2. Accommodation
Unit of measurement
Accommodative insufficiency
Signs & symptoms
Care process
Management
Conclusion
References
3. 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.
4. 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)
5. 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
6. Time from birth Amp Acco
Birth 18.5D
8 years 14D
40 years 4D
70 years 0.0D
We lose 1D every 4 years
9. 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
10. 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?”
11. Some children with
accommodative insufficiency do
not present complaint? Why
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
for near
Headaches
Eyestrains
Reading
problems
Fatigue &
sleepiness
Loss of
comprehensio
n over time
21. 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
22.
23. 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.
24. 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.
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 be eradicated ( medical
problems, drugs, ophthalmic etc…) if present
27. 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
28. Prescribing reading glasses
decrease the demand on
accommodative system. However,
accommodation becomes passive
(it is problem we are
discussing)
29. 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
30. 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
31. 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
33. 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.
34. 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.
35. 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.
37. 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
38. 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
39. 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.
Notas del editor
often have accommodative dysfunction, because accommodation compensates for hyperopia
should be advised for patient with excess accommodative response
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.