revisi jurnal reading +crit app

7/27/2019 REVISI Jurnal Reading +Crit App

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Represented by :

Satya Hutama Pragnanda


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Glaucoma is amajor cause of

visual dysfunction

IOP is the riskfactor

progressive

structural &functional

damage to theoptic nerves


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Changes in body position can have

significant effects on IOP, with

elevations occurring in the supine and

head-down positions

The possible impact of theseelevations on glaucoma pathogenesisindicates a need to clearly understand

the effects of body position on IOP


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The magnitude of the

changes owing to body

position -> uncertain

differences between sitting

and supine IOP ranging from

0,3-5,6 mmHg

Previous studies

evaluating IOPand body position

have typically

utilized a fixed

measurement

sequence


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No previous studies have

investigated the effects ofbody position in a

randomized fashion to

eliminate the effects of

measurement sequence

In addition, the effect of

head position on IOP inhuman subjects is poorly

understood


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May beimportant

for:

Understanding

glaucomapathogenesis

Providing clinicalrecommendations

for glaucomapatients


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To investigate the effect of differenthead and body positions on intraocular

pressure (IOP) in a randomized study

Objective:


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IOPmeasurement*

Sitting

NeutralNeck

ExtensionNeck

FlexionNeck

Recumbent

SupineLeft

LateralDecubitus

RightLateral

Decubitus

* with the order of these sets of measurements randomized.All IOP measurements were performed with pneumatonometry.


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Prospective,comparative case

series

Design:

Twenty-fourhealthy volunteers

Participants:


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Healthy volunteers, male and female,

with refractive error between -4.00

and +2.00 diopters,were recruited

from students and employees ofMayo Clinic, and local area residents

Subjects were given a

complete dilated eye

examination


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systemic use of - blockers or steroids

Diabetes

Sitting IOP > 22 mmHg Any evidence of ocular pathology including

history of trauma or surgery, glaucoma,narrow angles, strabismus, infection, corneal

scarring, uveitis, or retinal tear ordetachment.

Subjects who could not tolerate neck flexion

or extension for 5 minutes duration

Exclusion criteria :


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Minimum 5 minwas allowed in eachposition before IOP

measurement STEADY STATE

Topicalanesthesia with

propacaine 0,5%

in both eyes

IOP wasmeasured usingpneumatometer

Averaged foreach eye from

three

measurements

Measurementsthat were > 3

mmHg than themean IOP were

rechecked


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Assuming sitting IOP to be 13.8+2.3 mmHg, the

necessary sample size was calculated to be 24 (

=0.05 and =0.2)

IOP measurements for right and left eyes in each

position were compared using paired t-tests

Statistical significance was assumed for P


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24

subjects*

Age

19 to

47years

7 men and 17 women

mean age of28.6+8.5 years

*All subjects were Caucasian (reflecting the ethnic makeup of the Olmsted County,

Minnesota, area) and low myopes, with a mean refractive error of -2.6+0.77 diopters(mean + standard deviation, spherical equivalent).


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Position

Intraocular Pressure (mmHg)

Right Left Bilateral

Sitting

Neck neutral

Neck extension

Neck flexion

15.0 2.1

16.5 2.6

20.2 4.1

14.6 2.0

16.3 2.8

19.4 3.7

14.8 2.0

16.4 2.7

19.8 3.8

Recumbent

Supine

RLD

LLD

17.3 3.1

18.8 2.9

17.6

2.6

17.3 2.9

17.7 3.1

18.3

2.8

17.3 2.9

18.3 3.0

17.9

2.7


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PositionPValues

Right VersusLeft

Sitting Neutral Supine

Sitting

Neck neutral

Neck extension

Neck flexion

0.24

0.45

0.15

-

< 0.0001

< 0.0001

-

0.010

< 0.0001

Recumbent

Supine

RLD

LLD

1.00

0.016

0.076

< 0.0001

< 0.0001

< 0.0001

-

0.006

0.058


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Previous studies : IOP is typically higher in

the supine position than the sitting position

The amount of increase in IOP from sitting to

supine position is greater in open-angle

glaucoma, ocular hypertension, or normaltension glaucoma compared with normal

subjects


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Most of studies performed measurements

in fixed sequence confounding factor,because the measurement sequence

affected the magnitude of the IOP change

that occurs with body position


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Other factors that may affect the IOP

change with body position are incompletely

understood

Axial length postural IOP change


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Mechanism for IOP change body position incompletely understood

Previous study

>>> EVP in recumbent position

choroidal vascular engorgement redistribution

of body fluid


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No previous study has reported the effect ofneck flexion on IOP

Klein,et.al.

>> IOP during neckhyperextention This study a significant >> neck extention

even greater >> on neck flexionhydrostatic pressure & increase of EVP


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Hwang et al alteration in IOP afterpositional change supine Lateral decubitus

2 mmHg >> IOP from supine tolat.decubitus 4 mmHg 30 minutes

This study1 mmHg after 5 on dependenteye hydrostatic effect & increase in EVP


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The observed increase in the dependent eye

may be due to the hydrostatic effects & >>

EVP

Differences in the magnitude of IOP elevation

in the dependent eye in the RLD compared

with LLD maybe caused by rightleft

differences in the cardiovascular system


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Only young, healthy subjects were included

Numerous factors -> positional changes in IOP ->

agingCircardian rhythms -> IOP changes -> unknown ->

aqueous humor dynamics variations

Further research -> to investigate the

positional changes in IOP in older subjects

and glaucoma patients


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In normal subjects, IOP is lowest whenmeasured while sitting with the neck in the

neutral position

Other head and body positions result IOP>> compared with the position used fortypical clinical measurements

RLD - LLD positions may result in a smallincrease in the IOP in the lower eye

Further research : determine whethersimilar elevations of IOP occur in glaucoma

patients


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PATIENT:24 healthy volunteers, male and female,

with refractive error between -4.00 and +2.00 diopters INTERVENTION:

IOP measurement in each sample with six differentpositions using pneumatometer

COMPARE:Comparing the IOP between sitting and recumbentposition

OUTCOME:Mean IOP is lowest when measured while sitting withthe neck in the neutral position


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TITLE

Too long / short ? Not more than 12 words, can illustratethe journal content generally

Illustrate the observedvariables ?

Yes

Non standard Abbreviation? None

Any corresponding author

and email ?

Obviously,Author : Mehrdad Malihi, MD ;

Corresponding Author : Arthur J.Sit,

SM,MD

E-mail : [email protected]


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ABSTRACT

Consists of 4 parts:

background, method, result,and conclusion ?

Yes, 4 parts: background, method,

result, and conclusion

Any keywords ? None

Do the abstract is wholly

appropriate ?Yes

AIM & BENEFIT OF THE RESEARCH

Does the aim explained ? Yes

oes the benefit explained ? Yes


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METHODS

Is there any research design ? Yes, it is explained

Population & samples Yes, it is explained

Inclusion-Exclusion Criteria Yes, it is explained

Sampling & Sample size

formulation

Yes, it is explained

Did the subject selection is

appropriate?

Is there any bias ?

Incorrect, because only young and

healthy subject involved

Treatment Yes, it is explained


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METHODS

Did the measurement blind ? NO

Is there any bias on

procedure, means, and

subject obedience ?

NO

Is there any explanation

about independent &

dependent variables ?

Yes, it is explained

Is there any operational

definition ?YES

Is there any ethical clearance

consent ?

Yes, by Institutional Review Board of

Mayo Clinic according to Declaration

of Helsinki (1989)

Data anal sis ? Yes usin aired t-tests

RESULTS


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RESULTS

Any Drop out ? None

Is there any subjectcharacteristic table ?

None

Is there any aim for the

results?Obviously

What is the main result of

the research ?

Averaged IOP in sitting with neutralneck position


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CONCLUSION

Could it be applied in

chosen sample, reachable

and target population ?

Yes, but it needs further research

Could this research be

applied for patients ?Applicable


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Source :


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Source :Liu JHK,et.al., Twenty-fourHour I ntraocular Pressure Pattern Associatedwith Ear ly Glaucomatous Changes, Investigative Ophthalmology & VisualScience. April 2003, Vol. 44, No. 4

Mean diurnal IOP (sitting/supine), glaucoma group>>>>> control group

Nocturnal supine IOP >>>> Diurnal sitting IOPDiurnal-to-nocturnal IOP increase


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IOP pattern from 5:30 7:30 AM

The two groups, the posture-independent IOPlevel changed in different : >>>> in the glaucomagroup,


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Body was tilted from standing to supine, HR > 29% (P 0.001)

The ocular perfusion pressure increases by purelyhydrostatic considerations

Longo, Antonio ,et.al., Posture Changes and Subfoveal Choroidal Blood Flow ,Investigative Ophthalmology & Visual Science. February 2004, Vol. 45, No. 2

Source :


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Source :

Longo, Antonio ,et.al., Posture Changes and Subfoveal Choroidal Blood Flow,

Investigative Ophthalmology & Visual Science. February 2004, Vol. 45, No. 2

Group Averaged Brachial Artery BP, IOP, and HR atthe Different Postures

PosturesBP Syst

(mmHg)

BP Diast

(mmHg)

BP mean

(mmHg)

IOP

(mmHg)

HR

(b/min)

Baseline 116 1581 7 96 10 13 1 82 13

Supine124 13 75 6 95 8 17 2 69 10

Recovery117 15 81 6 96 9 - 80 11


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Hydrostatic pressure occurs in the vascular system

because of the weight of the blood in the vessels.

The positional hydrostatic factor = p x g / 1360 x hmmHg

p : blood density (1.05 g/cm3)

g : acceleration due to gravity (980 cm/sec2)h : height from the reference point (cm)(- n ) for above the reference


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IOP >> from sitting to supine4,4 mmHg Control Group4,0 mmHg Ocular Hypertension

4,1 mmHg Low Tension Glaucoma

Pressure increase in Episcleral vein

Indicate that some glaucoma patient exhibit faultyregulation of central artery blood flow duringposture change


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Significant reduction in IOP, measured with CT80post Goldmann tonometer, 1 mmHg

Due to a decreased anterior chamber volume due toincreased aqueous outflow


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As eyes move from above heart level (sitting/standing position) to heart level (supine position)or even below heart level (inverted position), the

episcleral venous pressure increase -> resistance

That must be overcome for aqueous passage

through the trabecular pathway, and so it is the keydeterminant of steady state IOP


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Utilizes a pneumatic sensor (consisting of apiston floating on an air bearing).

Filtered air is pumped into the piston and travels

through a small (5-mm diameter) membrane atone end. This membrance is placed against the cornea.

The balance between the flow of air from themachine and the resistance to flow from the

cornea affect the movement of the piston andthis movement is used to calculate the intra-ocular pressure.


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The pressure inside an ideal dry, thin walledsphere equals the force necessary to flatten its

surface divided by area of the flattening

P = F / A

P = PressureF = ForceA = Area


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IOP in the undisturbed eye :

P0 = (F/C) + Pv

P0 = Intra Ocular Pressure in mmHgF = rate of aqueous formation in L/min

Pv = Episcleral Venous Pressure (mmHg)C = 1/R R = resistance to outflow


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Friedenwald(1948) found the average normalcoefficient ofocularrigidity to be K = 0.0245

Pt 1 : tonometric pressure V 1 : volume of the indentation caused by the

bar in the determination made with the first

weight Pt 2,V 2 : values as obtained with the second

weight; K : coefficient of ocular rigidity

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