I was just reading the book 'Medical Herbalism' by David Hoffman, kindly lent to me by Naturopath Natasa Zaric. 

"Hypothyroidism accelerates the development of atherosclerosis, due to deposition of mucopolysaccharides in the heart muscle, placing patients at higher risk of heart disease'. D. Hoffman

This information supports the link between the lymphatic rosary (mucopolysaccharides) and the thyroid. Mucopolysaccharides are long chains of sugar molecules that are found throughout the body, often in mucus and in fluid around the joints.

The ring of harmony is said to be formed from mucopolysaccharides and in Rayid Iridology this ring is linked to the immune system, lymphatic system, tonsils and thyroid gland. 

Often the lymphatic rosary will be most prominent at 9-10 o'clock in the right eye and 2-3 o clock in the left eye- these areas are near the heart zones of the eye. Hence those with lymphatic beads in these areas may need heart support with herbs such as hawthorn which is a vascular tonic, which may help clear plaque from arterial blood vessels. 
Plus of course we need to address the cause,  the low thyroid and resulting plaque build up as indicated by the lymphatic beads in the iris.

Thanks to David Hoffman for another piece of the puzzle !