Common Visual Problems
When you are myopic (short-sighted), close-up objects seem clear but images in the distance will seem blurry. Here, your eye is too long and/or the cornea is too curved. Images are focused in-front of the retina, so your brain interprets it as a blurred image.
Hypermaetropia (youthful long-sightedness)
When you are hypermaetropic (long-sighted), objects in the distance are slightly blurred while objects that are near seem more blurred. Here, your eye is too short and/or the cornea is too flat. Images are focused behind the retina, so your brain interprets it as a blurred image.
When you have astigmatism all objects seem blurry, whether near or far. Here, the shape of the cornea is distorted. Images are focused on more than one point in-front of, or behind the retina, so your brain interprets it as a "doubled" image.
LASIK can correct myopia, hypermaetropia and astigmatism by changing the curvature of the cornea.
Presbyopia (old age long sightedness or "Lau Hwa Yan")
When you have presbyopia, usually in middle age (between 40-45 yrs old), distant objects appear clear but you need reading glasses to see near objects clearly. As you age, your eye's lens loses elasticity and cannot fine-tune the focus of light on the retina properly.
LASIK cannot correct presbyopia because the procedure cannot change the elasticity of the lens.
Every year, claims of a cure for presbyopia are made all over the world. Unfortunately, none has been able to completely cure presbyopia. Laser Thermokeratoplasty, Conductive Keratoplasty, scleral expansion plugs, accommodative intraocular lens, multifocal intraocular lenses and presbyopic LASIK surgery all have had limited success.
Even so, presbyopic LASIK surgery has recently received intense publicity. This surgery is designed to change the shape of the cornea to a multifocal and more prolate (conical) shape. This increases the depth of focus, but cannot eliminate the basic problem of stiffening in an ageing human lens.
The final cure will be an artificial lens with the ability to change its shape by entirely mimicking the way the human lens focuses. Billions of dollars have been invested to design and test various lenses but presently, none are able to focus as effectively as the natural human lens.
Confusion Over The Term "Long-Sightedness"
"Long-sightedness" is used to describe two different and distinct conditions - Hypermaetropia and Presbyopia - both of which cause blurred vision at close range. The term "long sightedness" has led to much confusion amongst patients, and even doctors.
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Before you proceed with LASIK, it is important to determine whether you are hypermaetropic or presbyopic.