[Low prevalence of dyschromatopsia using the fourth edition of HRR (Hardy, Rand and Rittler) pseudoisochromatic plate test among the Indian population of Lalima village, Terena].
OBJECTIVE
to evaluate the frequency of dyschromatopsias among the 10 to 45-year-old male Indian population of Lalima village, Terena ethnicity, in Miranda-MS, using the fourth edition of the pseudoisochromatic HRR test (Hardy, Rand and Rittler).


METHODS
Lalima village in Miranda-MS was visited in January and February 2005. The visits only occurred after the approval of the project by the Committee of Ethics and Research of UFMS, by the National Committee of Ethics and Research, by the Indian National Foundation, and by the chief of Lalima village. The test was applied in 226 Indians who had been previously submitted to ophthalmologic examination for the detection of abnormalities that could doubt the applicability of the test. The test was performed under natural illumination, in sunny days, however with no direct sunlight. The test was applied and analyzed by the same experimenter in all the Indians.


RESULTS
Two hundred and twenty-six men were examined (60.1%) of the total male population of 376 individuals between 10 and 45 years old who live in Lalima village. No cases of dyschromatopsia were found in this population examined with the HRR test.


CONCLUSIONS
Once it is known that incidence of dyschromatopsias among the white male Caucasian population is about 6-8%, the results of the present study indicate a low prevalence of dyschromatopsias in this Indian population of Terena ethnicity, since no cases were detected in the examined sample. Other studies using different methods must be made to reinforce the present results. It would also be interesting to genetically examine this population and verify the genes that code for photopigments.
Piccinin
Marcos Rogério Mistro
MR
Universidade de Brasília, Brasil. mrpiccinin@yahoo.com.br
Cunha
Juliana Ferrari
JF
de Almeida
Herbert Paulo
HP
Bach
Cleiton Cassio
CC
de Oliveira Dossa
Andréa Cristina Grubits Gonçalves
AC
da Silva
Reinaldo Ferreira
RF
Pessoa
Valdir Filgueiras
VF
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001938:Brazil / Q000453:epidemiology; D002648:Child; D003119:Color Perception Tests / Q000379:methods*; D003117:Color Vision Defects / Q000175:diagnosis / Q000453:epidemiology* / Q000208:ethnology; D006801:Humans; D007199:Indians, South American; D008029:Lighting; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D015995:Prevalence; D015203:Reproducibility of Results