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Home Introduction Purpose and Hypothesis Materials and Procedures Observation and Analysis Discussion Conclusion The Fact about Eye Problems References Acknowledgements
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Many students are having eye problems. The most common eye problems for them are short sightedness, long sightedness and astigmatism. Myopia
Myopia is also known as short sightedness; (viii) the eye is not able to focus on a distant object, making it seems blurred, but near objects can been seen clearly because eyeball may be slightly longer than normal or the light focused in front of the retina. It is not totally inherited; it is also caused by using computer, watching television, etc. The
diagrams for normal vision, Myopia and corrected Myopia TreatmentMyopia can be corrected by glasses and contact lenses, (viii) which compensate for the elongated shape of the eye that allowing light to focus on the retina. Glasses are less expensive than contact lenses and the safest way to correct refractive errors, improve eyesight by putting a lens a front of the eyes, but some people may think it is uncomfortable to wear, since the glasses may get in the way of some works and fog up in humid. However, contact lenses are better, since it provide a wide range for individual needs, it gives a better side vision. But people must clean and disinfect the lenses, if not it may cause scratches of the cornea and dry eyes, etc. The other method is getting a laser surgery. But LASIK, PRK and RK do not cure Myopia, only vision correction surgery (refractive surgery) does. (vii) In the surgery, the ophthalmologist will use the excimer laser to flatten the curve of the cornea, removes corneal tissue from the central zone and apical zone, and create a new living “lens”. After the treatment, the image is focused in front of the retina since the cornea bends light too much.
Hyperopia
Hyperopia is known as farsightedness or long sightedness; it is a refractive error. The eye is not able to focus on a near object; it results in blurry in near objects, headaches when doing some near works and even fatigue when reading. This vision problem occurs because the light focuses behind the retina when it is entering the eye. This is caused by a cornea, which is flatter or the eye, which is shorter than the normal eye. It is usually inherited. The diagram for normal eye
and Hyperopia Treatment
Hyperopia is same as Myopia, it can be corrected by glasses, contact lenses and laser surgery. (vii) In the laser surgery, a laser surgeon makes the eye’s center steeper by removing the tissue in a circular pattern around the mid-periphery of the cornea. The excimer laser removes corneal tissue from the midapical zone at about 7mm. After the surgery, the cornea will curve more so that the light can focus on the retina. There is also another operation called hyperopic LASIK or H-LASIK. But H-LASIK is less accurate than refractive surgery for Myopia, it may take 2 or 3 months to carry out the operation. The goal of it is same as refractive surgery; make the cornea more curves. So the light will focus on the retina instead of behind the retina.
Carotenoid
Carotenoids are organic, (xvii) fat-soluble pigments that are naturally occurring in plants, algae and photosynthetic bacteria that provide bright coloration. They are responsible for many of the red, orange and yellow hues of plants, leaves, fruits and flowers. They are derived from a 40-carbon polyene chain that can be terminated by cyclic end-group. On the other hand, it also can be complemented by oxygen-containing functional groups. In addition, they show distinctive pattern from others that they alternate single and double bonds in polyene backbone of carotenoid that allows them to absorb excess energy from molecules. Further more, they act as biological antioxidants that protect cells and tissues from damaging effects of free radicals and singlet oxygen. Since Carotenoid is a type of Vitamin A, so it helps prevent night-blindness and improve eye vision
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