1 / 57

Optics

Optics. Professor Damian Czepita Department of Ophthalmology Pomeranian Medical Academy Szczecin, Poland http://sci.pam.szczecin.pl/~czepita. EMMETROPIC EYE. Image: true, reversed, reduced Refraction: cornea 43,5 D lens 19,1 D aqueous humor boundary membrane of the vitreous

william-osborn
Download Presentation

Optics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Optics Professor Damian Czepita Department of Ophthalmology Pomeranian Medical Academy Szczecin, Poland http://sci.pam.szczecin.pl/~czepita

  2. EMMETROPIC EYE • Image:true, reversed, reduced • Refraction: cornea 43,5 D lens 19,1 D aqueous humor boundary membrane of the vitreous vitreous body Total 58,5-64,2 D

  3. NEAR AND FAR POINT • Near point: The closest situated point from where exiting rays of light are refracted on the retina. • Far point: The farthest situated point from where exiting rays of light are refracted on the retina.

  4. RANGE AND AMPLITUDE OF ACCOMMODATION • Range of accommodation: The distance between the far and near point. • Amplitude of accommodation: The range of accommodation in D.

  5. AGE, NEAR POINT,AMPLITUDE OF ACCOMODATION • 10 years7 cm 14 D • 20 years 10 cm 10 D • 30 years 14 cm 7 D • 40 years 22 cm 4,5 D • 50 years 50 cm 2 D • 60 years 100 cm 1 D • 70 years infinite 0 D

  6. PRESBYOPIA • After the 40th year of age: Decrease in elasticity of fibers and capsules of the lens.

  7. SENILE HYPEROPIA • After the 60th year of age: Decrease of the refractive index in eye tissues, especially in the cornea and the vitreous body.

  8. READING GLASSES • 40 years of age +1 D • 50 years of age +2 D • 60 years of age +3 D

  9. CLASSIFICATION OF MYOPIA • AXIAL - too long axis of the eye, normal strength of the optic system • REFRACTIVE – normal length of the eye axis, too strong optic system

  10. CLASSIFICATION OF MYOPIA LOW < -4 D MEDIUM -4 – -8 D HIGH > -8 D

  11. OCCURRENCE OF MYOPIA • Stickler syndrome • Marfan’s syndrome • Ehlers-Danlos syndrome • Weill-Marchesani syndrome • homocystinuria

  12. OCCURRENCE OF MYOPIA • McCune-Albright syndrome • Kniest syndrome • Down syndrome • Prader-Will syndrome • Noonan sydrome

  13. OCCURRENCE OF MYOPIA • Cohen syndrome • Rubinstein-Taybi syndrome • Cornelia de Lange syndrome • fetal alcohol syndrome • Knobloch syndrome

  14. OCCURRENCE OF MYOPIA • congenital night blindness • deficiency of ornithine aminotransferase • deficiency of prolidase • premature infants • lack of a sufficient amount of calcium, fluoride and selenium in food

  15. READING OR WRITING VS. MYOPIAP <0,001

  16. COMPUTER VS. MYOPIAP < 0,01

  17. TELEVISION VS. MYOPIAP > 0,05

  18. INHERITANCE OF MYOPIA • MONOGENIC: autosomal dominant autosomal recessive X-linked • POLYGENIC: < -6 - chromosome 1 ? > -6 – chromosome 1-4, 7, 8, 10-12, 17, 18, 22

  19. CHILDHOOD MYOPIA • is the most often met form of myopia.It occurs before and during maturation.

  20. PROCEDURES IN CHILDHOOD MYOPIA • exercises in plus glasses when looking far away • reading in prisms • temporary usage of spectacles • keeping hygiene of the visual work: correct illumination, reading from a distance of 30 cm, doing breaks during visual work

  21. PROGRESSIVE MYOPIA • develops after birth to the 30-35 years of age. It is characterized by its fast course.

  22. PROCEDURES IN PROGRESSIVE MYOPIA • drugs sealing the vessels and improving circulation: Calcium, Extract vaccinium myrtillus, Pentoxifylline, Rutoside, Xantinol nicotinate • biostimulating drugs: Aloe extract, Extract total eye, Peat bog extract, Placental extract, Sea slime extract • vitamins: A, B1, B2, B6, B12, C, D, E, F, PP • diet with plenty of fresh fruits and vegetables

  23. PROCEDURES IN PROGRESSIVE MYOPIA • permanent usage of spectacles • keeping hygiene of the visual work: correct illumination, reading from a distance of 30 cm, doing breaks during visual work • laser treatment: photocoagulations of degenerative changes in the retina and choroidea

  24. SUBSTANCES INHIBITING THE PROGRESS OF EXPERIMENTAL MYOPIA • PIRENZEPINE - antagonist of the muscarinic M1 receptors, • APOMORPHINE-unselective agonist of the dopamine receptors.

  25. CLASSIFICATION OF HYPEROPIA • AXIAL - too short axis of the eye, normal strength of the optic system • REFRACTIVE - normal length of the eye axis, too low strength of the opticsystem • PHYSIOLOGICAL< +3 D

  26. ASTIGMATISM • A refractive error, which causes rays of light passing through the refractive planes of the eye to be differently refracted.

  27. ORIGINS OF ASTIGMATISM • Corneal astigmatism: deformation in the anterior and posterior surface of the cornea • Lenticular astigmatism: deformation in the anterior and posterior surface of the lens, decentralization of the lens, irregular refractive index of the lens

  28. ORIGINS OF ASTIGMATISM • Corneo-lenticular astigmatism • Others - for examaple deformations of the posterior part of the eyeball

More Related