Astigmatism 1122020 1 Definition Astigmatism is defined as

  • Slides: 27
Download presentation
Astigmatism 11/2/2020 1

Astigmatism 11/2/2020 1

Definition Astigmatism is defined as that dioptric condition of the eye in which a

Definition Astigmatism is defined as that dioptric condition of the eye in which a “point” focus is not formed on the retina 11/2/2020 2

Aetiology l Usually the cornea; rarely lens, IOL, etc. l Error in curvature in

Aetiology l Usually the cornea; rarely lens, IOL, etc. l Error in curvature in cornea or lens l Error in centering of lens or IOL l Error in refractive index of lens 11/2/2020 3

Physiological Astigmatism l Vertical corneal meridian is more curved than the horizontal l Seen

Physiological Astigmatism l Vertical corneal meridian is more curved than the horizontal l Seen in children and young adults l Gradually decreases with age l Constant pressure of the upper lid over the globe l In old age-Inverse astigmatism. Horizontal meridian is more curved than the vertical 11/2/2020 4

Types of Astigmatism 11/2/2020 5

Types of Astigmatism 11/2/2020 5

Types of Astigmatism Irregular Astigmatism Mixed Simple Astigmatism Myopic 11/2/2020 Compound Astigmatism Hypermetropic 6

Types of Astigmatism Irregular Astigmatism Mixed Simple Astigmatism Myopic 11/2/2020 Compound Astigmatism Hypermetropic 6

Classification of Astigmatism Regular Astigmatism Oblique Astigmatism With the rule Against the rule 11/2/2020

Classification of Astigmatism Regular Astigmatism Oblique Astigmatism With the rule Against the rule 11/2/2020 Irregular Astigmatism Bi-Oblique Astigmatism 7

Classification of Astigmatism Irregular Astigmatism Bi-Oblique Astigmatism Regular Astigmatism Mixed Astigmatism Compound Astigmatism Simple

Classification of Astigmatism Irregular Astigmatism Bi-Oblique Astigmatism Regular Astigmatism Mixed Astigmatism Compound Astigmatism Simple Astigmatism Regular Astigmatism With the rule 11/2/2020 Against the rule 8

The corneal meridians 11/2/2020 9

The corneal meridians 11/2/2020 9

Variations in the corneal meridians +1 D +2 D +1 D 11/2/2020 10

Variations in the corneal meridians +1 D +2 D +1 D 11/2/2020 10

Types of Astigmatism 11/2/2020 11

Types of Astigmatism 11/2/2020 11

Types of Astigmatism 11/2/2020 12

Types of Astigmatism 11/2/2020 12

Types of regular astigmatism 11/2/2020 13

Types of regular astigmatism 11/2/2020 13

Simple Astigmatism 11/2/2020 14

Simple Astigmatism 11/2/2020 14

Compound Astigmatism 11/2/2020 15

Compound Astigmatism 11/2/2020 15

Mixed and Irregular Astigmatism 11/2/2020 16

Mixed and Irregular Astigmatism 11/2/2020 16

Symptoms l Diminution of vision l Distortion of images l Asthenopia due to accommodative

Symptoms l Diminution of vision l Distortion of images l Asthenopia due to accommodative effort l Headache or brow ache 11/2/2020 17

Optical treatment l Spectacle – Full correction usually – Under-correction if intolerable symptoms l

Optical treatment l Spectacle – Full correction usually – Under-correction if intolerable symptoms l Contact lenses – In small errors- spherical equivalent – In large errors- toric / rigid contact lens 11/2/2020 18

Surgical treatment l Astigmatic keratectomy l Laser refractive surgery 11/2/2020 19

Surgical treatment l Astigmatic keratectomy l Laser refractive surgery 11/2/2020 19

Irregular astigmatism l Treatment is unsatisfactory l Keratoplasty may be required in keratoconus 11/2/2020

Irregular astigmatism l Treatment is unsatisfactory l Keratoplasty may be required in keratoconus 11/2/2020 20

EXAMPLES l Simple Myopic Astigmatism with the rule 11/2/2020 Sph Cyl Axis - -3.

EXAMPLES l Simple Myopic Astigmatism with the rule 11/2/2020 Sph Cyl Axis - -3. 0 D 180 21

l Simple Myopic Astigmatism against the rule 11/2/2020 Sph Cyl Axis - -2. 0

l Simple Myopic Astigmatism against the rule 11/2/2020 Sph Cyl Axis - -2. 0 D 90 22

l Simple Hypermetropic Astigmatism with the rule 11/2/2020 Sph Cyl Axis - +2. 0

l Simple Hypermetropic Astigmatism with the rule 11/2/2020 Sph Cyl Axis - +2. 0 D 90 23

l Simple Hypermetropic Astigmatism against the rule 11/2/2020 Sph Cyl Axis - +1. 5

l Simple Hypermetropic Astigmatism against the rule 11/2/2020 Sph Cyl Axis - +1. 5 D 180 24

l Compound Myopic Astigmatism with the rule 11/2/2020 Sph Cyl Axis -2. 0 D

l Compound Myopic Astigmatism with the rule 11/2/2020 Sph Cyl Axis -2. 0 D -1. 0 D 180 25

l Compound Hypermetropic astigmatism Astigmatism with the rule 11/2/2020 Sph Cyl Axis +2. 0

l Compound Hypermetropic astigmatism Astigmatism with the rule 11/2/2020 Sph Cyl Axis +2. 0 D +1. 0 D 180 26

l Mixed astigmatism 11/2/2020 Sph Cyl Axis +1. 0 D -3. 0 D 180

l Mixed astigmatism 11/2/2020 Sph Cyl Axis +1. 0 D -3. 0 D 180 27

Astigmatism Recognizing the presence of astigmatism When youAstigmatism Recognizing the presence of astigmatism When you
CONDITIONALS 1122020 1 IF CLAUSES 1122020 2 AREALCONDITIONALS 1122020 1 IF CLAUSES 1122020 2 AREAL
dalej 1122020 Joanna Sokalska B P ALETNICA 1122020dalej 1122020 Joanna Sokalska B P ALETNICA 1122020
DEFINED BENEFITSDEFINED CONTRIBUTIONS Defined Benefits A traditional definedDEFINED BENEFITSDEFINED CONTRIBUTIONS Defined Benefits A traditional defined
Textbook definition AI Defined AI may be definedTextbook definition AI Defined AI may be defined
Textbook definition AI Defined AI may be definedTextbook definition AI Defined AI may be defined
The Modes Definition Definition Defined Definitions explain whatThe Modes Definition Definition Defined Definitions explain what
Astigmatism management with toric intraocular lenses in cataractAstigmatism management with toric intraocular lenses in cataract
l Astigmatism is a type of refractive errorl Astigmatism is a type of refractive error
Examination Techniques for Accuracy and Efficiency Astigmatism DetectionExamination Techniques for Accuracy and Efficiency Astigmatism Detection
Correction of Astigmatism with Toric IOL After PreviousCorrection of Astigmatism with Toric IOL After Previous
Evaluation of C Limbal Relaxing Incisions for AstigmatismEvaluation of C Limbal Relaxing Incisions for Astigmatism
Correction of Myopia and Myopic Astigmatism with PosteriorCorrection of Myopia and Myopic Astigmatism with Posterior
ASCRS Boston 2010 Residual astigmatism after multifocal IOLASCRS Boston 2010 Residual astigmatism after multifocal IOL
CENTURION UNIVERSITY OF TECHNOLOGY AND MANAGEMENT ASTIGMATISM ANDCENTURION UNIVERSITY OF TECHNOLOGY AND MANAGEMENT ASTIGMATISM AND
REFRACTIVE ERRORS MYOPIA HYPEROPIA ASTIGMATISM January 15 2014REFRACTIVE ERRORS MYOPIA HYPEROPIA ASTIGMATISM January 15 2014
Comparing Factors Affecting Surgically Induced Astigmatism After PhacoemulsficationComparing Factors Affecting Surgically Induced Astigmatism After Phacoemulsfication
Astigmatism spherical aberration contrast vision and defocus ofAstigmatism spherical aberration contrast vision and defocus of
Astigmatism correction methods Alireza Peyman MD http wwwAstigmatism correction methods Alireza Peyman MD http www
Femtosecond LaserAssisted Astigmatic Keratotomy for Naturally Occurring AstigmatismFemtosecond LaserAssisted Astigmatic Keratotomy for Naturally Occurring Astigmatism
Astigmatism in H First measurements on the IRTCAstigmatism in H First measurements on the IRTC
Kerrlens Mode Locking Without Nonlinear Astigmatism Shai YefetKerrlens Mode Locking Without Nonlinear Astigmatism Shai Yefet
Astigmatic Refractive Error Types of Astigmatism Basic OpticsAstigmatic Refractive Error Types of Astigmatism Basic Optics
Management of Corneal Astigmatism with Toric IOLs OptimizingManagement of Corneal Astigmatism with Toric IOLs Optimizing