In this blog we will see about correlation between correction of refractive error as uncorrected undercorrected and over corrected of ametropia.
What is a refractive error or ametropia ?
The definition of refractive error is when the parallel rays of light coming from infinity and focus in front of the retina or behind the retina when accommodation at rest is called as a refractive error. Refractive error is also called as ametropia.
When patient see normally without any spectacle or contact lens is called as emmetropia in other word patient visual acuity is 6/6 without any correction is called as emmetropia.
4 type of refractive error ?
What is the correction of refractive error ?
Refractive error correction is given by 2 method subjective refraction and objective refraction. Both method doing bye optometrist, ophthalmic officer and ophthalmologist in Eye care centre.
What is subjective refraction ?
Subjective Refraction is a ophthalmic procedures to determine, the combination of lenses that will provide the best corrected visual acuity (BCVA). Subjective Refraction is a clinical examination used by orthoptists, optometrists and ophthalmologists to determine a patient's need for refractive correction, in the form of glasses or contact lenses.
The aim of this technique is to provide patient to sharp, clear and better vision by contact lens and eye glasses with advanced coating lenses.
Subjective refraction include manual refraction procedure, Jackson cross cylinder (JCC).
What is objective refraction ?
objective refraction is used when the refractive error of an eye is determined without patient response . Retinoscopy is a form of objective in which the judgment of a optometrist, ophthalmologist and ophthalmic officer is required to determine the refractive error.
Objective refraction include retinoscopy, autorefractometry, keratometry.
What is uncorrected refractive error ?
If small degree of refractive error not need to correct It leave uncorrected. Refractive error power below -0.25 it's not need to correct.
What is overcorrected refractive error ?
The prescription power of refraction gives maximum correction power is called as overcorrected of refractive error.
Correction Hypermetropia always give over correct and maximum correction.
What is undercorrected refractive error ?
Minimum power correction for correct the refractive error is called as under correction of refractive error.
The correction of myopia always correct under correction.