Refractive Errors of Eye
Refractive Errors of Eye
Refractive Errors of Eye
ERRORS OF EYE
By Ishita Aggarwal
1621077
INTRODUCTION
A refractive error is a very common eye disorder. It occurs
when the eye cannot clearly focus the image from the
outside world.
The result of refractive error is blurred vision which is
sometimes so severe that it causes visual impairment.
Refractive error also known as refraction error is a
problem with focusing light accurately on the retina
due to the shape of eye.
TYPES OF REFRACTIVE
ERROR
The types of refractive errors are:
Myopia
Hyperopia
Astigmatism
Presbyopia
MYOPIA
It is near sightedness also known as short
sightedness.
It is a type of refractive error in which parallel rays of
light coming from infinity are focused in front of the
retina when accommodation is at rest.
Myopia is a condition of the eye where light focuses
in front of the retina instead of on the retina this
causes distant objects to be blurred while close
objects appear normal.
ETIOLOGY OF MYOPIA
● Axial myopia results from increase in the antero
posterior length of the eyeball.
● Curvatural myopia occurs due to increased
curvature of the cornea, lens or both.
● Index myopia results from increase in the
refractive index of the crystalline lens associated
with nuclear sclerosis.
PATHOPHYSIOLOGY
MANAGEMENT
• Concave lenses in the form of glasses or
contact lenses.
• Radial keratotomy: Multiple radial incisions
are given in the periphery of cornea in order
to flatten the curvature of cornea.
• Lasik laser: Laser assisted in situ the
preferred surgical technique for correcting
myopia of up to -12 D.
• Orthokeratology: A non surgical reversible
method of molding the cornea with
overnight wear unique rigid gas permeable
contact lenses.
HYPERMETROPIA
Hypermetropia (hyperopia) or long sightedness is the
refractive state of the eye where in parallel rays of light
coming from infinity are focused behind the retina with
accommodation being at rest. Thus the posterior focal
point is behind the retina, which therefore receives a
blurred image.
ETIOLOGY
● Axial hypermetropia is by far the commonest form. It occurs due to
short axial length of the eyeball.
● Curvatural hypermetropia occurs due to comparatively flatter
curvature of the cornea or lens or both.
● Index hypermetropia results due to change in the refractive index of
the lens.
● Absence of the lens (aphakia) either congenital or acquired (following
surgical removal of the lens) leads to high hypermetropia.
CREDITS: This presentation template was created by
CLINICAL FEATURES Tiredness of eyes Frontal or frontotemporal
Slidesgo, including icons by Flaticon and
infographics & images by Freepik
headache Watering Mild photophobia
MANAGEMENT
Appropriate convex lenses in
the form of spectacles or
contact lenses.
Refractive corneal surgery
ASTIGMATISM
Astigmatism is a type of refractive error where in the
refraction varies in the different meridian of the eye
consequently, the ray of light entering in the eye cannot
converge to a point focus but form focal lines.
ETIOLOGY
Usually occurs due to
TYPES OF
unequal curvature of cornea.
ASTIGMATISM-
Rarely it may occur due to Regular Astigmatism
subluxation abnormalities of Irregular Astigmatism
the curvature of the lens.