Tag: eye

The Earliest Discovered Sewing Tools for Surgery and Textiles

Leave a comment

The earliest discovered eyed needles designed for surgery are from 30,000 B.C. This specific artifact was discovered within a cave located in Aurignacia, France. Additionally, other ancient needles have been uncovered within the region of Altai Krai, Russia, specialist needles without an eye but with a split head designed to grip the thread. These tools which are crafted from bird bone by the Denisovans, date back to 40,000 B.C. – 30,000 B.C. Both discoveries indicate that early human beings had developed sophisticated tools and techniques for sewing, tools which could have been used for many tasks ranging from textile repairs to complex tasks like surgery

Galileo Galilei’s Telescope Design Improvement Upon the Dutch Spyglass Design

1 Comment

It had been known since the first spectacles were produced in the middle of the 13th century, that glass was capable of bending light, a property which no other known material of the period could achieve. The Dutch spyglass worked upon this very principal, arranging lenses with careful attention to detail to create a compounding magnification effect. If light hits a plano-convex (pronounced “play-noh”) lens, which is flat upon one side and convex upon the other, the same formation used for those who suffer from hyperopia, rays of light streaming inward are bent toward eachother, eventually meeting and converging at a specific triangular point. Right before this focal point, Galilei improved the original Dutch design by placing his second lens, an ocular lens which is plano-concave, meaning flat upon one side and concave upon the other, the same formation used for those who suffer from myopia. This secondary lens pushes the bent rays of converging light back out again so that they can hit the eye and provide a clear image. The eye focuses this light upon the retina so that the observer can view the image produced by the spyglass. The magnification power of a telescope depends upon the ratio between the focal lengths of the lenses, with these distances marked as F1 for the distance between the front of the spyglass and the plano-concave lens, and F2 from the plano-concave lens toward the back of the spyglass. The largest difficulty impeding Galilei was the grinding down process of his convex lens, in an attempt to make it as shallow as possible to maximize the length of the F1 partition, as the longer the distance is, the greater the magnification will be. Within a few weeks of developing this new technology, Galilei’s first telescope had a clear magnification of 8x, far exceeding the power of the original Dutch spyglass. On August 21, 1609, Galilei climbed a Venice bell tower to meet up with Venetian nobles and senators so that he could display his new technology. This new bleeding edge feat of engineering permitted Venetians to spot sailing ships 2 hours earlier than if they had used the naked eye. 3 days after the event, Galilei gifted his telescope to the Duke of Venice and was afforded a guaranteed job for life in exchange, with this salary equating to double his original income. With his finances secured, Galilei went on to develop and produce even more powerful telescopes

The Causation and Cure for Colorblindness

Leave a comment

Being colorblind is more difficult than most people believe as those affected often cannot match clothing colors, tell when fruit is ripe, tell when meat is cooked, or tell when traffic lights are various colors in certain lighting conditions (e.g. flashing red being mistaken for flashing yellow). Color vision is trichromatic with 3 types of cone cells within the eyes which consist of blue, green, and red, which are sensitive to short, medium, and long wavelengths of light, with each cone permitting an observer to view approximately 100 different shades. When all shades are combined, the human eye can observe approximately 1,000,000 (1 million) different colors. Colorblindness can stem from faulty cone cells or an interruption between the pathway of the cones and the brain. Colorblindness has caused vehicular deaths due to accidents around the world which have occurred most often because a driver perceived a light as yellow when it was red in reality. Neuroscientist Professor Jay Neitz (pronounced “nites”), a color researcher at the University of Washington in the U.S. and his spouse, geneticist Maureen Neitz, have teamed up to try and cure colorblindness. Gene therapy is currently being researched around the world and scientists believe that colorblindness will be cured using gene therapy in the near future. Male squirrel monkeys are naturally red-green colorblind and gene studies have demonstrated that these monkeys can be afforded color vision after having a gene delivered into the cone cells within the eye. The gene produced transforms a subset of the green cones within the male squirrel monkeys eyes to force them to become red cones, red cones which have hijacked the squirrel monkeys neural circuitry which was previously utilized solely for blue-yellow color vision, essentially bifurcating into red-green cones and blue-yellow cones so that the monkeys examined developed full color vision like human beings as of 2019. The Neitz’s confirmed this by providing male squirrel monkeys colorblind examinations which when answered correctly, delivered a small treat of food after having undergone gene therapy. Trials in human beings have yet to start as the Neitz’s believe that this step is still a few years away, but expected to initiate during the 2020’s

The Danger of Air Pollution Gaining Access to the Brain

Leave a comment

The reason pollution has a metallic taste and scent and that it burns the eyes when exposed to it is because the particles of air pollution are tiny enough that they can travel through nerve cells, and gain direct entry to the brain, where the olfactory bulbar meets the frontal cortex, as there is no blood-brain barrier at this point. The body protects itself through the blood-brain barrier, which means that particles within the bloodstream, cannot get directly into the brain. This system has a slight flaw however as the nose acts as a direct conduit for incredibly tiny particles to bypass this security mechanism

The Reason Islamic Carpet Design is Geometric

Leave a comment

Carpet weaving is thought to have originated in Central Asia more than 2000 years ago, but it was the Islamic culture which shifted it into an art form. Many Islamic traditions have long frowned upon the depiction of sentient beings depicted in western art and because of this, carpet makers created landscapes of bright colors and complex patterns, with the mark of different tribes and ethnic groups recognized by the various dyes and pattern styles utilized. Patterns are so prevalent in Islamic culture because it is a form of expression which is permitted, unlike many others which go against the direct teachings of the Quran. It’s common for patterns to contain an eye somewhere along the line as a protective measure, or a small script to give thanks and praise to Allah, and sometimes even small depictions of hidden meanings like the head of a bird without the rest of its body. Typically, duplicates of the same Islamic carpet are not created, as the artist who created the original design did so because they felt a particular emotion during the creative process and because the same mood is or was not felt during the next carpet, the design is different to reflect the new mood experienced. The golden age of the Islamic carpet occurred during the 17th century when landscape art worked its way into these carpets causing them to become portable gardens of paradise. The images portrayed were not intended to hold a mirror up to nature, but to reflect what human beings value most of nature

The Evolution of the Eye

Leave a comment

The eye has developed within the animal kingdom for one reason only; to detect the world around the observer. The first evolved eyes were simply an apparatus which had a light sensitive cell referred to as “rhodopsin”. Eventually as time progressed, eyes developed a spherical shape which allowed more light to be captured so that the difference between light and dark was more distinct. Following this, eyes evolved the ability to develop a pupil which acts as a biological aperture which can constrict and dilate letting either more or less light into the eye. This system works in theory but the real world application developed a problem in that when constricting the pupil to focus on an object being looked at, less light is let in which restricts vision. Nature eventually alleviated this issue by placing a lens behind the aperture of the pupil which allowed for precision detail, clarity, and focus. This system was so effective that evolution produced some form of it for nearly every animal and insect on Earth, some being more adept than others, but all using the same principal of light and focus to observe information around them

Herbivore vs Carnivore Vision

3 Comments

Animals which have eyes placed upon the sides of their heads (e.g. squirrels, zebras, frogs etc.) are typically herbivores and prey for carnivores. Herbivores need to have their field of vision constantly focused upon what’s going on around them. Animals which have eyes on the front of their heads (e.g. owls, tigers, human beings etc.) are usually carnivores. Carnivores are predators and because of this they need to constantly be focused upon what is in front of them for activities like chasing down prey in an attempt to capture and eventually kill what they catch. Human beings can demonstrate this difference for themselves by placing one’s hands in front of their eyes as they would binoculars, then crossing their wrists and cupping their hands so that they see only from the sides of their face. This demonstrates the different abilities predator and prey have in respect to what is in focus within a particular classifications field of vision. Panoramic vantage points which herbivore prey have allow for more information to be taken in at once, but binocular vantage points which carnivorous predators have allow for depth perception which most herbivores do not have, and even when they do have it, it’s accuracy is highly limited