Come See What Eye See
By: Vanessa Cano
Glasses have been a tool I have relied on for at least the last 5 years. Without them, my eyesight would leave me with many disadvantages in life and a very blurry view of the world. But why is it that the eyes that we rely on so much to view the world sometimes fail our needs? Because of how it has affected my life, I have slowly learned about the abundance of physics behind the eye that helps explain our ability to see in our lives.
There are a few theories on vision including Plato who believe the light emanated from the eye, seizing objects with its rays while Ariste was among the first to reject the extramission theory of vision. Galen believed in the image of sight as a function of an optical pneuma, flowing forth from the brain to the eyes though hollow optic nerves. By the 16th century, the theory of vision did not change greatly, but the anatomy of the eye still held different views. There were arguments on the priancy of the crystalline lens, whether the optic nerves were hollow or not, and if the crystalline humor was actually round and centered but more oblong and towards the front of the eye. It wasn’t until Felix Platter where the retina as we know today as the primary role of vision was finally held as the “primary organ of vision” while the crystalline humor was a secondary role. However, this is only the beginning of the research of ophthalmology
.The history of the development of optometry truly began in the 18th and 19th century where opticians studied visual optics and began forming a large body. However, what is overlooked, is the craftsmanship behind optometry and the way it is analogous to that of engineering in the viewpoints of craftsmen origin. Strongly influenced by physics, optometry belonged to the physics department rather than to the medical school in American universities. It wasn’t until the 1930s where optometry became independent of physics and researchers focused on binocular visions that are not a part of the disciplines of physics. Hence, the history of optometry may not align with the history of ophthalmology as seen from prior history. It is also to point that the physical optics include interference, fluorescence, and ansorptiomentry that has led to many non-invasive diagnostic examination techniques in optometry.
To understand the physics, one has to understand the properties of lights. Light passes through the cornea and into the lens, a transparent, flexible tissue. The iris regulates the amount of light by controlling the size of the pupil and emits the light to the back interior wall of the eye. The wall contains tissue known as the retina that contains millions of light-sensitive cells. It covers about 65 percent of the eye’s interior service and contains a small dimple, fovea, where the sharpest vision is held and the most color perception. Our vision is formed on the retina when the lights converge and the top and bottom that produce an inverted real image. Hence nearsightedness happens if the eyeball is too long or the cornea has too much curvature. The light isn’t focused when it enters the light and their distant view is blurred.
Optometrists work in creating ways to help people be able to see in their everyday life. This includes vision being corrected by eyeglasses or contact lenses that alter the way the light enters eyes. In farsightedness, the lens of the eyeglasses bend the light towards toe top and bottom pushing the focal point back to the retina in which the stronger the lens, the closer the focal point is. In nearsightedness, the lens spreads the light away from the center and moves the focal point up. In general, glasses rely on the mechanics of the eye to work and the lens are two rounded prismes joined together that are always thicker at one end and light passes through either bent or refracted towards the thicker end. Depending on the lens shape, spherical, cylindrical, and compound lenses have their own functions when it comes to eyeglasses.
Our eyesight is sometimes taken for granted, but in reality, 80% of what we perceive comes through our sense of sight. It is our most developed sense that is used as tools, and living our everyday lives. Because of its complexity and precision, it is important to continue to study ophthalmology for a hopefully, better and easier quality of life.
The Gift of Sight: Can CRISPR Cure Blindness?
By: Avantika Samanta
Eyes–one of the many miracles of human life. They are made up of over 2 million working parts, and each individual eye has 107 million light sensitive cells. Yet, eyes can be defective, globally speaking 39 million people are blind. There are certain rare genetic conditions that can cause blindness, and new technologies are paving the way for possible treatments for blindness, which can be caused by these genetic defects. These cures involve CRISPR, an important technology that is becoming increasingly popular. CRISPR is revolutionizing the scientific community, and in this case, it might just be able to cure some cases of blindness.
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats, and refers to specific DNA sequences that can be found in bacteria and other organisms. It’s an important part of the immune system, it works by destroying a virus’s genome, therefore preventing it from replicating and spreading. It acts like a pair of DNA cutting scissors where Cas9, a protein created by the CRISPR system, attaches itself to the viral DNA and cuts it, shutting the gene off.
Researchers are attempting to use CRISPR to try and cure genetic mutations that cause blindness, yet there are many genetic mutations that can cause blindness. Scientists at the Columbia University Medical Center and the University of Iowa have used CRISPR to repair an inherited genetic defect called retinitis pigmentosa (RP). From a piece of skin acquired from a patient with retinitis pigmentosa, researchers created stem cells. These stem cells can possibly be transformed into healthy retinal cells and be transplanted back into the patient. This method shows promise because not only is CRISPR precise and accurate, but scientists are taking the patient’s own cells so there is less fear of rejection, making it more safe and effective.
Another potential area where CRISPR can be used to treat blindness would be in patients who suffer from a childhood disease called Leber congenital amaurosis (LCA). The condition begins during a patient’s infancy, patients are unable to create protein CEP290 which causes the destruction of light-sensing cells in the retina, photoreceptors, that are needed for vision. This treatment was the first time CRISPR editing was ever used directly within a patient, the first time ever. The patients would receive a dose of the gene therapy while under anesthesia, then the retina surgeon uses a scope, needle and syringe to inject the CRISPR enzyme to the back of the eye near the photoreceptors. The goal is that once the CRISPR instructions are infused into the eye the system will edit the genes, cutting out the defect that causes blindness and restoring the protein needed, thus preventing the death of cells in the retina.
At this point in time, the leber congenital amaurosis (LCA) treatment mentioned is the only in vivo (meaning within a person), CRISPR procedure that is approved by the FDA. The retinitis pigmentosa shows great amounts of promise but it still isn’t approved for use on humans. This is a new technology, the possibilities are endless. But with endless possibilities come countless responsibilities. These treatments have to be rigorously monitored and tested before they become easily accessible to the public. And these solutions are deemed to be “Forever Fixes” but it’s still unknown if the results are permanent or if these positive results will only last for a period of time. There are possible side effects, effects that researchers may not even know about because these tests are at such an early stage. But optimism doesn’t hurt. If these trials are successful, these methods can be applied to countless other diseases, not just within the realm of ophthalmology. The world is changing, this technology can go on to change the lives of many but as Lao Tzu said, “The journey of a thousand miles must begin with a single step”.
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The Gift of Sight: Can CRISPR Cure Blindness?
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Come See What Eye See
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