asian adults (N=16) had fewer melanocytes than irides from African-American adults (N=44) (p = 0.005) and from Caucasian adults (N=11) (p = 0.001) and fewer total cells than African-American (p = 0.005) or Caucasian (p = 0009) eyes. The proportion of melanocytes relative to fibroblasts and clump cells was not significantly different between the groups (p = 0.21). Conclusion: No difference was observed between the number of melanocytes in Caucasian and African-American irides. No difference was observed in the proportion of melanocytes relative to fibroblasts and clump cells across the ethnic groups. Irides from Asian adults had fewer melanocytes, fibroblasts and clump cells than irides from African-American and Caucasian adults. Mean (SD) by ethnic group
Keywords: 447 iris • 463 melanocytes • 434 immunohistochemistry