I’m using my camera to try and understand how macular degeneration is affecting Dad’s vision. He can see the tree in the distance but his colour perception is dulled. Why?
Rods and Cones
The macula is in the centre of the retina which is the light-sensitive layer of tissue at the back of the eye. Light enters the iris and reacts with photoreceptors of the retina which send messages, through the optical nerve, to the brain. There, visual information is processed so we can relate it to the environment we are in.
There are two types of photoreceptors – rods and cones, named after their shape. Rods exist in far greater numbers in the eye and are mainly located around the boundary of the retina. These help us with low light vision. Cones are fewer in number and exist in the centre of the retina. They assist us with colour definition.
With damage to the central portion of his macula, I’m beginning to understand why what dad sees appears dull. There is a decrease in functioning of the cones. (I have intentionally desaturated the above image to try and see as he does).
Dad explains how he looks into a device so the Ophthalmologist can take images of the inside of his eyes. I’d like to take a closeup of his eyes but have not brought my macro lens with me on this trip. So dad’s eyes are inadequate for the task and my camera equipment is too.
This is part two of my subseries ‘What do you see Dad?
I’m in South Africa with my elderly parents for a time, my fourth visit in two years. I meld into their routine and help where I can, always trying to preserve their dignity. Their perception of life is determined by past experience, values and the current ravages of deteriorating health. My lens is recording as respectfully as possible their reality. This is a sub part of a project Plot148, not yet complete.