IT INCLUDES COMPREHENSIVE SLIDES ON #MYOPIA #HYPEROPIA #ASTIGMATISM #PRESBYOPIA

1. REFRACTIVE ERRORS
PRESENTED BY
USMAN ABDUL
RAZZAQ

2. REFRACTIVE ERRORS
IT INCLUDES
1- MYOPIA
2- HYPEROPIA
3- ASTIGMATISM
4- PRESBYOPIA

3. MYOPIA
ALSO KNOWN AS
NEARSIGHTEDNESS
IN THIS CONDITION, WHEN CILIARY
MUSCLES ARE COMPLETELY
RELAXED, THE LIGHT RAYS
COMING FROM FARTHER OBJECTS
ARE FOCUSED IN FRONT OF THE
RETINA

4. HOW IS MYOPIA DIAGNOSED?
1- As part of the testing, you will identify
letters on a distance chart. This test
measures visual acuity, which is written as a
fraction, such as 20/40.
2- Using an instrument called a phoropter

5. TREATMENT OF MYOPIA
BY USING CONCAVE LENSE BY USING CONTACT LENSE

6. LASER TREATMENT OF MYOPIA
LASIK (laser in situ
keratomileusis)
LASIK removes tissue from the
inner layers, but not from the
surface, of the cornea.
PRK (photorefractive
keratectomy)
In PRK, a laser removes a thin
layer of tissue from the surface
of the cornea in order to change
its shape and refocus light
entering the eye.

7. HYPEROPIA
ALSO KNOWN AS
FARSIGHTEDNESS
IN THIS CONDITION
PARALLEL LIGHTS RAYS ARE
NOT BENT SUFFICIENTLY BY
THE RELAXED LENS SYSTEM
TO COME TO FOCUS BY THE
TIME THEY REACH THE
RETINA

8. HOW IS HYPEROPIA IS
DIAGNOSED?
1- As part of the testing, you will identify letters
on a distance chart. This test
measures visual acuity, which is written as a
fraction, such as 20/40.
2- Using an instrument called a phoropter

9. TREATMENT OF MYOPIA
BY USING CONVEX LENSE BY USING CONTACT LENSE

10. LASER TREATMENT OF MYOPIA
LASIK (laser in situ
keratomileusis)
LASIK removes tissue from the
inner layers, but not from the
surface, of the cornea.
PRK (photorefractive
keratectomy)
In PRK, a laser removes a thin
layer of tissue from the surface
of the cornea in order to change
its shape and refocus light
entering the eye.

11. ASTIGMATISM
IT IS A REFRACTIVE ERROR OF THE
EYE THAT CAUSES THE VISUAL
IMAGE IN ONE PLANE TO FOCUS AT
A DIFFERENT DISTANCE FROM THE
OF PLANE AT RIGHT ANGLES

12. CAUSES OF ASTIGMATISM
1- ANATOMICAL
IMPERFACTION IN THE SHAPE
OF CORNEA
2- A scar in the cornea, resulting
from an injury or infection, or a
disease called keratoconus

13. SYMPTOMS OF ASTIGMATISM
1- EYE STRAIN
2- EYE FATIGUE
3- SQUINTING
4- HEADACHE
5- BLURRING AND DISTORTION OF VISION
AT ALL DISTANCE

14. TYPES OF ASTIGMATISM
1- MYOPIC ASIGMATISM
2- HYPEROPIC ASTIGMATISM
3- COMPOUND ASTIGMATISM

15. HOW ASTIGMATISM IS MEASURED?
1- BY USING PARALLEL BLACK
BARS
2- BY USING KERATOMETER
3- BY USING CORNEAL
TOPOGRAPHER

16. TREATMENT OF ASTIGMATISM
BY USING CYLINDRICAL LENSES BY USING CONTACT LENSE

17. LASIK SURGERIES FOR
ANTISTIGMATISM
LASIK can fully correct astigmatism, and the effect is permanent.

18. PRESBYOPIA
Presbyopia is the normal loss of
near focusing ability that occurs
with age. Most people begin to
notice the effects of presbyopia
sometime after age 40, when they
start having trouble seeing small
print clearly — including text
messages on their phone.

19. ACCOMODATION
FOLLOWING CHANGES OCCUR DURING
ACCOMODATION
1- PUPIL CONSTRICT
2- CONVERGENCE OF EYES
3- LENSE BECOME GLOBULAR
4- CILIARY MUSCLE CONTRACT

20. TREATMENT FOR PRESBYOPIA
1- BY USING BIFOCAL EYEGLASSES
2- BY USING CONTACT LENSES
3- BY DOING REFRACTIVE SURGERIES

21. LASIK VS PRK LASER SURGERIES

22. UA RAZZAQ