13 Important Difference between Rods and Cones

What is the difference between rods and cones with respect to color vision?

Well, read through the article step by step and get to know the differences.

Meanwhile, eyes are essential sense organs in the animal kingdom. The core aim of the eyes is to visualize the object coming in front of us.

The main task of forming an image on the retina is done by rods and cones also known as photoreceptors. These photoreceptors absorb the light and convert into signals that trigger the membrane potential to visualize.

However, there are a lot of factors that make rods and cones to be different. Let’s jump into the information and find out rod cells vs cone cells.

Difference between Rods and Cones

What Are Rods?

Rods are photoreceptor cells that support vision during dim light or at night. They are usually located at the periphery of the eye and they occur in plenty amount.

Rhodopsin is the main pigment found in the rods and it is responsible for the night vision. Rods are said to be light sensitive.

Rod cells are also said to have a scotopic vision which implies that they perform well during dim light or at night. People with a low amount of rods usually experience night blindness. 

What Are Cones?

Cones are photoreceptor cells that support vision during the day or bright light vision. These cone cells are a small amount when compared to rods.

The good news about cones is that an individual is able to differentiate between colors. Therefore, cones occur in three forms such as green, blue, and red. They are also less sensitive to light.

Iodopsin is the violet pigment presence in cones and it is responsible for violet vision. Cones tend to experience photopic which means eyes are able to visualize under bright light.

People with a low amount of cones normally experience colorblindness. Hence they are unable to differentiate between colors. 

Comparison Chart: Rods Vs Cones

Here is the difference between rods and cones in tabular form. Let’s find out more:

Rods Cones
Are photoreceptors responsible for vision during dim light or at night time? Are photoreceptors responsible for vision during day time or bright light vision?
Are located at the periphery of the retina in an ample amount. Are located at the center of the retina but in a low amount.
Human eyes have about 125 million rods. Human eyes have about 5 million cones
Has rhodopsin as a photosynthetic pigment Has iodopsin as a photosynthetic pigment
Has one color vision which is black and white Has several color visions like red, green and blue
Speed of response to light is quite slow Speed of response to light is quite fast
Light level is scotopic Light level is photopic
Has cylindrical shape Has conical shape
Visual acuity is low since they share neurons with the brain Visual acuity is high since each cell has its own neuron.
Deficiency is rods causes night blindness Deficiency in cones causes color blindness
Quite sensitive to scattered and direct light Quite sensitive to direct light only
Narrower in shape Wider in shape
Absent in fovea Concentrated in fovea

Core Differences between Rods and Cones In Point Form 

  1. Rods are responsible for vision in dim or night light while cones are responsible for vision in bright or daylight.
  2. Rods are located around the periphery of the retina whereas cones are located at the center of the retina.
  3. Cones have conical shapes while rods have a cylindrical shape.
  4. Rods are quite sensitive to scattered and direct light while cones are quite sensitive to direct light only.
  5. Rod cells tend to be narrower while cone cells are wider on the other hand.
  6. Human eyes have plenty of rod cells as compared to cone cells.
  7. Rod cells with deficiency rhodopsin cause night blindness while cone cells with insufficient iodopsin cause color blindness.
  8. Cone cells provide color vision in the form of red, green, and blue while rod cells do not provide any color vision apart from black and white.
  9. Rod cells have higher regenerative power as compared to cone cells.
  10. Rods occur in an ample amount while cones in less amount since they perform different duties.

Similarities between Rods and Cones

  1. Both are photoreceptor cells
  2. Both absorb light at a different wavelength
  3. Both are modified nerve cells
  4. Both are synapse with bipolar cells
  5. Both experience phototransduction

Frequently Asked Questions

  • Why Are Rods More Sensitive than Cones?

Rods require less light to function than cones. Therefore, they are about 100 times more sensitive to a single photon than cones.

  • Do We Have More Rods or Cones?

Rods are more than cones on the retina. There are about  120 million rods on the retina which makes them more sensitive than cones. 

  • How Do Rods and Cones Work?

Rods work at a very low light hence suitable for night vision. Cones work at a very high light hence suitable for day time vision. Cones can be used to see more colors. 

  • Do Cones See Color?

Absolutely. The cones tend to use a lot of light and help in distinguishing different colors. Cones are divided into blue, green, and red. The human eye has about 6 million cones for color and daytime vision. 

  • Can Rods and Cones Regenerate If Damaged?

Before the retina cells die, rods and cones can be regenerated. But in case of nerve damage, the eye photoreceptors, rods and cones will not regenerate. 

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Comparison Video

Conclusion

Both rods and cones in the eye perform different tasks besides both of them being photoreceptors. The rods and cones diagram above helps to clarify their location in the human or animal eye.

I hope the information listed above will be helpful during your study. If you have anything to share or add on kindly use the comment section below.

More Sources and References

  1. Rods and Cones of the Human Eye. Ask Biologist

  2. Rods and Cones. Hyperphysical 

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