Process of seeing pdf

this power point is help in continuing teacher traning in special education

1. Process
of
Seeing
Chandan Kumar Dubey
Assistant Professor
LKC Shri Jagdamba Andh
Vidyalaya
Shri Ganganagar(Rajasthan)

2. Process of Seeing
•आँखहमारेशरीरकामहत्वपूर्णअंगहैजिसकीसहायतासे
हमयहस ंदरसंसारदेखतेहैं।आँखऔरफोटोग्राफफक
कै मरेकीबनावटमेंबह तसीसमानताएँहैं।फोटोग्राफफक
कै मरेमेंजिसतरहउत्तललैंसद्वारासामनेजथितवथत का
उल्टाप्रततबबम्बफफल्मपरबनताहैउसीतरहहमारीआँख
मेंकोशशकाओंसेबनाउत्तललैंसहोताहै,िोहमारीआँख
केसामनेजथितवथत काउल्टाप्रततबबम्ब‘रेटटना’पर
बनाताहै।हमारीआँखकाआकारछोटीगोलगेंदकीतरह
होताहै।आँखकोशशकाओंसेबनेलैंसकीफोकसदूरीमें
अवश्यकतान सारपररवतणनकरपासवदूरकीवथत ओंको
थपष्टदेखसकतीहै।

3. मानव नेत्र के मुख्य भाग (Parts of Human Eye)
•दृढपटल(Sclera):यहमाँसपेशशयोंसेबनाश्वेतअपारदशीभागहोताहै,िोनेत्रकेगोलेकोढँके
रहताहैतिाइसकीस रक्षाकरताहै।इसेश्वेतपटलभीकहतेहैं।
•कार्निया(Cornea):यहदृढ़पटलकेसामनेउभराह आपारदशीभागहोताहै,जिसमेंहोकरप्रकाशनेत्र
मेंप्रवेशकरताहै।यहनेत्रकीस रक्षाकरनेकेसाि-सािक छहदतकप्रकाशकोफोकसकरनेमें
मददकरताहै।
•आइरिस(Iris):आइररसआंखकावह‍टहथ‍साहैजिसमेंरंगहोताहै।आइररसकातनणयाकेपीछेएकपदाण
होताहै।इसकारंगववशभन्नव्यजततयोंएवंदेशवाशसयोंकेशलएशभन्न-शभन्नहोसकताहै|और
आईबॉलमेंप्रवेशप्रकाशकीमात्राकोतनयंबत्रतकरनेकाकामकरताहै|
•पुतली(Pupil):आइररसकेमध्यएकछोटासातछद्रहोताहैजिसेप तलीकहतेहैं।
•नेत्रलैंस(EyeLens):प तलीकेपीछेनेत्रलैंसशसशलयरीमाँसपेशशयोंद्वाराअपनीजथिततमेंबनारहता
है।नेत्रलैंसववशभन्नप्रकारकीिीववतकोशशकाओंसेबनीएकपारदशीझिल्लीकीतरहहोताहै।

4. Continued
•ससलयिीमााँसपेसियााँ:श्वेतपटलकेउभरेह एभागकेिोड़सेमाँसपेशशयाँलटकतीरहतीहैंजिनकेमध्यनेत्रलैंसलटकारहताहै।येमाँसपेशशयाँलैंस
परदाबडालकरउसकीफोकसदूरीकोकमयाज्यादाकरसकतीहैं।
•नेत्रोद:कातनणयाऔरनेत्रलैंसकेबीचएकपारदशीद्रवभराहोताहै।इसेनेत्रोदकहतेहैं।
•िेटटना:यहएकस ग्राहीपारदशीझिल्लीहोतीहै,जिसपरअनेकप्रकाशसंवेदीतंबत्रकाएँहोतीहैं।इनतंबत्रकाओंकासंबंधमजथतष्कसेहोताहै।िब
येतंबत्रकाएँरेटटनापरबनेप्रततबबम्बकेसंके तोंकोमजथतष्कमेंभेितीहैंतोवेउसेसीधाकरदेतीहैं।अत:मजथतष्करेटटनापरबनीवथत केउल्टे
प्रततबबम्बकोसीधाअन भवकरताहै।
•कॉचाभद्रव:नेत्रलैंसऔररेटटनाकेमध्यएकपारदशीद्रवभराहोताहै,जिसेकॉचाभद्रवकहतेहैं।सामान्यदृजष्टवालेव्यजततदूरएवंपासकी
वथत ओंकोथपष्टदेखसकतेहैं।ऐसेव्यजततयोंकेनेत्रोंमेंकोईदोषनहींपायािाताहै,परन्त बढ़तीह ईउम्रयाअन्यकारर्ोंसेमन ष्यकीआँख
मेंक छदोषउत्पन्नहोिातेहैं,जिनकेकारर्वहपासयादूरजथितवथत ओंकोयादोनोंतरहकीवथत ओंकोनहींदेखपाताहै।इनदोषोंकोदूर
करनेकेशलएअवतलयाउत्तललैंसयादोनोंलैंसोंसेबनेचश्मेकाउपयोगकरतेहैं।
•ऑप्टटकनविस: ऑजटटक‍नवणस‍में‍एक‍लाख‍से‍अधधक‍नवणस‍फाइबर‍होते‍हैं‍िो‍रॉड्स‍और‍कोन्‍स‍से‍संकेत‍लेकर‍उसे‍मजथतष्‍क‍भेि‍देते‍हैं‍िहां‍वह‍
छववयों‍से‍शमलकर‍एक‍फफल्म‍में‍पररवततणत‍हो‍िाते‍हैं‍जिसे‍मोटे‍तौर‍पर‍मानव‍दृजष्ट‍के‍रूप‍में‍िाना‍िाता‍है।

5. Function of Eye
•Therearemanydifferentpartsoftheeyethathelptocreatevision.
•आंखकेकईअलग-अलगटिस्सेिैंजोदृप्टटबनानेमेंमददकितेिैं।
•Lightpassesthroughthecornea,theclear,dome-shapedsurfacethatcoversthefrontoftheeye.
•प्रकािकॉर्निया,स्पटट,गुंबदकेआकािकीसतिसेगुजितािैजोआंखकेसामनेकोकविकितािै।
•Thecorneabends-orrefracts-thisincominglight.Theiris,thecoloredpartoftheeye,regulatesthesizeofthepupil,theopeningthatcontrolstheamountof
lightthatenterstheeye.
•कॉतनणयाि कताहै-याअपवतणक-यहआनेवालीरोशनी।आईररस,आंखकारंगीनटहथसा,प तलीकेआकारकोतनयंबत्रतकरताहै,उद्घाटनिोआंखमें
प्रवेशकरनेवालेप्रकाशकीमात्राकोतनयंबत्रतकरताहै।
•Behindthepupilisthelens,aclearpartoftheeyethatfurtherfocuseslight,oranimage,ontotheretina.
•पुतलीकेपीछेलेंसिै,आंखकाएकस्पटटटिस्साजोआगेिेटटनापिप्रकाि,याएकछववकोकेंटद्रतकितािै।
•Theretinaisathin,delicate,photosensitivetissuethatcontainsthespecial“photoreceptor”cellsthatconvertlightintoelectricalsignals.
•िेटटनाएकपतली,नाजुक,सिजऊतकिैप्जसमेंवविेष"फोटोरिसेटटि"कोसिकाएंिोतीिैंजोप्रकािकोववद्युतसंके तोंमेंपरिवर्तितकितीिैं।

6. Continued
•Theseelectricalsignalsareprocessedfurther,andthentravelfrom
theretinaoftheeyetothebrainthroughtheopticnerve,abundle
ofaboutonemillionnervefibres.
•इनववद्य तसंकेतोंकोआगेसंसाधधतफकयािाताहै,औरफफरआंखकेरेटटनासे
ऑजटटकतंबत्रका,लगभगएकशमशलयनतंबत्रकातंत ओंकेएकबंडलकेमाध्यमसे
मजथतष्ककीयात्राकीिातीहै।
•We“see”withourbrains;oureyescollectvisualinformationand
beginthiscomplexprocess.
•हमअपनेटदमागकेसाि"देखतेहैं";हमारीआँखेंदृश्यिानकारीएकत्रकरतीहैं
औरइसिटटलप्रफियाकोश रूकरतीहैं।

7. 3.2 Blindness and LowVision-
Definition andClassification

8. VisualImpairment

9. What is it like to be visuallyimpaired?

10. Corrected Visual
Acuity in thebetter
eye
WHO’sDefinition
(Standard)
WorkingDefinitionIndianDefinition
6/6-6/18 Normal Normal Normal
<6/18-6/60 VisualImpairment LowVision LowVision
<6/60-3/60 SevereVisual
Impairment
LowVision Blind
<3/60-1/60 Blind LowVision Blind
<1/60-PL Blind LowVision Blind
NPL Blind Total Blindness Total Blindness

11. Visual Impairment
•VisualImpairment:VisualImpairmentfallsunderPhysicals/Sensory
Disability.
•Avisualimpairmentreferstowhenyoulosepartorallofyourability
tosee(vision).Theimpairmentmustpersistevenwiththeuseof
eyeglasses,contactlenses,medication,orsurgery.

14. Types of VisualImpairment
According to PWD Act 1995
Blindness : It refersto a condition where a person suffers from any of the following conditions,
namely:
Total absence of sight;or
Visual acuity not exceeding 6/60 or 20/200(Snellen) in the better eye even with correction
lenses; or
Limitation of the field of vision subtending an angle of 20 degree orworse.
According to RPWD Act 2016
Blindness : It refersto a condition where a person suffers from any of the following conditions,
after best correction namely:
Total absence of sight;or
Visual acuity less than 3/60 or less than 10/200(Snellen) in the better eye even with best
possible correction lenses; or
Limitation of the field of vision subtending an angle of 10 degree orworse.

15. Low Vision: The Persons with Disabilities Act,
1995 also recognizes low vision as a category of
disability and defines it asfollows:
“Person with low vision” means a person with impairment
of visual functioning even after treatment or standard
refractive correction but who uses or is potentiallycapable
of using vision for the planning or execution of a taskwith
appropriate assistivedevice”.

16. Low Vision: The Right to Persons with Disabilities
Act, 2016 also recognizes low vision as a category
of disability and defines it asfollows:
“Low-Visionmeans condition where a person has any of the
following conditions:-”.
Visual acuity not exceeding 6/18less than 20/60 upto 3/60
upto/10/200(Snellen) in the better eye with best possible
corrections
Limitation in the field of vision subtending an angle of less
than 40 degree up to 10 degree

17. The Standard WHO definition is used in medical
reports and publications and is solely based on visual
acuity and does not take into account functional
vision.

18. •TheWHOstandarddefinitiondefines
Blindnessasvisualacuityoflessthan3/60inthebetter
eyewiththebestcorrectionsascomparedtothatof6/60
inIndia.
TheWHOfunctionaldefinition,however,considers
blindnessstartingatlightperceptionorwhenapersonhas
nousablevision.

19. Similarly,
A person with visual acuity better than 3/60
but equal or less than 6/60 is graded as
“Blind” in India, while WHO grades him as
lowvision.

20. •In India, A person with Visual Acuity is less than 6/60
is legally blind, which enables to receive certain
services and financialbenefits.
However, a person with legal blindness can still have
useful vision to do certain tasks, as can be seen in the
workingdefinition.
•This refers to the fact that they still have functional
vision, which is the use of vision for a particular
purpose.

21. The WHO working definition of Low Vision(WHO,1992) is asfollows:
“A person with low vision is one who has impairment of visual
functioning even after treatment, and/ orstandard refractive
correction, and has a visual acuity of less than 6/18 to light
perception or a visual field of less than 10 degrees from the
point of fixation, but who uses, orispotentially able to use,
vision for theplanningand/or execution of a task”.

23. Characteristics of Visual Impairment
•Generally, has the same academic ability as
their peers
•Tends to perform poorly in mathematics
•Appears "clumsy," especially in new situation
•Holds head in awkward position / holds
objects in peculiar position to look at them
•Constantly asks neighbour to tell him / her,
what is going on
•Exhibits poor self -concept
•Less effective use of gestures
•Uses less of lip movement to articulate sounds
•Rubs eyes excessively
•Blinks more than usual
•Squints eyelids together / frowns
•Inflamed / watery eyes
•Recurring styes
•Eyes itch / burn
•Cannot see well
•Dizziness, headaches, or nausea
•Blurred or double vision
•Difficulty in orientation
•Difficulties in object manipulation
•Has difficulty in reading or work requiring
close use of eyes

25. Educational Implication of Visual Impairment
Visualimpairmentwhenpresentfrombirthwillhavemoreimpactonlearningthanvisual
impairmentthatisacquiredlaterinlife.Somemayhavelowordistortedvisionwhileothers
mayhavenovisionatall.ChildrenwithVisualimpairmentareusuallyauditorylearners.They
alsolearnthroughtouchandbypracticallydoingatask.Typeofassistancerequiredfor
learning,willvaryaccordingtothedegreeandnatureoftheirimpairment.
•Difficultyinlearningwhenlongpassagesarereadandfromvisualinputs.
•TakingmoretimetointerpretmeaningasreadingonBraillemode,requireslongertimeand
involveshigherdegreeofmemorizingandsynthesizingfromwholenessofphrases,sentencesetc.
•Difficultyincomprehendingfromverbalcontent,includinggeographicaltermsandconcepts,like
-latitude,longitudes,physicaldirectionsetc.
•Graphicandvisualdescriptionslikemap-reading,graphs,diagrams,paintings,inscriptions,
symbolsandmonumentalarchitecture.

26. Continued
•Poorinobservingenvironmentandspace-land,climate,vegetationandwildlife,distributionof
resourcesandservices.
•Poorindevelopingspatialconceptsandunderstandingtherelationshipsbetweenspatialconcepts.
•Poorunderstandingofthree-dimensionalobjectstransformedintotwodimensionalforms.
•Difficulty in understanding special characters (symbols) used in Mathematics.
•Difficulty in audio recording of mathematical text, for eg., equations, formulas etc.
•Difficulty in transcribing and reading mathematical text in Braille because of spatial arrangement
and colourcodes.
•Difficulty in learning of Nemeth or any other Mathematical Braille Code.
•Difficulty in comprehending abstract concepts.
•Difficulty in comprehending science experiments, especially in Chemistry.
•Require longer time for performing academic tasks.