Optics of human eye

1. OPTICS OF HUMEN EYE 👀
PRESENTED BY
😊ATHIRA K (BSC OPTOM)

2. 1)OPTICAL SYSTEMOF
HUMEN EYE::
2)SCHEMATIC EYE
3)AXES AND ANGLES OF
EYE
1)OPTICAL SYSTEM OF HUMEN
EYE
2)SCHEMATIC EYE
3)AXES AND ANGLES OF EYE

3. HUMEN EYE::
THE HUMAN EYE IS A SENSORY ORGAN, PART OF THE
SENSORY NERVOUS SYSTEM, THAT REACTS TO
VISIBLE LIGHT AND ALLOWS HUMANS TO USE VISUAL
INFORMATION FOR VARIOUS PURPOSES INCLUDING
SEEING THINGS, KEEPING BALANCE, AND
MAINTAINING CIRCADIAN RHYTHM.

5. •HUMANS HAVE TWO EYES, SITUATED ON THE LEFT AND THE RIGHT OF
THE FACE. THE EYES SIT IN BONY CAVITIES CALLED THE ORBITS, IN
THE SKULL. THERE ARE SIX EXTRAOCULAR MUSCLES THAT CONTROL
EYE MOVEMENTS.

9. DIMENSIONS OF AN ADULT EYE BALL:
ANTEROPOSTERIOR DIAMETER=24MM
HORIZONTAL DIAMETER=23.5MM
VERTICAL DIAMETER=23MM
VOLIUME=6.5ML
WEIGHT=7G
CICUMFERENCE=75MM

13. STRUCTURE OF HUMAN EYE:

14. OPTICS OF HUMAN EYE:

16. •THE BASIC OPTIC FUNCTION OF THE EYE IS TO FORM AN IMAGE OF WHATEVER OBJECT
BEING LOOKED AT (FIXATED ON) ON THE RETINA. THIS IMAGE FORMATION IS DONE BY THE
COMBINATION OF THE CORNEA AND THE LENS WHICH BEHAVES LIKE A CONVEX LENS. THE
FOCUS

17. CORNEA::
NORMALCORNEA:::
•PROLATE SHAPE
•ANTERIOR SURFACE OF CORNEA :ELIPTICAL
•HORIZONTAL DIAMETER=11.7MM
•VERTICAL DIAMETER=11MM
• POSTERIOR SURFACE OF CORNEA IS CIRCULAR WITH AVERAGE
DIAMETER OF 11.5MM
• THICKNESS OF CORNEA:::IT VARIES 0.52MM AT CENTRE, 0.8MM
AT PERIPHERY IT VARIES FROM 1-1.2MM
• AVERAGE CORNEAL THICKNESS=540MICROMETER
• ANTERIOR RADIUS OF CURVATURE:7.8MM
• POSTERIOR RADIUS OF CURVATURE=6.5MM
• REFRACTIVR INDEX=1.376
• REFRACTIVE POWER=+43D

18. CRYSTALLINE LENS::
THE LENS IS A TRANSPARENT, BICONVEX,CRYSTALINE STRUCTURE PLACED BETWEEN THE IRIS AND THE
VITREOUS IN A SAVIOR SHAPED DEPRESSION CALLED PATTALLAR FOSSA
DIAMETER=10MM
THICKNESS VARIES WITH AGE:AT BIRTH=3.5MM, AT EXTREME OF AGE=5MM
WEIGHT :0-9 YEARS=135MG, 40-80YEARS OF AGE=255MG
SURFACES::ANTEEIIR SURFACES IS LESS CONVEX THAN POSTERIOR
RADIUS OF CURVATURE ::ANTERIOR -10MM, POSTERIOR =6MM
REFRACTIVE INDEX:1.39(MEAN), 1.38(CORTEX),NUCLEAR-1.41
TOTALREFRACTIVE POWER =+15-16D
ACCOMODARIVE POWER OF THE LENS VARIES WITH AGE ::AT BIRTH=14-16D,25YEARS OF AGE-7-8D , 50
YEARS OF AGE =1-2D

19. VITREOUS HUMOR::
•IT IS A TRANSPARENT, COLORLESS, GEL LIKE SUBSTANCE THAT FILLS
THE SPACE BETWEEN THE LENS AND RETINA WITH IN THE EYE.
•REFRACTIVE INDEX=1.336
•CONSIST OF 99%WATER ,
•VOLUME:ABOUT 3 MY PER EYE.

20. AQUEOUS HUMOUR::
•IT IS A CLEAR LIQUID INSIDE THE FRONT PART OF THE EYE.
•VOLIUME::2MICRO L/M
MANTERIORLY-BACK OF THE CORNEA, POSTERIORLY-ANTERIOR
SURFACE OF IRIS AND CILIARY BODY.
•3MM DEEP

23. OPTICAL SYSTEM OF
HUMEN EYE::

26. SCHEMATIC EYE 👀 ::
•A SCHEMATIC EYE IS A MATHEMATICAL OR PHYSICAL MODEL THAT
REPRESENTS THE BASIC OPTICAL FEATURES OF THE REAL EYE.
•SCHEMATIC EYES HAVE MANY APPLICATIONS, PARTICULAR AS TEACHING
AIDS IN OPTICS, OPTOMETRY, OPHTHALMOLOGY, PSYCHOLOGY (VISION AND
VISUAL PERCEPTION) AND VISUAL ERGONOMICS. BESIDES SHOWING THE
BASIC OPTICAL STRUCTURE OF THE EYE, THE DIMENSIONS AND OTHER
OCULAR PARAMETERS ALLOW ONE TO TRACE RAYS THROUGH THE EYE AND
DETERMINE THE POSITION, SIZE AND ORIENTATION OF IMAGES AND ASSESS
THE ABERRATIONS AND HENCE QUALITY OF THE RETINAL IMAGE.

27. HISTORY ::
•*THE FIRST PHYSICAL MODEL OF THR EYE-”REAL EYE”-CHRISTIAN HUYGENS(1629-1695)
•*SMITH IN 1738,DESCRIBED HUGENS EYE 2 HEMISPHERE, CORNEA&RETINA
•*LE GRAND, MOSTER IN 1844 WAS THE FIRST TO CONSTRUCT A THEORETICAL SCHEMATIC EYE
•*FIRST ACCURATE SCHEMATIC EYE-LISTING, 1851
•*HELMHOLTZ DEVELOPED A MODIFIED VERSION OF LISTING'S EYE
•*TSCHERING PUBLISH A MORE COMPLEX EYE THAT CONTAINED THE POSTERIOR CORNRAL SURFACE, HE
CLAIMED TO MEASURE IT FIRST.
•*ALLVAR GULLSTRAND DEVELOPED A MORE IMPROVED SCHEMATIC EYE WITH FOUR SURFACE LENS AND
EXTRA LENS COMPLEXICITY.
•*GULLSTRAND'S NOBEL PRIZE WINNING WORK-SCHEMATIC EYES BEAR HIS NAME

31. CARDINAL DATA OF THE GULLSTRAND'S
SCHEMATIC EYE::
•*PRINCIPLE FOCI F1 AND F2 LIE 15.7MM IN FRONT AND 24MM BEHIND
THE CORNEA
•*PRINCIPAL POINTS P1 AND P2 LIE IN THE ANTERIOR CHAMBER 1.35MM
AND1.60MM BEHIND THE ANTERIOR SURFACE OF CORNEA
•*NODAL POINT N1 AND N2 LIE IN THE POSTERIOR PART OF LENS 7.08MM
AND 7.33MM BEHIND THE ANTERIOR SURFACE OF CORNEA

33. •THE TOTAL DIOPTRIC POWER OF THIS SCHEMATIC
EYE=58.64D
•REFRACTIVE INDICES:
1. CORNEA-1.376
2.AQUEOUS-1.336
3.LENS CORTEX-1.386
4.LENS CORE-1.406
5.VITREOUS-1.336

34. POSITION OF THE OPTICAL ELEMENTS IN
THE EYE IS::
•ANTERIOR SURFACE OF CORNEA-0MM
•POSTERIOR SURFACE OF CORNEA-0.5MM
•ANTERIOR SURFACE OF LENS-3.6MM
•POSTERIOR SURFACE OF LENS CORE-4.146MM
•POSTERIOR SURFACE OF LENS CORE-6.505MM

35. RADIUS OF CURVATURE OF THE REFRACTIVE
SURFACES:
•ANTERIOR SURFACE OF CORNEA-7.70MM
•POSTERIOR SURFACE OF CORNEA-6.70MM
•ANTERIOR SURFACE OF LENS-10.00MM
•POSTERIOR SURFACE OF THE LENS-6.00MM
•ANTERIOR SURFACE OF THE LENS CORE-7.91MM
•POSTERIOR SURFACE OF THE LENS CORE-5.76MM

36. ANGLES AND AXES OF EYE::

37. •AXES OF THE EYE::
•1)OPTICAL AXIS-THE LINE PASSING THROUGH THR CENTRE OF
CORNEA(P)ABD THR CENTRE OF THE LENS(N),AND MEETS THE
RETINA(R) ON THE NASAL SIDE OF THE FOVEA.
•2)VISUAL AXIS-IT IS THE LINE JOINING THE FIXATION POINT (O),
NODAL POINT(N)AND THE FOVEA(F)
•3)FIXATION AXIS-IT IS THE LINE JOINING THE FIXATION POINT(O)
AND THE CENTRE OF ROTATION(C)

39. •VISUAL ANGLES:::
•ANGLE ALPHA-IT IS THE ANGLE(ONA)FORMED BETWEEN THE OPTICAL
AXIS(AR) AND VISUAL AXIS(OF) AT THE NODAL POINT(N)
•2)ANGLE GAMMA-IT IS THE ANGLE(OCA) BETWEEN THE OPTICAL
AXIS(AR) AND FIXATION AXIS(OC) AT THE CENTRE OF ROTATION OF
THE EYE BALL(C)
•3)ANGLE KAPPA-IT IS THE ANGLE (OPA) FORMED BETWEEN THE
VISUAL AXIS(OF)AND PUPILLARY LINE (AP)