Sometimes you see something that makes you take a second look. Yesterday it was these beautiful clouds that swept across our northern horizon, with an occassional electrical explosion punctuating their inkiness. Magnificent! And the contrast of the sun on the kale, broccoli and silverbeet - ahh, beautiful!
Have you ever been consciously thankful for the cone photoreceptors in your eyes that allow you to see colour? A normal eye has around 6 million of these champions, mostly located at the centre of the retina, who provide both our detailed vision and the colour vision that makes our life, well, beautiful.
People who have achromatopsia either have few cones, or totaly lack them. Those with complete achromatopsia must rely entirely for sight on their about 100 million rod photoreceptors who are located mostly at the periphery of the retina, and who do not provide the color vision or good detail vision of the cones. Thus they are totally colorblind and have poor visual acuity - they can see no colour at all, and their world consists of different shades of blury grey ranging from black to white, rather like only seeing the world on an old black and white television set.
Thank God for colours, and for cones to see them with!