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Evgenia Konstantakopoulou, Marisa Rodriguez-Carmona, John L. Barbur; Assessment of Chromatic Sensitivity in Female Carriers of Colour Vision Deficiency. Invest. Ophthalmol. Vis. Sci. 2011;52(14):4901.
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In spite of numerous studies, colour vision in female carriers remains controversial with some studies reporting improvement and others a worsening of red/green (RG) chromatic sensitivity. The purpose of this study is to investigate the extent to which the additional photopigment that can be expressed in female carries of colour deficiency affects their RG chromatic sensitivity.
30 heterozygote females were examined, aged 23 - 73 years of age. RG and yellow/blue (YB) chromatic sensitivity was measured using the Colour Assessment Diagnosis (CAD) test. Four background light adaptation levels (i.e., 65, 26, 7.8 and 2.6 cd/m2) were employed and measurement of pupil size at each level provided an average measure of retinal illuminance. The optical density of the crystalline lens (i.e., ODL for the shot wavelength region) and the macular pigment optical density (MPOD) were measured using the Macular Assessment Profile (MAP) test. 41 male subjects (age range 23 to 71 yrs) were used as controls.
The carriers were divided into four groups: carriers of deuteranomaly (DA), deuteranopia (D), protanomaly (PA) and protanopia (P). The measured YB thresholds in all carriers were not significantly different to the male control group (p=0.31). Carriers of DA and D showed lower RG chromatic sensitivity than normal trichromats (p0.05), whereas carriers of PA or P showed similar RG sensitivity to controls (p>0.05).
Differences in RG colour vision between controls and P and PA carriers are not statistically significant. This is not the case for D and DA carriers which show significantly reduced RG chromatic sensitivity. The results suggest that a relative increase in the number of LL’ cones in the retina, as expected in the D and DA groups can cause a significant worsening of RG colour vision, whist an increase in the number of M/M’ cones, as expected in the P and PA groups, does not cause a significant decrease in RG sensitivity.
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