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JOURNAL CLUBACCOMMODATIVE INSUFFICIENCY…
Amrit Pokharel
Accommodation Insufficiency in Children: Are Exercises Better than Reading Glasses?
Strabismus 2008; 16:65–69. Copyright _c 2008 Informa Healthcare USA, Inc. ISSN: 0927-3972 print / 1744-5132 online DOI: 10.1080/09273970802039763
Researchers
Rune Brautaset,BSc (Optom), MPhil, PhD,Marika Wahlberg,BSc (Optom),Saber Abdi, BSc, MSc(Orthop), PhD,and Tony Pansell,BSc (Optom), PhDUnit of Optometry, Departmentof Clinical Neuroscience,Karolinska Institute, Stockholm,Sweden
Purpose:
The aim of the study was to compare efficacy of plus lens (+1.00D) reading addition (PLRA) with that of spherical flipper (±1.50D) in the treatment of accommodative insufficiency (AI).
INTRODUCTION
The normal accommodative system is often described as
Accommodative dysfunction is a relatively common visual anomaly in children and young adults.
flexible resistant to fatigue
INTRODUCTION
The prevalence of accommodative dysfunction
probably affects at least 2–3% of the population (Rutstein & Daum, 1998).
not associated with presbyopia
INTRODUCTION
Accommodative dysfunction :
Near Work
Accommodative
Insufficiency
INTRODUCTION
AI is a condition in which the amplitude of accommodation is
chronically the lower limit of the expected amplitude for the patient’s age
as measured with push-up accommodative stimuli
(Mein & Trimbel, 1994; Benjamin, 1998)
INTRODUCTION
AI subjects also demonstrate a reduced accommodation facility (Scheiman
&Wick, 1994)
Sometimes an lag of accommodation (Rutstein & Daum, 1998; Scheiman &Wick, 1994).
INTRODUCTION
AI has been reported to be the most common cause of asthenopia in schoolchildren between 8 and 15 years of age (Borsting et al., 2003).
INTRODUCTION
manifest a range of non-strabismic accommodative and vergence disorders (Abdi et al., 2006).
Vision Therapy
INTRODUCTION
Visual therapy involves purposeful and controlled manipulations of
target blur, disparity and proximity, with the aim of
normalizing the a c c o m m o da tive s y s te m , the ve rg e nc e s y s te m , a nd m utua l inte ra c tio ns (Griffin & Grisham, 1995; Rutstein & Daum, 1998).
INTRODUCTION
The two most important vision therapy regimes for AI are
(Daum, 1983b; Mazow et al., 1 989; Rutstein & Daum, 1998)
plus lens reading additions (PLRA)
INTRODUCTION
PLRA
Passive mode of therapy
Gives a helping hand in getting a clear retinal image
INTRODUCTION
PLRA
The amount of blur decreases when wearing glasses
Role reduce blur to such an extent that the remaining blur is recognized and within the subject’s accommodative capacity.
INTRODUCTION
The subject’s task is to recognise the remaining image blur and to clear the image. However, by being able to clear the image, the blur-driven sensors and the adaptive mechanism within the accommodative system will start to regain normal capacity (Ciuffreda, 2002).
INTRODUCTION
the initial amount of blur is not reduced
however, a controlled amount of additional blur (with the negative side of
the flipper)
a controlled amount of reduction in blur (with the
positive side of the flipper)
INTRODUCTION
The subject’s task is to recognise the change in defocus of the image and
to try to respond by obtaining a clear image.
By being able to recognise and respond to the blurred image, the blur-driven sensors and the adaptive
mechanism within the accommodative system will start to regain normal capacity (Ciuffreda, 2002).
Rationale
To clarify the issue of whether PLRA or orthoptic exercises are equally effective or whether one method is more effective than the other.
MATERIALS AND METHODS
Partly blind study Consisted of assessments by three
examiners.
E1 E2
E3
Inclusion criteria
MATERIALS AND METHODS
Inclusion Criteria: Symptoms revealing uncomfortable vision
and/or
refractive error less than 1 . 0 0 D o f hyp e rm e tro p ia and less than 0 . 5 0 D o f m y o p ia , and/or a s tig m a tis m le s s tha n 0 . 5 0 D m e a s ure d in c y c lo p le g ia
MATERIALS AND METHODS
Inclusion Criteria: distance heterophoria between 2 p d of exophoria
and 2 p d of esophoria
near (40 cm) heterophoria between 6 p d of exophoria and 4 p d of esophoria
near point of convergence of 10 cm or better on the RAF (Royal Air Force) rule
MATERIALS AND METHODS
Inclusion Criteria: fusional reserve at least twice the near phoria
near point of accommodation worse than (100/(15D-(0.4 age))) on the RAF rule
distance Snellen visual acuity of 0.8 or better both monocularly and binocularly
normal ocular motility
MATERIALS AND METHODS
Inclusion Criteria: full stereo vision on the Lang II test
no ocular pathology
no history of ophthalmologic treatment
not taking any drugs with a known effect on visual acuity and/or binocular function and accommodation.
MATERIALS AND METHODS
E1 asked the subjects to consecutively participate in the study.
10 subjects-8 weeks of PRLA treatment
Age : 10.3 years ±2.74
24
10
24 subjects with AI(age: 10.3 ±2.5 )
9 subjects-8 weeks of Flipper treatment
5 drop outs Age: 10.3 years ±2.41
14
MATERIALS AND METHODS
If the subject met the inclusion criteria, the subject was seen by a second examiner (E2) who, without knowing the results of the inclusion examination, performed measurements of the study variables.
E2
MATERIALS AND METHODS
Study variables:
Accommodative amplitude Accommodative facility Lag of accommodation Visual Analogue Scale (VAS) score
E2
MATERIALS AND METHODS
were those assessed? AA- three measurements were taken
AF- accommodative facility at 40 cm with a ±2.00D flipper while fixating a vertical row of letters equivalent to 6/9 visual acuity (measured binocularly and in the dominant eye; dominance was tested with the Miles test (Michaels, 1975))
MATERIALS AND METHODS
were those assessed? lead/lag of accommodation as measured with
No tt d yna m ic re tino s c o p y while fixating a vertical row of letters equivalent to 6/9 visual acuity at 40 cm
subjective grading of the degree of asthenopia on a Visual Analogue Scale (VAS)
A visual analogue scale (VAS) is a psychometric response scale which can be used in questionnaires. It is a measurement instrument for subjective characteristics or attitudes that cannot be directly measured.
Numbering from 0-10.
MATERIALS AND METHODS
MATERIALS AND METHODS
If 0 equals no problem when doing near work and 10 equals the worst degree of problems, what number would you grade your problems at near work to be now?”
These four measures were repeated after the 8 weeks’ treatment period.
MATERIALS AND METHODS
The subject was then seen by a third examiner (E3) who, according to a randomization list and without knowing the results obtained by E1 and E2, assigned the subjects to either flipper or PLRA treatment.
E3
MATERIALS AND METHODS
E3 assigned glasses randomly
E3 assigned flipper treatment randomly
Mixed samples who met inclusion
criteria
E2 performed follow up examination at 8 weeks
E1 examination Included in study
E2 performed examination
MATERIALS AND METHODS
10 subjects-8 weeks of PRLA treatment
Age : 10.3 years ±2.74
24
10
24 subjects with AI(age: 10.3 ±2.5 )
9 subjects-8 weeks of Flipper treatment
5 drop outs Age: 10.3 years ±2.41
14
E3
MATERIALS AND METHODS
After 8 wks, re-examination by E2
without knowing the kind of treatment.
±1.50D flipper lenses Two sessions of nine
minutes each day To be done when not
tired or not feeling asthenopia
Done at 40 cm Done as many flips a
minute.
+1.00 lenses
Flipper PLRA
followed by another one-minute trial of flipping and a one-minute break.
repeated until the subject had done a total of five minutes of flipping
Target
use the glasses as much as possible for all types of near visual work.
Flipper PLRA
Statistical Methods
The effect of treatment (before vs. after),
the type of therapy regime (flipper vs. PLRA) and
the interaction effect between them were analysed using multivariate analysis of variance.
Statistical Methods
Bonferroni post-hoc analysis Planned comparison. Wilcoxon matched pair test was used for
analysis of the VAS score and the within-group results
A significance level of 0.05 was considered significant.
Dropouts have not been included in the analysis.
RESULTS
Accommodative Amplitude and Accommodative Facility Significant interaction between the study
variables and the treatment [F(2,34) = 6.97, p = 0.003].
The post hoc analysis showed a significant change in accommodative amplitude [F(1,17) = 18.84, p < 0.001].
RESULTS
Accommodative amplitude change over a period.
RESULTS
Accommodative facility change over a period.
RESULTS
Flipper vs. PLRA The analysis did not reveal any statistically
significant difference between the two therapy regimes [F(1,17) = 0.31, p = 0.58].
With the accommodative response excluded, the difference was still not significant [F(1,17) = 2.06, p = 0.17].
RESULTS
VAS
Flipper6.3 units lower after treatment
[Z(n = 9) = 2.66; p = 0.008]
PLRA4.7 units lower after treatment
[Z(n = 10) = 2.80; p = 0.005]
DISCUSSION
Visual therapy in AI involves Purposeful and
controlled manipulations of
target blur, disparity and proximity with the aim of normalizing the accommodative system (Griffin & Grisham, 1995; Rutstein & Daum, 1998).
DISCUSSION
The two most commonly used regimes of therapy for AI are fundamentally different.
PLRA is a much more passive type of treatment as compared with flipper treatment.
However, in both regimes, the aim is to improve the response of the blur-driven
sensors and the adaptive mechanisms within the accommodative system so that they can regain normal capacity (Ciuffreda, 2002).
DISCUSSION
The purpose of the present study was to evaluate which mode of therapy
is a more
PLRA FLIPPER
DISCUSSION
Expected values for accommodative amplitude in the age range tested in this study are between 14.0 and 16.5D (Rutstein & Daum, 1998).
This is less than the improvement found by Abdi et al. (2007) over a 12-week treatment period with the same +1.00D reading addition and less than that found by Daum (1983b).
DISCUSSION
The results of the present study show that
both methods improve accommodative amplitude. The improvement with PLRA was from 3.58D to 4.25D.
DISCUSSION
With
accommodative amplitude improved from 5.16D to 7.82D, a significant improvement
which occurred due to good compliance.Daum (1983)
DISCUSSION
Present study results Sterner et al. (2001).
The amount of treatment and the treatment time were comparable to the treatment regime used in this study.
DISCUSSION
The expected binocular values for accommodative facility are between 6 and 10 cpm (Rutstein & Daum, 1998).Before
treatment, all subjects performed worse on accommodative facility.
After treatment, all subjects reached values just within the normal range, irrespective of the treatment regime. Despite this, the improvement was small and not statistically significant (p = 0.06).
DISCUSSION
Before treatment, all subjects included had a grading of much more than 2 (7.3 and 8.1 on average in the PLRA and flipper groups, respectively).
VAS
DISCUSSION
The reduction in VAS score was significant in both groups, but only in the flipper group was an average VAS score below 2 achieved.
The higher level of improvement in accommodative amplitude and the lower VAS score after treatment in the flipper treatment group indicates that the treatment time needed will be shorter with
this type of treatment as compared with PLRA.
DISCUSSION
On the other hand, the fact that dropout only occurred in the flipper treatment group indicates that
it m a y be m o re d iffic ult to m o tiva te s ubje c ts to d o o rtho p tic e x e rc is e s a s c o m p a re d to we a ring re a d ing g la s s e s .
CONCLUSION
The results indicate that both methods improve the accommodative amplitude, but that overall accommodative function reaches higher levels of improvement with spherical flipper as compared with PLRA treatment.
However, the accommodative function did not gain normal values in 8 weeks of treatment with either regime.
Thank You