Assessing chromatic discrimination in women on hormonal contraceptives.

We explored whether chromatic discrimination is affected in women using hormonal contraceptives (HCs). Leaning upon earlier studies of oral contraceptives (OCs), we reasoned that estrogen and/or progestin, HC components, would reveal mild tritan-like defects in HC users. A sample of 68 women (18-45 years) was stratified by the HC type and use history: (a) non-users with past HC use (PC=21), (b) never used (NC=16), (c) oral contraceptives (OCs=23), and (d) long-acting reversible contraceptives (LARCs=8). Employed was the Cambridge Colour Test (CCT), along with screening using the D-15 and D-15d tests. Significant inter-group differences were identified by the CCT Trivector measures and D-15d indices. Specifically, the majority of LARC users revealed higher tritan and/or protan and deutan thresholds. The D-15d indices were comparable for users of modern OCs and NC but were higher in the LARC and PC groups. Conceivably, the long-acting progestin in LARC users down-regulates the expression of retinal estrogen receptors implicated in color discrimination.