Another important aspect of lighting a space for those with diminishing eyesight is visual cuing. Visual cuing provides an additional reference point for judging distance or depth when entering a space or approaching objects. The lighting at the base of these cabinets or toe-kick lighting contrasts well with the dark floor and midtone cabinetry creating a readily visible contrast. But people will just think it's cool.
When hanging a light over a table or a kitchen island 28 to 34 inches is the recommended distance from the bottom of the light to the surface of the table or island. However the size of the light makes a difference. In general a smaller light can be moved lower and a larger light can be moved higher.
Bright idea for dimmed lighting: To make the most of your lighting install the highest-wattage lightbulb possible then dim it down to accommodate the mood and lighting needs. Consider putting dimmers on both overhead lighting and lamp lighting.