Samantha Hutchins 12/8/15 The Optical Lens and Cataracts The optical lenses of the eyes are used to focus light. The light that penetrates the lens is controlled by the iris, which constricts and dilates in response to varying light conditions. Controlling the amount of light that reaches the lens, and subsequently the photoreceptors in the pigmented retina, is not enough to adequately discern images in three dimensions. The lens is therefore responsible for adjusting to conditions based on how far away or near an object is that is being viewed. To view something relatively close, the lens is bent to form a more spherical shape by the ciliary body muscles. Likewise, to view further distanced objects, the lens must undergo accommodation …show more content…
These changes cause a spectrum of decreased acuity in individuals that worsen with time. Early symptoms of cataracts include blurred vision of varying degrees, a fuzzy halo seen around light sources, and a visible yellowing of the lenses causing changes in perceived coloration of objects (Masterson 13). Cataract formation can be exacerbated by certain inherent traits and by environmental effects. Some links to increased cataract formation include older age, being a female, previously existing Myopia, history of smoking, diabetes, and obesity, and also there is an elevated incidence in those with Down syndrome. Often, cataracts are an early detection sign for type II diabetes and diagnosis of diabetes follows the diagnosis of cataract formation. There are also some controversial links that are supported in some literature, such as "Cataracts, Risks, Prevention, Treatment", though refuted in other studies. These links include race, exposure to sunlight, and use of pharmaceutical drugs such as statins (Masterson 13). These contributing factors can cause cataract formation in individuals starting at a young age, though cataracts are most prevalent among the geriatric …show more content…
Fortunately, cataract formation on the optical lenses proves to be a malady that is simple to fix. Future scholarship on such a topic could serve to address the remaining high statistic of blindness due to cataracts. Perhaps formation of cataracts is under diagnosed due to limited health care availability for some individuals. Works Cited Dubbelman, M., G.L Van Der Heijde, H.A. Weeber, and G.F.J.M Vrensen. "Changes in the Internal Structure of the Human Crystalline Lens with Age and Accommodation." Elsevier. Oct. 2003. Web. 08 Dec. 2015. Masterson, Marilyn. "Cataracts, Risks, Prevention, Treatment." Kansas Nurse 90.2 (2015): 13-17 5p. CINAHL Plus with Full Text. Web. 8 Dec. 2015. Salvi, S M, S Akhtar, and Z Currie. “Ageing Changes in the Eye.” Postgraduate Medical Journal 82.971 (2006): 581–587. PMC. Web. 8 Dec.
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...
My interest in the career of optometry stems from my first experience in the optometry office to receive my first pair of glasses when I was in middle school. I distinctly remember the moment when my optometrist slipped my new glasses over my eyes for the first time. Suddenly, everything in the room came into sharp, clear focus. I knew that the glasses would help me see the board in school, but I was astonished to find that I could see small details about the room, as it had never before occurred to me that I should have been able to see these details. I was also surprised that I was even able to see the expressions on the faces of people who were standing far away from me. It was one of the most incredible, freeing, and empowering moments of my life. As I walked out of the optometry office, I felt
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.
Ruckmann, Adrea von, Fitzke, Fredrick W., & Bird, Alan C., (1997). Fundus autofluorescence in age related macular disease imaged with a laser scanning opthalmoscope. Investigative Opthamology and Visual Science, 38 (2), 478-485.
It is a rare condition that affects 2 % of Americans. Signs of pathological myopia include: Bending or distortion of straight lines, altered color perception, reduced contrast sensitivity, and increasing gloss of central vision. It is a quick severe progression of myopia and loss of vision is the end result. There is an increased risk of retinal detachment and other degenerative changes in the back of the eye (bleeding from abnormal blood vessel growth). If any of these things occur the risk of cataracts could increase. Treatment calls for a combination of a drug and a laser procedure called photodynamic therapy. It is reported to be the seventh ranking cause of legal blindness in the United States of America the fourth ranking cause in Hong Kong and the second in parts of China and Japan this form of myopia frequently progresses in adult life, with small intermittent steps of elongation being observable at any age. The adult progression appears to be due to the stretching of the walls of the eye. Genetically weak elements of the scleral wall are prone to thinning and stretching. One of the major forces at work in this stretching process appears to be the normal intra-ocular pressure (Ward
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 as the earliest stage. The right treatment can help to slow or stop the progression before major issues develop. For this reason, every individual needs to undergo routine eye exams.
The human eye’s ability to view focused images of both nearby and distant objects is dependent upon its capacity to accommodate. When you want to look at something nearby, the lens in your eye assumes a large curvature, resulting in a shorter focal length. Conversely, your lens becomes flatter in shape and takes on a longer focal length when you want to look at a distant object. Accommodation is key in allowing your eyes to use its muscles to change focal lengths in order to see objects at a variety of distances. When you lose the ability to accommodate, the lenses in your eyes become locked to focus on either near or far away objects. In the case of nearsighted individuals, light entering the eye can only focus on objects nearby. As a result, distant objects appear blurry because light is focused in front of the retina, or the light-sensitive tissue layer at the back of the eye, instead of directly on it.
The four main components of the eye that are responsible for producing an image are the cornea, lens, ciliary muscles and retina. Incoming light rays first encounter the cornea. The bulging shape of the cornea causes it to refract light similar to a convex lens. Because of the great difference in optical density between the air and the corneal material and because of the shape of the cornea, most of the refraction to incoming light rays takes place here. Light rays then pass through the pupil, and then onto the lens. A small amount of additional refraction takes place here as the light rays are "fine tuned" so that they focus on the retina.
The size of the pupil is firmly linked with the visual acuity. Visual acuity has improved because background lighting rises up to 3400cd/m caused by the blockage of the paraxial ray. Therefore, the peripheral shape of the cornea is require to be controlled in order to deliver more light into the eye.
2.“Idaho eye center”. Modern guides for eye care. ( Pocatello, Id.) 2002 3.Howard Bedrossian, M.D. “The Eye” A Clinical and Basic Science Book. (Blackwell scientific publications. LTD., Oxford, England.) 1958
Understanding how our eyes work can be a really interesting thing. Many people don’t realize vision actually begins when light rays are reflected off an object that then enters the eye through the cornea. The cornea is a transparent bulge, in the front of our eyes that allows us to begin refraction. The cornea is one of the most important things in our eyes that allow us to see the things we do. After the reflected light rays enter the cornea, they then p...
The most common vision issues are the refractive errors, more commonly referred to as nearsightedness, farsightedness, astigmatism and presbyopia. Refractive errors occur when the shape of the eye prevents light from focusing directly on the retina. The length of the eyeball (either longer or shorter), changes in the shape of the cornea, or aging of the lens can cause refractive errors. Most people have one or more of these conditions. In these situations of refraction, the cornea and the lens bend (refract) incoming light rays so they focus precisely on the retina at the back of the eye (figure 2). Refraction is the bending of light as it passes through one object to another. Vision occurs when light rays are bent (refracted) as they pass through the cornea and the lens. The light is then focused on the retina, and then the retina converts the light-rays into messages that are sent through the optic nerve to the brain. The brain after that interpret these messages into the images we see.
Optometry is unique when compared to a field such as general medicine; as a field, optometry is relatively new to many people. The importance of optometry has moved beyond simply helping patients see better, to maintaining the health of the eye and working to screen for many other health conditions. Because its importance is becoming more understood and well known to the general public, the number of patients seeking treatment is growing drastically. As stated above this drastic growth is not only increasing the number of patients but also the number of places optometry is being practiced as well as changing the demographics of the patients being see...