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The eyeball is a spherical organ situated in a bony cavity called the orbit. The muscles are located not only on each side of the eye, but also on the top and the bottom of the eye.
Based on this primary description of the anatomy of the eye, it can be deduced that the eye is such a highly sensitive organ that proper attention and safeguard must be taken into consideration. Since many problems and health habits begin in childhood, sound principles of safe care need to be stressed at this time.
Complaints such these need to be investigated: headaches, dizziness, tiredness after close eye work, ˆcannot see well,˜ letters jump or run together, or eyes that feel scratchy or itchy. The appearance of inflamed or watery eyes, red rimmed, encrusted or puffy lids, recurring sties, crossed eyes, and unequal pupils may be significant. Unusual behavior also should be noted such as holding a book too close, frowning, blinking, etc. A combination of these signs may be a short duration and often expected with an upper respiratory infection. However, persistence of these complaints indicates the need for a vision correction.
Vision and Vision Correction
Just as the eyes often reflect a systemic problem, an eye weakness may affect the total well-being of a person. The concept of total health care must be recognized by the health experts. An individual may complain of a minor visual disturbance and pass it off as something that may clear by itself. Such procrastination may have serious consequences. On the other hand, any visual disturbance must be dealt with properly and should be given full treatment on an instant. With the help of some technological advancement that focus on vision correction, people can now enjoy their benefits aside from the usual help that the contact lenses and eyeglasses bring.
Vision correction is applied to people whose normal vision had elapsed. Normally, humans have a ˆ20/20 vision,˜ which means they can see anything to as far as 20 feet to that of what a regular vision is ˆseeing˜ at 20 feet. However, the concept of vision is not primarily focused on the object, rather humans see the ˆlight˜ that is being reflected from the objects.
Vision correction is applied if there is an abnormality in the usual method of transporting the light rays from the object to the cornea, the vitreous humor to the retina, the lens, and the aqueous humor.
Hence, any kind of refractive errors need vision correction. For instance, nearsightedness or myopia takes place when the light is primarily focused on the face of the retina. In certain state, vision correction is applied through the help of eyeglasses.
Rays from objects situated at shorter distances or less than 6 meters require a ˆstronger˜ lens to focus them on the retina. This is brought about by a contraction of the ciliary muscle that relaxes the lens capsule and causes the lens to become more convex. This function is called accommodation, where the objects at different distances from the eye may be seen distinctly. To understand more, here are some of the common refractive errors that require vision correction:
1. Presbyopia
With increasing age, the elasticity of the lens decreases, and accommodation for near vision is not complete. For example, it is common to see older people reading a paper held at arm´s length; this condition is known as presbyopia. It primarily pertains to the lessening of power of accommodation owing to aging process. ˆReading eyeglasses˜ is the common form of vision correction prescribed for these patients to enable them to focus rays from near objects on the retina.
2. Astigmatism
This type of refractive error results from uneven curvature of the cornea ˙ instead of curving equally in all directions. The cornea is shaped somewhat like the bowl of a spoon.
Two foci, thus, occur instead of one and, as a consequence, the patient is unable to focus horizontal and vertical rays on the retina at the same time. These defects may be corrected with lenses called ˆcylinder lenses.˜ Considering these few examples of refractive errors, external and internal examination of the eye must be applied first before the eye doctor can prescribe the right form of vision correction.
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