This document discusses different types of refractive errors including myopia, hyperopia, astigmatism, and presbyopia. It provides details on the causes, clinical features, diagnosis, and correction methods for each type of refractive error. Surgical procedures for correcting refractive errors are also outlined, along with nursing management considerations for pre- and post-operative care.

1. ALIYA
RAHMAN
LECTURER
ERRORS OF REFRACTION

2. introduction
 Refractive error means that the shape of eye
does not bend light correctly, resulting in a blurred
image.
 The main types of refractive errors are
 Myopia (nearsightedness)
 Hyperopia (farsightedness)
 Presbyopia (loss of near vision with age)
 Astigmatism.

4. MYOPIA

5.  Near-sightedness, also known as short-
sightedness and myopia, is a condition of the
eye where light focuses in front of, instead of on,
the retina . This causes distant objects to
be blurry while close objects appear normal
. Severe near-sightedness increases the risk
of retinal detachment cataracts and glaucoma

6.  Most of the cases it is due to physiological
variations in the length of eyeball(eyeball is
longer than normal) or in some cases occurs due
to medications( sulphonamides, acetazolemide,
over use of antacids) or even due to diseases
such as typhoid, influenza and dehydration

7. clinical features
 Defective vision and eye strain
 Poor vision for distance
 Headache
 Eyeballs prominent with large cornea and pupils

8. diagnosis
 History collection and physical examination
 Slit lamp examination
 Ophthlamoscopy
 Fundus examination shows large pale disc with
myopic crescent

9. Correction of myopia

10.  Myopia corrected with appropriate concave lens
or minus lens

11. hypermetropia

12.  It is a refractory error in which parellel rays of light
are focussed behind the retina resulting in blurred
vision
 This occurs due to developmental variation of
eyeball or may be due to acquired ( posterior
dislocation of lens)
 Patient present with difficulty in reading and doing
close work,strain during reading produces
headache

14.  Hypermetropia corrected with convex lens or
positive lens

15. astigmatism

16.  It is a refractory error in which rays of light are not
bent equally by the cornea in all directions so that
a point of focus is not attained.
 It occurs when curvature of cornea is not perfectly
spherical or there is curvature abnormality of lens
 Patient will have poor vision for both far and near
objects

18. ASTIGMATISM CORRECTION
 Astigmatism corrected with cylindrical lens

19. PRESBIOPIA
 Presbyopia is a condition associated with
the aging of the eye that results in progressively
worsening ability to focus clearly on close
objects. Symptoms include difficulty reading small
print, having to hold reading material farther
away, headache, and eyestrain Different people
will have different degrees of problems.

20. PRESBIOPIA CORRECTION

21. Surgical management of refractory
errors
 LASIK –laser in-situ keratomileusis – most common
type. An extremly thin layer of cornea is peeled back
for laser reshaping and is put back in place.
Procedure is safe less discomfort and rapid recovery
 LASEK- laser epithelial keratomileusis –latest
technology and is used for patients whose cornea is
too flat or too thin for LASIK
 CORNEAL RING IMPLANTS(in-tacs)- implants are
used to flatten cornea. Implants are semicircular or
like cresent, 2 implants are used for each eye and
inserted along sides of cornea
 Hyperopic LASIK and Holmium laser thermoplasty

22. Nursing management
 Assess preoperatively for degree of refractive
eeror
 Surgery done in OPD under local anesthesia
 Eye protection with eye googles
 Vigorous activities and eye make up avoided after
surgery
 Post operative pain – mild analgesics and
steroids to reduce inflammation
 Assess vision of patient postoperatively