Thyroid affects colour vision
Thyroid hormone controls the eye´s visual pigments throughout life
What part does the thyroid gland have in vision? Thyroid hormone is crucially involved in controlling which visual pigment is produced in the cones. Previously, it was assumed that the colour sensitivity of the cones is fixed in the adult retina. Researchers at the Max Planck Institute for Brain Research in Frankfurt/M., together with colleagues at the University of Frankfurt and universities in Vienna, have now been able to show that in mature cones of mice and rats the production of visual pigment is regulated by thyroid hormone. It is assumed that this mechanism exists in all mammals, including humans. If so, the adult-onset of thyroid hormone deficiency would affect colour vision.
Fluorescence micrographs of the cone cells in the retina of an adult healthy rat (top) and of an adult rat with thyroid hormone deficiency (bottom). The cones were labelled with antibodies against their opsins; green opsin is shown in green and UV/blue opsin in magenta. The healthy rat has many green cones and few UV/blue cones. The rat with thyroid hormone deficiency expresses UV/blue opsin in all cones and reduces expression of green opsin. Appearing in lighter magenta in the bottom image are cones that contain some green opsin in addition to the dominant UV/blue opsin. © Martin Glösmann