refractive errors and management

1. REFRACTIVE ERRORS
AND HOW TO
CORRECT THEM
Dr Solanki Optometry Department

2. Refractive Errors
 Emmetropia
 Ametropia
A. Hyperopia
B. Myopia
C. Astigmatism
 Presbyopia
 Aphakia

3. Emmetropia
 The emmetropic eye is normal eye
 Emmetropic eye parallel rays of light come to
focus on the retina

4. Ametropia
Ametropia (Refractive error)
Mismatch between axial length and refractive
power Parallel light rays don’t fall on the retina
(no accommodation)
 Hyperopia { hypermetropia }
 Myopia
 Astigmatism

5. Hyperopia {Hypermetropia}
 The parallel rays coming from infinity focus at
point behind the retina( unaccommodative
eye)
 Axial hyperopia
 Curvature hyperopia
 Latent hyperopia
 Manifest hyperopia
 Absolute hyperopia

6. To Understand
 A 32 year old man have vn of 6/18
 With+ 1.00 D improves vn 6/6(Absolute
hyperopia)
 If an additional+1.50D patient can still see 6/6
(manifest hyperopia)
 With cycloplegic +3.50D vn 6/6
 So 1.00D is latent

7. Symptoms and treatment
 Young may not cause symptoms
 Eye strain
 Headaches
 Earlier presbyopia
 On demand to correct with convex lenses
 Spectacle
 Contact lens
 Surgery

8. Myopia
 Is near-sightedness is that condition on in
which parallel rays of light come to focus at
point just in front of the retina
 Axial myopia
 Curvature myopia
 Index myopia

9. Symptoms And Treatment
 Inability to see objects clearly at distance
 Squeeze eyes
 Burning sensation
To correct with concave lens
 Spectacle
 Contact lens
 Surgery

10. Astigmatism
 Astigmatism is the condition in which rays of
light are not refracted equally in all directions
so that point focus on the retina is not attained
 Regular astigmatism
 Irregular astigmatism

11. Regular Astigmatism
 Regular astigmatism is that refractive condition
in which the axes of the principal meridians of
the astigmatism are right angles to each other.
Types:
• Simple Astigmatism
• Simple Hyperopic / Myopia Astigmatism
• Compound Hyperopic / Myopic Astigmatism
• Mixed Astigmatism

12. Regular Astigmatism Types

13. Irregular Astigmatism
 It is a refractive condition in which excess of
the principal meridian are not right angle to
each other.
 If the cornea has damaged by Trauma or
inflammation or scar tissue.
 Irregularity of the corneal surface.

14. Symptoms and treatment
 Blurred vision
 Eye strain
 To correct with concave/convex cyl
 Spectacle
 Contact lens
 Surgery

15. Presbyopia
 Everyone becomes presbyopic with age
 Decreases accommodative ability of the ciliary
muscle

16. Symptoms and treatment
 Inability to do near work
 Some patient complain that they have to hold
the print farther away
 Fatigue
 Trouble with Threading a needle
 To correct with convex lens
 Spectacle
 Contact lens

17. Visual Age consideration for
Presbyopic
 At the ages 42 to 45----+1.00D to +1.25D
 At the ages 45 to 50----+1.50D to +1.75D
 At the ages 50to 65----+2.00D to +3.00D

18. Aphakia
 Is a condition in which the crystalline lensis
absent from the eye
 May be caused by removal of cataract lens or
displacement of the lens
 To correct with convex lens
 Spectacle
 Contact lens
 Surgery

19. Kept in mind
 The optical centers
must be exact
 Vertex distance
 Lanticular aphakic
lens
 The frame must fit
comfortably on the
nose and to b set
straight

20. THANK YOU