Refractive error types of refractive error cause test treatment

1. REFRACTIVE
ERROR
BY SUJIT KUMAR

2. EMMETROPIA When a parallel rays of light coming from infinity (with
Accommodation at rest) are focused either in front or behind the
sensitive layer of retina in one both the meridians (Normal Eye)

3. AMETROPIA
When a parallel rays of light coming from
infinity (with Accommodation at rest) are
focused either in front or behind the sensitive
layer of retina in one both the meridians
(REFRACTIVE ERROR)

4. ETYMOLOGY OF
REFRACTIVE
ERROR
CURVATURE OF CORNEA :- INCREASE
REFRACTIVE INDEX :- INCREASE
AXIAL LENGTH :- ENOBRETION OF EYEBALL
CONGENITAL :- IT MAY BE CONGENITAL
AQURED :- USE MORE THAN NEAR VISION
DECREASE
HEREDITARY :- COMES FROM PARENTS
MORE THAN-6
TROMA ;- IT CAN BE TROMA
POSITION OF LENS

5. HYPERMETROPIA
(LONG SIGHTEDNESS)
When a parallel rays of light coming from infinity
are focused behind the retina with accommodation
being at rest.
इसमें क्या होता है कसी भी Object का Image Retina पर
ना बनकर Beond the Retina क
े पीछे बनती है

6. CAUSES
लेंस पहला होने क
े कारण
Eyeball का साइज कम होना
लेंस का फोकल लेंथ बढ़ जाना
इसमें Far Point साफ दखाई देगी ले कन
Near Object साफ नहीं दखाई देगी

7. Treatment
इसमें Convex Lens का प्रयोग
करेंगे
+ image Converging
Contact Lens
Refractive Surgery

8. MYOPIA (SHORT
SIGHTEDNESS)
When a parallel rays of light coming from infinity
are focused In Front of the retina with
accommodation being at rest.
इसमें क्या होता है कसी भी Object का Image Retina पर
ना बनकर Infront of Retina क
े आगे बनती है

9. CAUSES
लेंस मोटा होने क
े कारण
Eyeball का साइज बढ़ जाना
लेंस का फोकल लेंथ कम हो जाना
इसमें Near Point साफ दखाई देगी ले कन
Far Object साफ नहीं दखाई देगी

10. Treatment
इसमें Concave Lens का प्रयोग
करेंगे
- image Diverging
Contact Lens
Refractive Surgery

11. ASTIGMATISM
Astigmatism is a common vision problem
caused by an error in the shape of the
cornea wherein the refraction various in
the different meridians of the eye .The rays
of light entering the eye cannot converge
to a point of focus but form of focal lines

12. TYPES OF ASTIGMATISM
IRREGULAR
REGULAR

13. SIMPLE ASTIGMATISM :- The rays are focused on the
retina one meridian and either in front myopic.
COMPOUND ASTIGMATISM :- The rays of light in both
meridians are focused either in front and behind the retina
Hypermetropic Astigmatism.
MIXED ASTIGMATISM :- One is mypic another is
Hypermetropic

14. ANISOMETROPIA The optical state with unequal refraction in the two eye is termed
Isometropia
A difference 2.5 D in two eyes 5% up to retinal images-

15. ANISEIKONIA
The image projected to the
visual cortex from two
retina are abnormally
Unequal in Size or Shape.