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Three components of the eye work together to detennine the refractive power of the eye: the shape of the cornea, the power of the lens, and the length of the eye. The overall refracting power of the eye is approximately 60 diopters: the cornea contributes about 45 diopters of power, while the lens provides approximately 15 diopters of refractive power to the eye. When the cornea, lens, and length of the eye combine and produce no refractive error, emmetropia is achieved. In the instance of emmetropia, a ray of light parallel to the optical axis and limited by the pupil focuses at a point on the retina. In other words, the secondary focal point is located on the retina. In addition, the “far point” (i.e., the furthest point at which the eye can see clearly) is optical infinity. Because the cornea accounts for approximately 2/3 of the refractive power of the human eye, it is logical that most refractive surgeries attempt to change the shape of the cornea. Other methods of refractive surgery include implanting intraocular lenses which is done by the Titusville laser eye surgeon. Traditionally, four major types of naturally occurring ametropias, or refractive errors, have been described: myopia, hyperopia, astigmatism, and presbyopia. Wavefront analysis of human eyes after correction of these optical abnonnalities often show additional irregularities that have been classified using Zernike polynomials into complex subgroups that may be simplified into lower- and higher-order aberrations. In myopia, the secondary focal point is anterior to the retina. In other words, the refractive power of the eye is greater than that required for emmetropia; parallel rays of light entering the eye are in focus at a location in the vitreous, rather than on the retina. Refractive myopia is due to high lens power or steep corneal curvature or. Axial myopia is due to an eye that is too long (i.e., longer than 22.6 mm). For every mm of axial elongation of the globe, there are 3 diopters of myopia. When myopia is corrected with spectacles, contact lenses, or refractive surgery, the parallel rays of light entering the eye come into focus on the retina, which is consistent with a far point at infinity. The prevalence of physiologic myopia in the general population is approximately 25% (20). titusville laser eye surgeon uses LASIK to correct myopia by removing tissue in the center of the cornea, thereby flattening the cornea and decreasing the refractive power of the eye. One of the best ways to solve vision problem or refractive problem is to consult the laser eye surgeon. Reading the reviews provided by the author is one of the best ways to gain necessary information on Eye doctor Titusville.
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