Yubraj Neupane, B. Optom Student

Acharya Institute of Allied Health Sciences, Bengaluru, India



Optical Illusion is also known as the illusion of the visual system. It is caused by the misinterpretation of the brain. It happens when our eyes see the object and sends the signal to the brain, which perceive the image something different on reality.(1)

What is Optical Illusion?

Optical Illusion distorts the perception of the visual system. Basically, the optical illusion is composed of light, colour and the pattern which misguide our brain to perceive the image of the object.(2) The main purpose of the optical illusion, according to the experts, is mainly to help us make our brain sharper. Most of the illusion are so hard to understand that, how the thing or art is possible.(3)

Types of Optical Illusion:

1. Geometric Illusion: The object differs by the shape, size, and pattern of the object. It is designed in different shapes to manipulate the perception of the viewers. It is occurred by the

Figure 1: Example of geometric illusion

mismatch of the seen object often by giving misroute guidance during the neural processing in retina (Figure 1).(4)

2. Ambiguous Illusion:

Ambiguous illusions are popular and mostly used in recent days. It illustrates the multiple images. Ambiguous illusion is unclear or it might confuse because the image can be taken in multiple ways. It is also known as the reversible figures formed by the visual systems.[5]

Figure 2: Example of ambiguous illusion

3. Colour illusion:

The trichromatic theory explains that colour vision results from the relative intensity of response of cones. It is the phenomenon of superimposing colour signals in the brain by the signal carrier. The illusion of the colour can be seen even if the patient is having a colour blindness (Figure 3).(6)

Figure 3: Example of colour illusion

The Science behind Optical Illusion:

The illusion happens when there is a gap of communication. In a simple word, the relation between the eye and the brain does not have a proper interaction about the object. So, the image gets mixed-up. Most of the Scientists and Psychologists found that the pattern of the object is complex and tricky that eye plays with our brain. It relates on how our subconscious mind interpret one object with another.(7)

The Brain’s Role in Deception:

Our brain plays an important role in creating the illusion. This illusion is created by the visual cortex. Real life applications of the optical illusion are moon illusion and traffic planning. Optical illusion works as a powerful tool and it helps in attracting the attention of the people, illustrate the product and brand.(8)

Enjoyment and Educational Value:

Optical Illusions teaches and trains us about how our brain and the eye work together to recognize the lights, depth, shading, and position to see the things. The objects are so challenging and studying the visual illusion lead in understanding of neural mechanism to process the information.(9)


The optical illusion creates the wrong understanding of the object, and which misguides the brain to understand the object. This illusion occurs due to complexities of objects and thus can increase as objects range and function of quality or variety of materials and by surface style.



  1. Carbon C. C. (2014). Understanding human perception by human-made illusions. Frontiers in human neuroscience, 8, 566. https://doi.org/10.3389/fnhum.2014.00566
  2. Pinna, B., Porcheddu, D., & Skilters, J. (2022). From perceptual organization to visual illusions and back. Frontiers in human neuroscience, 16, 960542. https://doi.org/10.3389/fnhum.2022.960542
  3. Gori, S., Molteni, M., & Facoetti, A. (2016). Visual Illusions: An Interesting Tool to Investigate Developmental Dyslexia and Autism Spectrum Disorder. Frontiers in human neuroscience, 10, 175. https://doi.org/10.3389/fnhum.2016.00175
  4. Wade, N. J., Todorović, D., Phillips, D., & Lingelbach, B. (2017). Johann Joseph on Geometrical-Optical Illusions: A Translation and Commentary. i-Perception, 8(3), 2041669517712724. https://doi.org/10.1177/2041669517712724
  5. Mast, F.W.; Kosslyn, S.M. (2002). “Visual mental images can be ambiguous: Insights from individual differences in spatial transformation abilities”. Cognition. 86 (1): 57–70. doi:10.1016/S0010-0277(02)00137-3. PMID 12208651. S2CID 37046301.
  6. Pinna, Baingio, Daniele Porcheddu, and Katia Deiana. 2018. “Illusion and Illusoriness of Color and Coloration” Journal of Imaging 4, no. 2: 30. https://doi.org/10.3390/jimaging4020030
  7. Çengel Y. A. (2023). A Concise Account of Information as Meaning Ascribed to Symbols and Its Association with Conscious Mind. Entropy (Basel, Switzerland), 25(1), 177. https://doi.org/10.3390/e25010177
  8. Bohrn, I., Carbon, C. C., and Hutzler, F. (2010). Mona Lisa’s smile—perception or deception? Psychol. Sci. 21, 378–380. doi: 10.1177/0956797610362192
  9. Abdlfatah, R. F., Alomaier, A. T., Ahmad, A. S., Elmahal, D. M., & Ibrahim, D. M. (2022). V-EduGram: Voice-based control technique of hologram technology in education. Proceedings of the 2022 2nd International Conference on Computing and Information Technology (ICCIT), 230-236. IEEE.