The Rod Cells and Cone Cells are both photoreceptor cells present in the eyes. These are sensitive receptors responsible for making vision possible altogether. They simply convert the light entering the retina into signals, and these signals are very potent as they change the complete membrane potential and enables the eyes to see. The resultant is called visual photo transduction. Therefore, the sole aim of these Rod and Cone Cells is to help the eyes fulfil their basic need, help it recognize the light waves, and convert them to signals which makes vision possible in humans and animals. The major difference between Rod Cells and Cone Cells is that the former enables one to watch in low light and the latter helps in the vision in bright light.
|Rod Cells||Cone Cells|
|Sensitivity||Rod Cells are very sensitive to low light.||Cone Cells are very sensitive to bright light.|
|Structure||Rod Cells are narrower than the Cone Cells.||The Cone Cells are wider than the Rod Cells.|
|Location||The Rod Cells are located at a very peripheral location in the retina.||The Cone Cells are situated at the central location, which is also known as the fovea or the retina.|
|Quantity||The normal human eyes have more number of Rod Cells.||The number of Cone Cells is always less than that of the Rod Cells.|
|Contents||The Rod Cells contain only a single type of visual pigment.||The Cone Cells have three different kinds of visual pigments present in them.|
The Rod Cells are cylindrical shaped. These are photoreceptor cells present at the peripheral part of the retina which absorbs light in the form of photons and converts it to the signals which can be comprehended by the retina. There are about 120 million Rod Cells present in the eyes which make vision possible in the extremely low light as the Rod Cells are triggered by even the faintest of the light rays. These Rod Cells are very narrow in comparison to the Cone Cells, but at the same time, they are much more sensitive to light rays. This is the reason why they help us to see even in the very low light.
The Cone Cells are a bit shorter photoreceptor cells which are located at the central part of the retina which is also called the fovea. The Cone Cells are present in a very less number in the retina, somewhat around 6 million cells and they are not very sensitive to light. They need the very high amount of light to trigger them and get into action. As they are sensitive to large quantities of light, the Cone Cells help in making the vision in bright light possible.
So, Rod Cells and Cone Cells are both photoreceptors but have certain huge differences. But at the same time, it cannot be denied that while the loss of Rod Cells can cause night blindness, the loss of Cone Cells will lead to permanent blindness.