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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

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Optics

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  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

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