GauriSh Shrestha,
M.Optom, FIACLE
Program Co-ordinator
Institute of Medicine
Sadhana Sharma, B.Optom II year
 Accommodation
 Unit of measurement
 Accommodative insufficiency
 Signs & symptoms
 Care process
 Management
 Conclusion
 References
 It is the dioptric adjustment of the crystalline
lens of the eye to obtain clear vision for a
given target of regard.
 It is the process by which the refractive
power of eye is altered to ensure a clear
retinal image.
 Ciliary muscle contracts (ciliary ring
shortens & zonules are relaxed)
 Tension in capsule is relieved (equator
of lens move forward & lens becomes
spherical)
 Dioptric power of lens increases (near
object focuses clearly on retina)
 The lens fibers & lens capsule lose their elasticity
 Size & shape of the lens increases
 Decrease accommodative amplitude
 The difference between the dioptric power need to
focus for near(P) and distance (R) is called
amplitude of accommodationamplitude of accommodation
 A= P-RA= P-R
Time from birth Amp Acco
Birth 18.5D
8 years 14D
40 years 4D
70 years 0.0D
We lose 1D every 4 years
10
15
20
25
30
35
40
45
50
55
14 12 10 8.5 7 5.5 4.5 3.5 2.5 1.75
0
10
20
30
40
50
60
1 2 3 4 5 6 7 8 9 10
Age(yrs) Amp(D)
 Max= 25-0.4 (Age)
 Average= 18.5- 0.3 (age)
 Min= 15.5-0.25 (Age)
 Accommodative insufficiency is an anomaly
that is characterized by an inability to focus
or sustain focus at near
 An insufficient amplitude of accommodation
based on age-expected norms
 Headache: “Do you get a headache when you read
or study?”
 Asthenopia: “Do you feel tiredness or tearing in
the eyes when you read or study?”
 Floating text: “Do you see the words appear to
float on the page, swim, jump or wiggle when you
read or study?”
 Facility problems: “Do you have difficulties in
quickly changing focus from the board, to your
textbook, and back to the board again?”
 Some children with
accommodative insufficiency do
not present complaint? Why
 Relationship between AC/A ratio
 Relationship between CA/C
1. Ophthalmic :
 Disease of accommodating components
 Hypermetropia
 Uncorrected myopia (noticed by the patient after
correction of refractive error)
2. Medical :
 Poor general health, malnutrition, general
weakness
3. Trauma :
 Trauma to eye resulting in loss of
acommodation
4. Drugs :
 Certain drugs adversely affect
accommodation such as antidepressants,
cycloplegics, antihistamines, Marijuana
etc
 Blurred vision
for near
 Headaches
 Eyestrains
 Reading
problems
 Fatigue &
sleepiness
 Loss of
comprehensio
n over time
 Pulling sensation
around eye
 Movement of print
Visual acuity
Variability between
near & distance VA
may indicate
accommodative
anomaly.
Refraction
- uncorrected hyperopia (Latent
hyperopia)
 Esotropia
Reduced convergence demand
causing accommodative dysfunction
 Exotropia
Vergence dysfunction causing
accommodative dysfunction
 CI notices
clear vision
 AI notices blur
vision
 RAF rule Method (Push up method)
moving a test object closer to eyes
 Positive relative accommodation
(PRA) Method
placing a minus lens in front of eyes
 Lag of Accommodation
Dynamic retinoscopy
 Near point card is placed at a distance
of 40 cm.
 Patient is instructed to watch 20/20 line
of letter each eye separately
 Asked to report when letter begins to
blur as minus power is gradually added
to patient’s subjective correction.
 To arrive at amplitude of accommodation, Add
2.50 D (for 40 cm WD) to minus lens power used
to blur the letters.
 For e.g. if add of -4.00D to subjective refraction
blurs the letters, the amplitude of accommodation
is
+4.00 + 2.50 D = 6.50D
 If positive lenses is necessary to add to clear up
the letter at 40 cm, the amount of plus power
necessary to clear up the letter is subtracted from
2.50D to determine amplitude of accommodation.
Basis for treatment
- General Principles are :
 To assist the patient to function efficiently
in near vision tasks
 To relieve ocular, physical & psychological
symptoms associated with disorders.
Cause should be eradicated ( medical
problems, drugs, ophthalmic etc…) if present
Optical correction
Appropriate refractive correction
first
Estimate amount of amplitude of
accommodation for given age if it is
disabling for near visual task,
Prescribe glass to relieve symptoms
 Prescribing reading glasses
decrease the demand on
accommodative system. However,
accommodation becomes passive
(it is problem we are
discussing)
 Solution:
Amp of Accommodation =6.0D
Functional amplitude of
accommodation=3.0D
Max near working distance = 33.3cm
Normal Amp of accommodation for
the age= 13D
Deficit is 7 D for the age= not
practicable to prescribe
Maintain least distance of distinct
vision= 25cm= 4.0D
Glasses should be prescribed at least
1.0D
Range of accommodation for near
work= 25cm to 50cm
 The purpose of accommodative therapy
is to increase the amplitude, speed,
accuracy & ease of accommodative
response.
 At the end of therapy patient should be
able to make the rapid accommodative
responses without evidence of fatigue.
 A vision therapy for accommodative
insufficiency usually requires 12 to 24
office visits
In office
1.Flippers
2.Brock-string
exercise
3.Hart-chart rock
exercise
4.minus lens
procedure
In home
1. Push up paddle
2. Hart chart rock
exercise
3. Flippers
4. Brock-string
exercises
 It is a holder with two minus & two
plus lenses of equal magnitude
 Subject focuses through one pair of
lenses at an object at near distance
(40 cm)
 When object is clearly focused, a
flick is quickly performed to the
other lens pair & subject focuses
through this.
 Process is then again repeated.
 Through changing the fixation distance it is
done with large & small hart charts,
consisting of ten rows, each with ten letters
 Letters of large chart have a visual subtense
of 20/20 at a distance of 20 feet.
 Small chart is a small version of large hart
chart
 Children using these charts practice keeping
their places when switching from far to near.
 Consists of a white string
of approximately 10 feet
in length with 3-5 small
wooden beads of
different colors.
 During therapy one end
of string is held at tip of
nose whereas the other
end is tied to a fixed
point.
Explain the procedure
 Monocular versus binocular
 Person reads a letter in a push
up paddle while moving the
target closer until sustained blur
is noticed
 Can be combined with distance
Hart chart rock
 Principle similar to flipper lens.
 Minus lens of increased strength is
gradually introduced in front of each eye
while the subject reads 20/20 equivalent
letters at near until s/he notices blur. S/he
must be encouraged to make letters read
clear
 Treatment is best addressed by use of
therapeutic spectacle lenses. The usually
prescribed ones are multifocal form to
allow improved near vision while not
disturbing distance vision.
Accomodative insufficiency s

Accomodative insufficiency s

  • 1.
    GauriSh Shrestha, M.Optom, FIACLE ProgramCo-ordinator Institute of Medicine Sadhana Sharma, B.Optom II year
  • 2.
     Accommodation  Unitof measurement  Accommodative insufficiency  Signs & symptoms  Care process  Management  Conclusion  References
  • 3.
     It isthe dioptric adjustment of the crystalline lens of the eye to obtain clear vision for a given target of regard.  It is the process by which the refractive power of eye is altered to ensure a clear retinal image.
  • 4.
     Ciliary musclecontracts (ciliary ring shortens & zonules are relaxed)  Tension in capsule is relieved (equator of lens move forward & lens becomes spherical)  Dioptric power of lens increases (near object focuses clearly on retina)
  • 5.
     The lensfibers & lens capsule lose their elasticity  Size & shape of the lens increases  Decrease accommodative amplitude  The difference between the dioptric power need to focus for near(P) and distance (R) is called amplitude of accommodationamplitude of accommodation  A= P-RA= P-R
  • 6.
    Time from birthAmp Acco Birth 18.5D 8 years 14D 40 years 4D 70 years 0.0D We lose 1D every 4 years
  • 7.
    10 15 20 25 30 35 40 45 50 55 14 12 108.5 7 5.5 4.5 3.5 2.5 1.75 0 10 20 30 40 50 60 1 2 3 4 5 6 7 8 9 10 Age(yrs) Amp(D)
  • 8.
     Max= 25-0.4(Age)  Average= 18.5- 0.3 (age)  Min= 15.5-0.25 (Age)
  • 9.
     Accommodative insufficiencyis an anomaly that is characterized by an inability to focus or sustain focus at near  An insufficient amplitude of accommodation based on age-expected norms
  • 10.
     Headache: “Doyou get a headache when you read or study?”  Asthenopia: “Do you feel tiredness or tearing in the eyes when you read or study?”  Floating text: “Do you see the words appear to float on the page, swim, jump or wiggle when you read or study?”  Facility problems: “Do you have difficulties in quickly changing focus from the board, to your textbook, and back to the board again?”
  • 11.
     Some childrenwith accommodative insufficiency do not present complaint? Why
  • 12.
     Relationship betweenAC/A ratio  Relationship between CA/C
  • 13.
    1. Ophthalmic : Disease of accommodating components  Hypermetropia  Uncorrected myopia (noticed by the patient after correction of refractive error) 2. Medical :  Poor general health, malnutrition, general weakness
  • 14.
    3. Trauma : Trauma to eye resulting in loss of acommodation 4. Drugs :  Certain drugs adversely affect accommodation such as antidepressants, cycloplegics, antihistamines, Marijuana etc
  • 15.
     Blurred vision fornear  Headaches  Eyestrains  Reading problems  Fatigue & sleepiness  Loss of comprehensio n over time
  • 16.
     Pulling sensation aroundeye  Movement of print
  • 17.
    Visual acuity Variability between near& distance VA may indicate accommodative anomaly.
  • 18.
  • 19.
     Esotropia Reduced convergencedemand causing accommodative dysfunction  Exotropia Vergence dysfunction causing accommodative dysfunction
  • 20.
     CI notices clearvision  AI notices blur vision
  • 21.
     RAF ruleMethod (Push up method) moving a test object closer to eyes  Positive relative accommodation (PRA) Method placing a minus lens in front of eyes  Lag of Accommodation Dynamic retinoscopy
  • 23.
     Near pointcard is placed at a distance of 40 cm.  Patient is instructed to watch 20/20 line of letter each eye separately  Asked to report when letter begins to blur as minus power is gradually added to patient’s subjective correction.
  • 24.
     To arriveat amplitude of accommodation, Add 2.50 D (for 40 cm WD) to minus lens power used to blur the letters.  For e.g. if add of -4.00D to subjective refraction blurs the letters, the amplitude of accommodation is +4.00 + 2.50 D = 6.50D  If positive lenses is necessary to add to clear up the letter at 40 cm, the amount of plus power necessary to clear up the letter is subtracted from 2.50D to determine amplitude of accommodation.
  • 25.
    Basis for treatment -General Principles are :  To assist the patient to function efficiently in near vision tasks  To relieve ocular, physical & psychological symptoms associated with disorders.
  • 26.
    Cause should beeradicated ( medical problems, drugs, ophthalmic etc…) if present
  • 27.
    Optical correction Appropriate refractivecorrection first Estimate amount of amplitude of accommodation for given age if it is disabling for near visual task, Prescribe glass to relieve symptoms
  • 28.
     Prescribing readingglasses decrease the demand on accommodative system. However, accommodation becomes passive (it is problem we are discussing)
  • 29.
     Solution: Amp ofAccommodation =6.0D Functional amplitude of accommodation=3.0D Max near working distance = 33.3cm Normal Amp of accommodation for the age= 13D
  • 30.
    Deficit is 7D for the age= not practicable to prescribe Maintain least distance of distinct vision= 25cm= 4.0D Glasses should be prescribed at least 1.0D Range of accommodation for near work= 25cm to 50cm
  • 31.
     The purposeof accommodative therapy is to increase the amplitude, speed, accuracy & ease of accommodative response.  At the end of therapy patient should be able to make the rapid accommodative responses without evidence of fatigue.  A vision therapy for accommodative insufficiency usually requires 12 to 24 office visits
  • 32.
    In office 1.Flippers 2.Brock-string exercise 3.Hart-chart rock exercise 4.minuslens procedure In home 1. Push up paddle 2. Hart chart rock exercise 3. Flippers 4. Brock-string exercises
  • 33.
     It isa holder with two minus & two plus lenses of equal magnitude  Subject focuses through one pair of lenses at an object at near distance (40 cm)  When object is clearly focused, a flick is quickly performed to the other lens pair & subject focuses through this.  Process is then again repeated.
  • 34.
     Through changingthe fixation distance it is done with large & small hart charts, consisting of ten rows, each with ten letters  Letters of large chart have a visual subtense of 20/20 at a distance of 20 feet.  Small chart is a small version of large hart chart  Children using these charts practice keeping their places when switching from far to near.
  • 35.
     Consists ofa white string of approximately 10 feet in length with 3-5 small wooden beads of different colors.  During therapy one end of string is held at tip of nose whereas the other end is tied to a fixed point.
  • 36.
  • 37.
     Monocular versusbinocular  Person reads a letter in a push up paddle while moving the target closer until sustained blur is noticed  Can be combined with distance Hart chart rock
  • 38.
     Principle similarto flipper lens.  Minus lens of increased strength is gradually introduced in front of each eye while the subject reads 20/20 equivalent letters at near until s/he notices blur. S/he must be encouraged to make letters read clear
  • 39.
     Treatment isbest addressed by use of therapeutic spectacle lenses. The usually prescribed ones are multifocal form to allow improved near vision while not disturbing distance vision.

Editor's Notes

  • #19 often have accommodative dysfunction, because accommodation compensates for hyperopia should be advised for patient with excess accommodative response
  • #22 Push – up method With the best visual acuity subjective lens ,reduced snellen chart is placed at a distance of 40 cm& patient’s attention is drawn to 20/20 row of letters. For monocular determination of NPA ,the left eye is occluded & patient keeps focus onthe 20/20 row of letters on the reduced snellen chart as the chart is moved closer. Patient is asked to report the blur point .At this point NPA is recorded as distance in (cm) from test card to spectacle plane of eye as indicated on reading rod.