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ACCOMMODA
TION
PRESENTED BY : SWATI PANARA
FROM : BHARTIMAIYA COLLEGE OF
OPTOMETRY
3rd YEAR 5th SEMESTER
ACCOMMODATION
 An emmetropic eye , parallel rays of light coming from
infinity are brought to focus on the retina , with
...
STIMULUS FOR ACCOMMODATION
• Apparent size for distance of object
• Chromatic aberration
• Blurred retinal image
• oscilla...
TERMS
 Far point of accommodation
 It is the farthest point at which object can be
seen clearly with minimum accommodati...
 Range of accommodation
 It is the distance between far point and near
point of accommodation
 a = r- P
 Amplitude of ...
• In a emmetropic eye , far point is at infinity.
• In a hypermetropic eye far point is virtual and
lies behind the eye.
• In a myopic eye , far point is real and lies in
front of the eye.
DEPTH OF FIELD
• The range of distance from the eye in which an
object appears clear without change of
accommodation is te...
DEPTH OF FOCUS
• THE RANGE AT THE RETINA ON WHICH
AN OPTICAL IMAGE MAY MOVE
WITHOUT IMPAIRED OF Clarity IS
TERMED AS DEPTH...
PATHWAY OF ACCOMMODATION
MECHANISM OF ACCOMMODATION
• Some fish retract their lenses to focus on
distant object.
• Snakes and frogs have mechanism ...
MECHANISM
Changes during accommodation:
(A), contraction of ciliary
muscles; (B), approximation of
ciliary muscles to lens...
REACTION TIME
“ far-to-near” accommodation - 0.64 sec
 “near-to-far” accommodation - 0.56 sec
Contraction of the pupil ...
ANOMALIES OF ACCOMMODATION
DIMINISHED
ACCOMMODATION INCREASED
ACCOMMODATION
DIMINISHED ACCOMMODATION
PHYSIOLOGICAL PHARMACOLOGICAL PATHOLOGICAL
PHYSIOLOGICAL
PRESBYOPIA :::
 Presbyopia = “old man’s eye”
 It is not an error of refraction but a condition
of physiol...
TYPES OF PRESBYOPIA
INCIPIENT
PRESBYOPIA
FUNCTIONAL
PRESBYOPIA
ABSOLUTE
PRESBYOPIA
PREMATURE
PRESBYOPIA
NOCTURNAL
PRESBYOP...
• (1) incipient presbyopia
 The beginning of presbyopia
 (2)functional presbyopia
 When it disturbs the visual function...
• (4) premature presbyopia
At an early age
• (5) nocturnal presbyopia
Decrease amplitude of accommodation in dim
light.
SYMPTOM
DIFFICULTY IN NEAR VISION
ASTHENOPIC SYMPTOM
INTERMITTENT DIPLOPIA
TREATMENT
OPTICAL
SURGICAL
PATHOLOGICAL ACCOMMODATION
INSUFFICIENCY OF
ACCOMMODATION
ILL – SUSTAINED
ACCOMMODATION
INERTIA OF
ACCOMMODATION
PARALYSIS...
INSUFFICIENCY OF ACCOMMODATION
• It is used when the accommodative power is
significantly less than the normal physiologic...
CLINICAL FEATURES
• Headache & fatigue
• Blurred vision for near
• Irritability of the eye
• Accommodative failure & conve...
TREATMENT
o Treatment of the cause
o Near vision spectacle
o Accommodation exercise
ILL SUSTAINED ACCOMMODATION
• It is a condition of accommodation fatigue
refers to a situation in which although the
range...
 CAUSES:
• Asthenopic symptoms
• Ill health
• Uncorrected refractive error
• Over work & emotional stress
 TREATMENT
• C...
ACCOMMODATION INERTIA
• It is a condition in which there is difficulty in
adjusting the accommodation according to the
dis...
TREATMENT
• Correct any refractive error.
• Practise of any accommodation exercise.
PARALYSIS OF ACCOMMODATION
• Paralysis of accommodation also known as
cycloplegia refers to complete absence of
accommodat...
TREATMENT
• Self recovery occurs in drug induced paralysis
and in diphtheric cases { once the systemic
disease is treated}...
INCREASED ACCOMMODATION
EXCESSIVE
ACCOMMODATION SPASM OF
ACCOMMODATION
EXCESSIVE ACCOMMODATION
• The term excessive accommodation is used to
describe a situation in which an individual
exerts m...
CAUSES
 young hypermetropes
Young myopes
Astigmatic error
Presbyopes
Use of improper spectacle
CLINICAL FEATURES
• Varying degree of blurred vision due to
induced pseudo myopia
• Asthenopic symptoms
• Both the far poi...
TREATMENT
Optical
treatment
General
treatment
SPASM OF ACCOMMODATION
• It refers to exertion of abnormally excessive
accommodation which is out of the voluntary
control...
CLINICAL FEATURES
• Varying blurred vision due to induced
pseudomyopia
• Asthenopic symptom
• Headache and browache are ty...
TREATMENT
Relaxation of
ciliary muscle
optical
general
Accomodation
Accomodation
Accomodation
Accomodation
Accomodation
Accomodation
Accomodation
Accomodation
Accomodation
Accomodation
Accomodation
Accomodation
Accomodation
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Accomodation

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Accomodation

  1. 1. ACCOMMODA TION PRESENTED BY : SWATI PANARA FROM : BHARTIMAIYA COLLEGE OF OPTOMETRY 3rd YEAR 5th SEMESTER
  2. 2. ACCOMMODATION  An emmetropic eye , parallel rays of light coming from infinity are brought to focus on the retina , with accommodation at rest.  Our eyes have been provided with a unique mechanism by which we can even focus the diverging rays coming from a near object on the retina in a bid to see clearly.  This mechanism is called accommodation.
  3. 3. STIMULUS FOR ACCOMMODATION • Apparent size for distance of object • Chromatic aberration • Blurred retinal image • oscillation of accommodation • Scanning movement of the eye.
  4. 4. TERMS  Far point of accommodation  It is the farthest point at which object can be seen clearly with minimum accommodation  It is also called punctum remotum  Near point of accommodation  It is the nearest point at which object can be seen clearly with maximum accommodation It is also called punctum remotum
  5. 5.  Range of accommodation  It is the distance between far point and near point of accommodation  a = r- P  Amplitude of accommodation  The difference between dioptric power needed to focus near and to focus far object  A= P-R
  6. 6. • In a emmetropic eye , far point is at infinity.
  7. 7. • In a hypermetropic eye far point is virtual and lies behind the eye.
  8. 8. • In a myopic eye , far point is real and lies in front of the eye.
  9. 9. DEPTH OF FIELD • The range of distance from the eye in which an object appears clear without change of accommodation is termed as depth of field
  10. 10. DEPTH OF FOCUS • THE RANGE AT THE RETINA ON WHICH AN OPTICAL IMAGE MAY MOVE WITHOUT IMPAIRED OF Clarity IS TERMED AS DEPTH OF FOCUS.
  11. 11. PATHWAY OF ACCOMMODATION
  12. 12. MECHANISM OF ACCOMMODATION • Some fish retract their lenses to focus on distant object. • Snakes and frogs have mechanism to move the lens forward for near vision. • In man the process of accommodation is achieved by a change in the shape of the lens.
  13. 13. MECHANISM Changes during accommodation: (A), contraction of ciliary muscles; (B), approximation of ciliary muscles to lens; (C), relaxation of suspensory ligament; (D), increased curvature of anterior surface of lens.
  14. 14. REACTION TIME “ far-to-near” accommodation - 0.64 sec  “near-to-far” accommodation - 0.56 sec Contraction of the pupil - 0.26 to 0.30 sec Convergence response - 0.20 sec
  15. 15. ANOMALIES OF ACCOMMODATION DIMINISHED ACCOMMODATION INCREASED ACCOMMODATION
  16. 16. DIMINISHED ACCOMMODATION PHYSIOLOGICAL PHARMACOLOGICAL PATHOLOGICAL
  17. 17. PHYSIOLOGICAL PRESBYOPIA :::  Presbyopia = “old man’s eye”  It is not an error of refraction but a condition of physiologic insufficiency of accommodation leading to a progressive fall in near vision.
  18. 18. TYPES OF PRESBYOPIA INCIPIENT PRESBYOPIA FUNCTIONAL PRESBYOPIA ABSOLUTE PRESBYOPIA PREMATURE PRESBYOPIA NOCTURNAL PRESBYOPIA
  19. 19. • (1) incipient presbyopia  The beginning of presbyopia  (2)functional presbyopia  When it disturbs the visual function  (3)absolute presbyopia  When no accommodation ability remains
  20. 20. • (4) premature presbyopia At an early age • (5) nocturnal presbyopia Decrease amplitude of accommodation in dim light.
  21. 21. SYMPTOM DIFFICULTY IN NEAR VISION ASTHENOPIC SYMPTOM INTERMITTENT DIPLOPIA TREATMENT OPTICAL SURGICAL
  22. 22. PATHOLOGICAL ACCOMMODATION INSUFFICIENCY OF ACCOMMODATION ILL – SUSTAINED ACCOMMODATION INERTIA OF ACCOMMODATION PARALYSIS OF ACCOMMODATION
  23. 23. INSUFFICIENCY OF ACCOMMODATION • It is used when the accommodative power is significantly less than the normal physiologic limits for the patient’s age. • Can result from systemic conditions such as diabetes mellitus, multiple sclerosis, anemia, general physical fatigue, trauma.
  24. 24. CLINICAL FEATURES • Headache & fatigue • Blurred vision for near • Irritability of the eye • Accommodative failure & convergence insufficiency which may cause intermitted diplopia
  25. 25. TREATMENT o Treatment of the cause o Near vision spectacle o Accommodation exercise
  26. 26. ILL SUSTAINED ACCOMMODATION • It is a condition of accommodation fatigue refers to a situation in which although the range of accommodation is normal but cannot be sustained for a sufficient time period.
  27. 27.  CAUSES: • Asthenopic symptoms • Ill health • Uncorrected refractive error • Over work & emotional stress  TREATMENT • Correction of refractive error • Push-up test • Distance & near chart exercise
  28. 28. ACCOMMODATION INERTIA • It is a condition in which there is difficulty in adjusting the accommodation according to the distance of the object of regard so as to gain clear vision.
  29. 29. TREATMENT • Correct any refractive error. • Practise of any accommodation exercise.
  30. 30. PARALYSIS OF ACCOMMODATION • Paralysis of accommodation also known as cycloplegia refers to complete absence of accommodation.
  31. 31. TREATMENT • Self recovery occurs in drug induced paralysis and in diphtheric cases { once the systemic disease is treated} • Dark glasses are effecting in reducing glare • Convex lenses for near vision may be prescribed if the paralysis is permanent.
  32. 32. INCREASED ACCOMMODATION EXCESSIVE ACCOMMODATION SPASM OF ACCOMMODATION
  33. 33. EXCESSIVE ACCOMMODATION • The term excessive accommodation is used to describe a situation in which an individual exerts more than normal accommodation for performing certain near work.
  34. 34. CAUSES  young hypermetropes Young myopes Astigmatic error Presbyopes Use of improper spectacle
  35. 35. CLINICAL FEATURES • Varying degree of blurred vision due to induced pseudo myopia • Asthenopic symptoms • Both the far point and near point are brought nearer to the eye
  36. 36. TREATMENT Optical treatment General treatment
  37. 37. SPASM OF ACCOMMODATION • It refers to exertion of abnormally excessive accommodation which is out of the voluntary control of the individual.
  38. 38. CLINICAL FEATURES • Varying blurred vision due to induced pseudomyopia • Asthenopic symptom • Headache and browache are typical feature • Near point is abnormally close
  39. 39. TREATMENT Relaxation of ciliary muscle optical general

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