Assignment 228 .
What is the refractive error?
Normally, the rays of light entering the eye are brought to a precise focus on the retina, the light sensitive layer lining the back of the eye. When such a focus is not achieved, a refractive error results and vision is not clear. These defects in the focusing power of the eye are called refractive errors, most common symptoms of refractive error is blurry vision.
Ophthalmologist can serve the patient by asking questions and obtain information, and by use many of devices (retinoscopy, autorefractor) to detect the error.
Emmetropia (normal eye):
Normally refractive condition of the eye, in which with accommodation relaxed, parallel rays of light are all brought accurately to focus on the retina. …show more content…
Causes of these error:
Hyperopia is occurred when the eye is shorter than normal or has cornea too flat, or the lense is sits farther back in the eye than it’s should. Hyperopia is make condition with presbyopia, that is maybe occur a near vision in some cases for the persons over than 40yrs . In Myopia occur when the eyeball becomes too long than normal that is prevent incoming rays to focused on the retina, it is also me caused by the cornea and lens it is being, too curved (abnormal) In Astigmatism, there is not exact cause of it, all the people or many of them born with, or maybe occur after the eye surgery or eye diseases, and most said it’s occur if the person read in low light, or sit too close from the TV, but that is doesn't true In presbyopia occur related to the age, natural lens inside the eye gradually losing it's flexibility and result in blurry vision for reading and near work .
Pathophysiology:
In general, all these errors happen if become change in lens, cornea, muscles, and capsule by increase curve or decrease it, become too long or too short, and maybe occur by decrease or increase …show more content…
Only convergent incident light rays can be focused on the retina. This is due either to an excessively short globe with normal refractive power (axial hyperopia; or, less frequently, to insufficient refractive power in a normal-length globe. Axial hyperopia is usually congenital and is characterized by a shallow anterior chamber with a thick sclera and well developed ciliary muscle. In nearsighted patient, which occurs when increasing the refraction of light rays entering the eye to be assembled at one point before they reach the retina. When you have shortsighted, your eyes may be longer than normal or may be increased the curved cornea. As a result, the pictures you see are not assembled as it should on the
What is the refractive error?
Normally, the rays of light entering the eye are brought to a precise focus on the retina, the light sensitive layer lining the back of the eye. When such a focus is not achieved, a refractive error results and vision is not clear. These defects in the focusing power of the eye are called refractive errors, most common symptoms of refractive error is blurry vision.
Ophthalmologist can serve the patient by asking questions and obtain information, and by use many of devices (retinoscopy, autorefractor) to detect the error.
Emmetropia (normal eye):
Normally refractive condition of the eye, in which with accommodation relaxed, parallel rays of light are all brought accurately to focus on the retina. …show more content…
Causes of these error:
Hyperopia is occurred when the eye is shorter than normal or has cornea too flat, or the lense is sits farther back in the eye than it’s should. Hyperopia is make condition with presbyopia, that is maybe occur a near vision in some cases for the persons over than 40yrs . In Myopia occur when the eyeball becomes too long than normal that is prevent incoming rays to focused on the retina, it is also me caused by the cornea and lens it is being, too curved (abnormal) In Astigmatism, there is not exact cause of it, all the people or many of them born with, or maybe occur after the eye surgery or eye diseases, and most said it’s occur if the person read in low light, or sit too close from the TV, but that is doesn't true In presbyopia occur related to the age, natural lens inside the eye gradually losing it's flexibility and result in blurry vision for reading and near work .
Pathophysiology:
In general, all these errors happen if become change in lens, cornea, muscles, and capsule by increase curve or decrease it, become too long or too short, and maybe occur by decrease or increase …show more content…
Only convergent incident light rays can be focused on the retina. This is due either to an excessively short globe with normal refractive power (axial hyperopia; or, less frequently, to insufficient refractive power in a normal-length globe. Axial hyperopia is usually congenital and is characterized by a shallow anterior chamber with a thick sclera and well developed ciliary muscle. In nearsighted patient, which occurs when increasing the refraction of light rays entering the eye to be assembled at one point before they reach the retina. When you have shortsighted, your eyes may be longer than normal or may be increased the curved cornea. As a result, the pictures you see are not assembled as it should on the