TopicAvoid Choking the Cornea
Astigmatism. People whose eyes focus light rays unevenly have astigmatism. Vision 20/20 Protocol Ebook Review Astigmatism occurs when the cornea has an irregular shape. The cornea should be round and symmetrical like a basketball, but in cases of astigmatism it is shaped more like a football. People with astigmatism see both near and far objects out of focus. Astigmatism frequently accompanies nearsightedness or farsightedness. Before purchasing any new set of spectacles, first go to a good doctor and get your eyes checked. Do not rely on your intuitions saying that you can see perfectly through your present set and that must not necessarily mean that your eye sight is perfectly adjusted with that particular lens. A point five fluctuation of eye power can be seriously degrading to your health. Unknowingly you might succumb your body to severe head aches. You must go to the ophthalmologist whether it is just myopia or hyperopia or something more complex like astigmatism, color blindness or worse still, a cataract.
Presbyopia. Presbyopia (which comes from the Greek for "old vision") refers to the gradual loss, as we age, of the eye's ability to adjust the focus from far to near. Presbyopia is a normal part of the aging process, affecting each and every person, and usually begins to cause a problem with near vision between the ages of forty and fifty. It is corrected by the use of reading glasses or bifocals. Presbyopia occurs because the crystalline lens no longer adequately adjusts its shape to focus clearly on close-up objects.
Though presbyopia is referred to as "farsightedness" by many people, it should not be confused with true farsightedness (hyperopia). Presbyopia is caused by difficulty in changing the focus from far to up close - a problem with the crystalline lens. True farsightedness is caused by too little focusing power in the eye a combination of the cornea and the crystalline lens. The doctor will also be able to accurately be able to tell you what type of lens you need to invest in, after getting to know about your working conditions. If you have to spend a lot of time in front of the computer, he might suggest a photo chromatic lens, or if you are into highly dangerous physical sports, he might recommend impact resistant glasses.