SCHEINER’S DISC EXPERIMENT * - Copy.pptx

Scheiner's Disc Experiment: Unveiling the Mysteries of the Eye and Vision
In the early 17th century, German Jesuit priest and scientist Christoph Scheiner conducted a groundbreaking experiment that revolutionized our understanding of human vision and the eye. Scheiner's Disc Experiment, as it came to be known, was a pioneering study that delved into the intricacies of perception, challenging prevailing beliefs and paving the way for future scientific discoveries.
Background and Context
During the Renaissance, the scientific community was abuzz with curiosity about the human body and its functions. The eye, in particular, was an enigma, with many theories attempting to explain its workings. Scheiner, an accomplished astronomer and mathematician, sought to unravel the mysteries of vision through experimentation.
The Experiment
Scheiner's Disc Experiment consisted of a simple yet ingenious setup:
The Disc: A circular disc with a small hole in its center was created. The disc was painted with a uniform color, and the hole was carefully crafted to be smaller than the pupil of the human eye.
The Observation: A subject was asked to look through the hole in the disc, focusing on a distant object. The disc was then slowly moved closer to the subject's eye while maintaining focus on the object.
The Observation Point: The subject was instructed to indicate when the object appeared to change shape or distort.
Findings and Implications
Scheiner's experiment yielded remarkable results:
Persistence of Vision: The subject reported that the object appeared to maintain its shape even when the disc was moved closer, demonstrating the persistence of vision.
Inversion of the Retinal Image: Scheiner observed that the image formed on the retina was inverted, contradicting the prevailing belief that the eye saw the world in its correct orientation.
The Eye's Role in Perception: The experiment highlighted the eye's role in processing visual information, rather than simply acting as a passive receiver of light.
Impact and Legacy
Scheiner's Disc Experiment had far-reaching consequences:
Challenging Aristotelian Views: The experiment challenged the long-held Aristotelian belief that the eye saw the world in its correct orientation, paving the way for modern understanding of vision.
Laying the Foundation for Modern Optics: Scheiner's work influenced prominent scientists like René Descartes and Isaac Newton, shaping the development of modern optics.
Advancements in Ophthalmology: The experiment's findings contributed significantly to the understanding of the human eye and its functions, driving progress in ophthalmology.
Conclusion
Scheiner's Disc Experiment stands as a testament to the power of scientific inquiry and experimentation. By challenging prevailing beliefs and pushing the boundaries of human knowledge, Scheiner's work has had a lasting impact on our understanding of vision, the eye, and the intricacies of perception.This pioneering experiment continues to inspire.

1. SCHEINER’S DISC EXPERIMENT By R.Shalini BSc.Optometry-2 nd year VISM

2. INTRODUCTION IN 1612, Christoph Scheiner discovered a fundamental principle of binocular vision using a simple disc with two holes. This experiment demonstrates how our brain processes visual information from both eyes. IMPORTANCE Crucial for understanding binocular vision and neural processing of visual informations.

3. Scheiner’s Disc Experiment

4. SETUP A circular disc with two small holes A light source or object to view through the holes. PROCEDURE Circular disc is placed in front of patient with two holes pointed at the centre of pupil. Look through both holes at same time, focusing on the light source or object. Slowly rotate the disc . See how the images from each eye switch back and forth.

5. BINOCULAR VISION The ability to see the same image with both eyes. Brain combines image from both eyes. RETINAL RIVALRY When images from each eye are different. Brain struggles to combine images.

6. IMAGES FORMED IN DIFFERENT REFRACTIVE ERRORS IN EMMETROPIC EYE: In these parallel rays of light from a distant object through the disc hole focuses on retina . Scheiner’s disc image: single , clear circle . IN MYOPIA: In these, parallel rays of light from a distant object through the disc hole crosses and focuses in front of retina . Scheiner’s disc image: two overlapping circles ,with one circle larger than the other.

7. IN HYPEROPIA: In these, parallel rays of light from distant object through the disc hole focuses behind the retina . Scheiner’s disc image: two overlapping circles with with one circle smaller than the other. IN ASTIGMATISM: Light rays focus at two different points . Scheiner’s disc image: two overlapping ellipses .

8. AUTOREFRACTOMETER WORKING PRINCIPLE Autorefractometer projects a light beam into eye through a rotating disc. The refracted light forms an image on retina. The rotating disc creates a situation where the images from each eye are slightly different due to refractive error. Autorefractometer measures the movement of retinal image . Then calculates the refractive error based on the movement and provides a lens prescription. Autorefractometer works on the principle of scheiner’s disc.

9. CHANGES IN THE LENS DURING ACCOMODATION

10. RELAXED STATE Lens is thin and flat. Tension in zonules. Lower refractive power of lens

11. ACCOMODATED STATE Ciliary muscle contract. Zonules relax Lens become more spherical. High refractive power of lens.

12. CHANGES IN LENS Increase in lens thickness Increase in lens curvature Increase in lens diameter. Lens become more spherical.