4. DEFINITION
Refractive error also is problem with focusing of light on
the retina . The lens is also known as the aquula (Latin, a
little stream, dim. of aqua, water) or crystalline lens.
Refractive error means that the shape of the eye does
not bend light proper and correct resulting in a blurred
image .
18 December 2020 4MOUNESH
5. EMMETROPIA: No optical correction
is needed because the eye is naturally
in optimal focus.
AMETROPIA: Corrective lenses are
necessary to bring the eye to a state of
optimal focus.
18 December 2020 5MOUNESH
6. TYPES OF AMETROPIA
Myopia or nearsightedness
Hyperopia or farsightedness
Astigmatism
Presbyopia
18 December 2020 6MOUNESH
7. MYOPIA
Near-sightedness also known
as short – sightedness and
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.
18 December 2020 7MOUNESH
8. HYPEROPIA
Hyperopia or hypermetropia is caused by an
eyeball that is shorter than normal or from a
cornea that is less curved than normal.
18 December 2020 8MOUNESH
9. ASTIGMATISM
It is a condition in which
an abnormal curvature
of the cornea is not
perfectly spheric.
Cornea cannot bend the
rays of light equally in all
direction, and images are
not properly focused.
18 December 2020 9MOUNESH
10. PRESBYOPIA
Presbyopia is the gradual loss of eyes' ability to focus
on nearby objects (loss of near vision with age)
difficulty in reading or seeing at arm's length.
It's a natural, often annoying part of aging. Presbyopia
usually becomes noticeable in early to mid-40s and
continues to worsen until around age 65.
18 December 2020 MOUNESH 10
15. CLINICAL MANIFESTATIONS
Double vision
Haziness (unclearness)
Glare or halos around bright light
Squinting (it is a condition where the eyes do
not look in the same direction )
18 December 2020 15MOUNESH
17. PATHOPHYSIOLOGY
Due to etiology factors such as infection
Degenerative changes causes by gradual loss of elasticity of
lens
Which leads to decreased ability to accommodate (lens
changing its shape)
Lead to refractive errors
18 December 2020 17MOUNESH
19. DIAGNOSTIC EVALUATIONS
History collection
Physical examination
Corneal topography: It is a computer
assisted diagnostic tool that creates a three-
dimensional map of the surface curvature of
the cornea.
18 December 2020 19MOUNESH
22. MEDICAL MANAGEMENT
Cycloplegic: drugs are used to
refraction ( to paralyze the
ciliary muscle in order to
determine the true refractive
error of eye )
Cholinergics (Miotics): - It
increases aqueous fluid
outflow by contracting the
ciliary muscles. E.g.
Pilocarpine, Carbachol
Analgesic eye drops
18 December 2020 22MOUNESH
30. LASIK-LASER EYE SURGERY
( LASER ASSISTED IN SITU KERETO-
MILEUSIS )
A kind of laser eye surgery designed to
change the shape of the cornea to
eliminate or reduce the need for glasses
and contact lenses in cases of severe
myopia (nearsightedness)
18 December 2020 30MOUNESH
34. AUTOMATIC LAME -LLAR
KERATOPLASTY (ALK)
Keratoplasty is the procedure where by
abnormal corneal tissue is replaced by a
healthy donor cornea.
18 December 2020 34MOUNESH
36. PREVENTIVE MEASURES
Identify the cause & eliminate the cause
Lens correction – a concave lens is used to
correct the problem
Prevention foreign particles enter in eye
Use of sunglasses
Use of antibiotics prevention from infection
18 December 2020 36MOUNESH
