In this study, scientists looked into the causes of Startgardt-like macular dystrophy. This disease badly affects the cell membranes of light-receptive cones in the eyes, which are used to see color in daylight. The odd thing is the disease doesn’t affect nearly identical membranes in rod cells, which are used for night vision. By comparing rods and cones between daytime living (diurnal) and nightime living (nocturnal) rodents, they discovered that rod membranes have more Omega 3 fatty acids. The researchers believe this chemical difference protects the rods from Startgardt-like macular dystrophy.
- Ocular cells responsible for light sensitivity consists of two types: rods and cones. Nocturnal animals have a higher rod cell concentration; diurnal animals have a higher cone cell concentration.
- The eyes of diurnal animals is more like the human eye, making them more suitable to study human eye disease such as genetic mutation affecting cone cells that causes Startgardt-like macular dystrophy
- PUFAs transmit ocular signals. Research using diurnal lab mice show PUFAs differ between rod and cone cells. PUFAs used by cone cells are affected by the genetic mutation but don’t affect rod cells.
“This suggests that perhaps different lipids are important for signaling in cone receptors than in rod receptors and may explain why rod cells, which have higher PUFA levels, are not affected by mutation to PUFA synthesis genes.”