“The word cataract comes from the Greek word cataractos, which means rapidly running water. When water is turbulent, it is transformed from a clear medium to white and cloudy.” Although the Greeks named cataracts they weren’t sure what caused the clouding they observed but thanks to modern science we are one step closer to understanding. Cataracts are a condition where the lens of the eye, which in healthy people is clear, becomes cloudy due to changes in the proteins that make up the lens of the eye. . The lens of the eye is partly responsible for focusing light onto the retina, the part of the eyes that detects light. However when the lens of the eye becomes cloudy the light is refracted and because the light cannot be focused on the retina, …show more content…
vision becomes blurry. This blurry vision has been described “like looking through a frosty or fogged-up window.” While cataracts do not pose any threat to people lives, cataracts can reduce the quality of living by impeding people’s vision and preventing them from completing their day to day activities.
Cataracts are actually the number one cause of “vision loss in people over age 40 and is the principal cause of blindness in the world.” “By age 65, over 90 percent of people have a cataract and half of the people between the ages of 75 and 85 have lost some vision due to a cataract.” One of the reasons for this is because there is very little known about what causes cataracts and much less how to prevent them. Cataracts also develop slowly and many times people who have cataracts don’t even know it because they don’t disturb their daily vision but over time cataracts can cause …show more content…
problems. An important step to understanding how cataracts cause cloudy vision is by knowing how the eye works. The eye is composed of many parts which all contribute to the sense of vision however for our purposes we will only talk about the parts that contribute directly with focusing and interpreting light. The main parts responsible for focusing and interpreting light are the cornea, the iris and pupil, the lens and the retina. The cornea is clear, dome-shaped and covers the surface of the eye.
It’s mainly made of proteins, collagen and water. The main functions of the cornea are to protect the eye from germs, dust, and other harmful matter and to focus light on to the lens.
The iris is the pigmented part of the eye that is responsible for giving eyes their color. Its main function is to control the amount of light that reaches the retina. This is done by changing the size or the pupils by contracting the sphincter pupillae which contracts the pupil or contracting the dilator pupillae which pull the iris enlarge the pupil.
The lens is a
When light strikes the cornea, it bends–or refracts–the incoming light onto the lens. The cornea contributes between 65-75 percent of the eye’s total focusing power. The lens further refocuses that light onto the retina, a layer of light sensing cells lining the back of the eye that starts the translation of light into vision. For you to see clearly, light rays must be focused by the cornea and lens to fall precisely on the retina. The retina converts the light rays into impulses that are sent through the optic nerve to the brain, which interprets them as
images. The way we see the world is dependent on how light is focused in our eye. The process of sight starts with light passing through the cornea of the eye. The cornea is the clear lens on the front part of the eye that is primarily responsible for focusing light. Then the light passes through the pupil which is an opening in the iris or the colored part of the eye. The iris functions like the shutter on a camera by controlling how much light enters the eye by either contracting and making the pupil smaller or by relaxing and making the pupil larger. The portion of the light that made it throught the pupil then meets the lens of the eye. The lens of the eye then helps focus the light even more precisely on to the retina. The retina is the portion of the back of the eye that hasspecialized cells that detect light and convert the light into an electrical signal. The signal is then sent to the visual cortex or the part of the brain that interprets the signal as an image. What causes cataracts? How do you fix them?
Optometrists have accepted vision therapy, which is a medical treatment for optical muscle disabilities, as a feasible treatment used for eye related problems; claiming the treatment can strengthen vision and give the patient the opportunity to understand visuals quicker and clearer (Press). Vision therapy originated in the 1950s and over the past 25 years, has gained popularity, mainly because of new technological innovations in the field of treatment. Generally, vision therapy is prescribed as a measure mainly for people between the ages of 3 and 18. With the results from a comprehensive series of eye tests, the optometrist can work with the patient using special instruments—prisms, filters, occluders, and eye lenses—and strengthen the eye muscles, thus improving sight. According to optometrists in favor of vision therapy, these methods of treatment using these instruments function as safer routes to repair eye disabilities. Although vision therapy can yield favorable results, the practice as a treatment for innate eye disabilities has been in hot debate lately; as it can exceed $8000 and insurance companies do not cover the treatment. For decades, insurance companies have refused to accept vision therapy as a legitimate method for repairing eyesight (Boink). Concomitant with lack of insurance, the cost for a full treatment can exceed $8000, and doctors cannot guarantee a successful outcome. Recently, parents of children with eye related disabilities, such as amblyopia (lazy eye) and strabismus (cross-eye), and doctors have attempted to cooperate with public schools to allow families access to school-funded doctors to practice vision therapy. With a tight budget, most schools cannot afford to supply vision therapy, and a...
Myopia is defined as nearsightedness, which exists when the refractive elements of the eye (cornea and lens) place the image in front of the retina. The myopic condition is common in infants but generally levels off to normal vision as the infant ages (Vander & Gault, 1998). Myopia occurs in about 25% of the adult U.S. population. Many adults use corrective lenses or contacts to correct their myopic vision to 20/20 vision (Drexler et al., 1998). Many people find contacts or glasses hindering in their personal and/or professional lifestyle. For example, military pilots cannot wear glasses while flying and some firemen may find glasses too dangerous to wear during a rescue attempt. There is refractive surgery available to correct myopic eyes, like Photorefractive Keratectomy (PRK). Why do people have myopia, what can be done to correct myopia, and what are the results of corrective surgical procedures? These are a few questions that will be addressed and analyzed.
Vision loss from glaucoma is permanent but can be prevented with early detection and treatment. Since the symptoms of the disease are usually unnoticeable, regular eye examination are important especially for persons over the age of 35 and those in high risk group.
The pupil is where light can enter the eye. The iris is in control of the amount of light that actually goes through. The light reaches the lens, which alters the shape of it so the eye can focus on it. Light reaches the retina, which consists of cones and rods. Colors are saw differently based on their implied meanings, which to various psychological functions. The cones are responsible for color. The color red would have such an effect on people’s perception of others based on their production of affect, behavior and cognition. A sociocultural theorist would explain this effect by indicating that the associations with the color red are normal. When a student sees a plethora of red marks on their paper, they automatically think they failed the assignment. Biological theorist would best explain this theory by saying the color red helps them survive or reproduce. A man may be attracted to a woman more because she is wearing red. This attractiveness could cause him to find his mate and eventually reproduce. A behavioral theorist would explain this effect by saying the color red provokes pleasure and avoids pain. A person can associate red with romance and
With no treatment needed, glaucoma is a leading cause of blindness in the United States, while simultaneously being the number one leading cause in Africa (Glaucoma Research Foundation). According to the American Optometric Association, “Glaucoma is a group of eye diseases causing optic nerve damage. The optic nerve carries images from the retina, which is the specialized light sensing tissue, to the brain so we can see.” They go on to say that when dealing with glaucoma, one’s eye pressure plays a vital role in damaging the delicate nerve fibers of the optic nerve. “When a significant number of nerve fibers are damaged, blind spots develop in the field of vision. Once nerve damage and visual loss occur, it is permanent.” The National Institute of Health states that due to shallower anterior chamber depths, this defect hurts the lives of people mostly from East Asian descent. The Foundation continues to say that blacks are among the people who are three times more likely to have glaucoma while woman in general are two times more likely to developing angle closure glaucoma.
According to Baily and Hall, while visual impairment early in life is associated with inherited congenital disorders, abnormal fetal devepment, and problems associated with premature birth, most eye conditions are associated with aging. They claim that over 70% of the visually impaired population in the United States is over 65. Age related maculopathy, also called macular degeneration, or AMD, impairs the center of vision in older individuals. The macula is the region in the back of the retina that surrounds and includes the fovea (Goldstein 1999). It is important to understand that when this degeneration progresses enough, the condition constitutes blindness because the foveal area is what is used to focus on something. Most cases do not progress this far, but between five and 20% do. Allikments and Shroyer claim that 11 million people in the United States alone suffer some degree of this impairment, with 75% of those individuals being 75 or older. Seven percent of this older age group reportedly suffer advanced forms. Freidman reports the disease as most common in developed countries.
An inspection of the modern animal phyla will reveal that eyes are just as diverse as they are complex. Some organisms like the rag worm have pigmented cup eyes while other like he box jellyfish have two lens eyes and two pairs of pigment pit eyes. To account for the diversity in eye structure, we must first examine the eye ‘prototype’, the original structure that was acted upon by evolution. The simplest organ that can be considered an eye is composed of a single photoreceptor cell and a single pigment cell, without any lens or other refractive body (Arendt, 2003). Such organs are know as eyespots, and...
Life revolves around being able to see things. Although individuals who are blind can lead a full and happy life, someone with excellent vision who suddenly loses theirs or notices a decrease in their visual acuity over time may find it difficult to adapt. Thankfully, with the help of an optometrist, individuals can actively work to preserve their vision for as long as possible. Phoenix Eye Care must be a priority for all, as advanced technology allows threats to the eyes to be detected at the earliest stage. The right treatment can help to slow or stop the progression before major issues develop.
Macular degeneration also known as late, aged-related maculopathy is an eye disorder which causes a decrease in the visual field known as the retinal macula (Medical Encyclopedia, 2000). The majority of people who are affected are people over the age of 65, but occasionally it develops earlier in people 40-50 years old (Philippi, 2000). The majority of the visual loss is located in the central part of the visual field, while the peripheral vision is unharmed. There are also two types of macular degeneration, the "wet" and "dry" forms. The "dry" form of this disease is the most popular, affecting 90% of the cases (American Academy of Ophthalmology, 1997).
The iris acts to control the size of the pupil. In bright light, the iris is dilated in such a way as to reduce the size of the pupil and limit the amount of entering light. In dim light, the iris adjusts its size as to maximize the size of the pupil and increase the amount of incoming light.
Fluid circulating inside the front portion of the eye is produced by a structure called the ciliary body, which is located behind the iris. This fluid moves through the opening of the pupil, passes into the space between the iris and the cornea, and drains out of the eye through a tissue called the angle. With glaucoma, the passing of fluid through the angle is either reduced or suddenly stops, and amounts of fluid inside the eye increase. This high fluid pressure hurts the nerve fibers and the eye's optic nerve and causes blind spots. It may lead to blindness in some cases.
and the iris which is the colored part of the eye, it regulates the amount of light
To understand the technology that helps correct eye sight, one must know about the parts of the eye, what the functions of the eye parts are, and the structure/ anatomy of the eye. There are vast parts of the eye, so only the most important and known will be listed. The list is ciliary body, sclera, choroid, retina, fovea, macula, optic nerve, optic disk, vitreous humor, lens, aqueous humor, pupil, iris, and cornea. All these parts of the eye are the reason why people can see and without one of these parts their vision will be extremely damaged, if not blind. The ciliary body is the transparent part of the eye which is connected to the lens that releases aqueous humor (a liquid) and it also controls a muscle which changes the shape while the eye is focusing. The sclera is the tough white out layer that is connected to the optic nerves to help the structure and safety of the eye. The choroid is located in between the sclera and the retina, and it provides blood supplies, which also nourishes the eye. The
This reflected light passes through the lens and falls on to the retina of the eye. Here, the light induces nerve impulses that travel through the optic nerve to the brain, where it makes an image of the object, and then that image is passed on to muscles and glands.The eye is well protected. It lies within a bony socket of the skull. The eyelids guard it in front. They blink an average of once every six seconds. This washes the eye with the salty secretion from the tear, or lachrymal, glands.