Brit. J. Ophthal. (I976) 6o, 687

Rapid pneumatic and Mackay-Marg applanation tonometryto evaluate the postural effect on intraocular pressure

M. R. JAIN AND V. J. MARMIONFrom Bristol Eye Hospital, Bristol

Glaucoma is usually considered to be adequatelycontrolled when Goldmann applanation readingsare below 22 mmHg. It is, however, now knownthat the intraocular pressure increases to a varyingdegree when the patient changes his posture fromsitting to a recumbent position (Galin, McIvor,and Magruder, I963; Roberts and Rogers, I964;Hetland-Eriksen, Ig66a; Inglima, I966; Tarkkanenand Leikola, I967; Langham and McCarthy, I968;Anderson and Grant, 1973). Hetland-Eriksen(I966a, b) stated that the increase in intraocularpressure when in a recumbent position is in someway directly proportional to the initial intraocularpressure; this complicates our dependence onGoldmann tonometry as that procedure is performedroutinely only in the sitting position.The present study, as well as making a clinical

evaluation of the Mackay-Marg tonometer and thepneumatonograph, assesses the relationship ofvarious postures to intraocular pressure in normaland glaucomatous eyes. The study was conductedusing two of the more modem rapid applanationtonometers: the pneumatonograph (PTG)* andthe Mackay-Marg electric tonometert as both areeasily portable and continuously monitor thepressure on graph paper, and in addition, they canbe used in any posture with equal ease and precision.Neither do they require the magnification orillumination of a slit-lamp nor the use of fluorescein,-as is essential in Goldmann tonometry. Thepneumatonograph (Jain and Marmion, I976) andthe Mackay-Marg (Kaufman, Wind, and Waltman,1970) can be used to record exact pressures incases of ectatic corneas or postkeratoplasty (Irvineand Kaufman, I969) as it is not imperative to applythe tip of the probe to the centre of the cornea ineither procedure.The correlation of the PTG (Jain and Marmion,

*Alcon Applanation Pneumatonograph TM, Alcon Universal Ltd,Fortworth, USA

-tBerkely Model 255 Mackay-Marg Electronic Tonometer withModel Probe 200

Address for reprints: V. J. Marmion, Consultant OphthalmicSurgeon, Bristol Eye Hospital, Bristol

I976) and the Mackay-Marg (Tierney and Rubin,I966) with the Goldmann has been shown to besignificant, although the mean pressures recordedby the PTG and the Mackay-Marg are reported tobe about i and 2 mm higher than those using theGoldmann.The main difference between the two instruments

is that the pneumatonograph is a combination of apneumatic and an electronic system, whereas theMackay-Marg is purely electronic and, whenapplanated, its recording system is driven by theslightest movement of the fuzed quartz plunger rod.The pneumatonograph has the advantage that theapplanation is confirmed by a continuous whistleand the pressure can be read instantaneously fromthe digital display as well as from recordings on thechart. Applanation is simpler with the Mackay-Margbut its accuracy cannot be confirmed and hence itis essential to make 4 to 5 applanations each timeto obtain a correct recording. The Mackay-Margtonometer requires calibration daily before use,whereas the PTG need be calibrated only once aweek. The Mackay-Marg is quicker in the sensethat single applanation requires only about a secondwhereas the PTG requires 2 to 5 seconds.

Precise study of amplitude of ocular pulse withthe PTG is a distinct advantage in the diagnosis ofcarotid occlusion, since the amplitude of ocularpulse is significantly affected even in cases with20 per cent carotid obstruction (Best and Rogers,1I974).

Material and methodsThe cases studied comprised three groups. Group Iconsisted of 20 normal young volunteers (40 eyes) withan age range of between IS and 29 years. The posturalstudy in this group was conducted only by the pneu-matonograph.Group 2 consisted of patients without glaucoma,

routinely attending the outpatient clinic and whocorresponded in age with the glaucomatous subjects.Patients included in this group were completely normal,cataractous, aphakics, or had defective vision or, insome cases, had some retinal disease such as diabeticretinitis, retinitis pigmentosa, etc.

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688 British Journal of Ophthalmology

Group 3 were all patients with open-angle glaucomaand were selected as follows:Those with previously undiagnosed glaucoma withintraocular pressures exceeding 22 mmHg.Those receiving treatment but with intraocularpressures exceeding 20 mmHg.Group 3 also included adequately controlled glau-

comatous patients who were advised to stop treatmentfor at least 24 hours before the study was conducted.Patients in this group were selected according to theirinitial sitting pressure readings using the pneumatono-graph. The number of patients included in Group 2was 76 (15I eyes) and in Group 3 54 (io8 eyes) with anage range of between 30 and 85 years.The pneumatonograph and the Mackay-Marg instru-

ments were connected to the mains, adjusted, andcalibrated as required. The Mackay-Marg tonometerused in this study required calibration to 9-5. The PTGsensor tip has to be sterilized in 70 per cent isopropylalcohol and a new autoclaved thin rubber tonocoverwas used for each new patient for the Mackay-Margprobe. The sequence of examination in this study wasas follows.The patient was comfortably seated erect on an

examination couch and the eyes were anaesthetized withdrops of 0o4 per cent benoxinate hydrochloride. Thepatient was asked to fix some object and avoid squeezingwvhile he held his gaze. The tip of the Mackay-Margprobe was applanated to the apical zone of the corneafor about half a second. Four to five applanations wererepeated in each eye. While applanating, care was takenthat the centre of the probe was the first thing to makecontact with the cornea and the withdrawal was abrupt.Soon after, with the patient in the same position, thetip of the PTG sensor probe was applanated to the apicalzone of the cornea for about two to five seconds. Acorrect applanation was confirmed by a continuouswhistle from the machine and the intraocular pressurewas displayed as well as being recorded on the chart.

Thereafter, the patient was asked to lie face upwardson the same couch and, after two minutes, the pressurewas recorded by both the Mackay-Marg and the PTG.The patient continued to lie in the same position andthe pressure was re-recorded after three minutes usingthe same instruments. Then a pillow with an effectivethickness of I2-7 cm was placed underneath the patient'shead and pressure was recorded after two minutes.Having done that, the patient was made to sit erect asoriginally and the pressure was recorded at two- and five-minute intervals. This way, with both tonometers, sixseparate pressure readings were obtained in variouspostures for each patient in Groups 2 and 3.To make the study more valid the following precau-

tions were taken:i. All measurements were performed by the same

examiner.2. The Mackay-Marg tonometer was calibrated daily

and the PTG once in seven days.3. All examinations were conducted on the same

examination couch and hence the patient was notrequired to walk even a single step.

4. Patients were requested to keep their eyes gentlyclosed during intervals to avoid any evaporationfrom anaesthetized cornea.

Results

AGE AND SEX DISTRIBUTION (Fig. i)

In Group i, the average age was 20o75 years andall the volunteers were women. In Groups 2 and 3,the ages ranged between 30 and 85 years with anaverage of 6i 72 years, but in most cases (8o077per cent) the ages ranged between 50 and 79 yearswith women predominating in almost all age groupsgiving an overall ratio of I3 : 9.

PNEUMATONOGRAPH READINGS COMPARED WITH

MACKAY-MARG

Fig. 2 is the complete scattergram for Groups 2 and3 (259 eyes). The Mackay-Marg readings areplotted on the ordinate and the pneumatonographon the abscissa. The correlation coefficient (R) is

FIG. I Ages and sexes in Groups I, 2, and 3 (I50 cases)

ao

ci

0 h=259r=0.91a= 1 13b=095Sb=0 02

0 10 20 30 40 50 60Pneumotonogroph

FIG. 2 Scattergram showing pneumatonograph andMackay-Marg intraocular pressure readings for 259 eyes(Groups 2 and 3) in initial sitting posture

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Rapid pneumatic and Mackay-Marg applanation tonometry 689

Meon introoculor pressure-P 0 )

- a-l

x

a b a bSitting Supine Pillow Sitting

a: after 2 min b: after 5 min

FIG. 3 Mean postural pressures in Group i volunteers(40 eyes) as recorded by pneumatonograph

O-9i. The calculated slope of the line is o095 (b)and the standard error of the slope is 002. Theintercept (a) is 1I13 and is interpreted to meanthat the average Mackay-Marg reading is abouti mmHg higher than the pneumatonograph reading.

POSTURAL CHANGE IN PRESSURE

Group i (Fig. 3). The mean initial intraocularpressure as recorded by the PTG was 15-65 ±0.25

0,-

0

WI

z

0.

.0

E3

30 to39yrs 40 to49yrs SOtoS9yrs 60 to69yrs 70+

Mackoy-Marg

Pneumatonograph

E|B rfl- M|mM M iF r F IIIII

Mackay-Ma:A

Pneumatonagraph

L , LU,REIMI> R

mmHg. There was an average increase in pressureof I4 mmHg within two minutes after lying supine(supine-a), then a slight decrease in supine (b) and'pillow' positions, but the decrease was significantwhen the patient was again sitting. The meanintraocular pressure recorded in the end (sitting-b)was o-82 mmHg lower compared with the initialsitting intraocular pressure.Groups 2 and 3. The results of the mean, standarderror of the mean, and standard deviations ofintraocular pressure recordings in various positionsusing the PTG and the Mackay-Marg tonometer forGroups 2 and 3, combined and separately, areshown in Fig. 4. The mean pressure recordings byMackay-Marg were uniformly higher by approxi-mately i mmHg in all positions. Fig. 4 and Table Ialso show that there was a statistically significantincrease in intraocular pressure when the patientchanged from sitting to lying. The range of rise inpressure in non-glaucomatous subjects was -2 to-8 mmHg and in glaucomatous eyes it rangedbetween o and IO mmHg. The mean rise in pressureusing the PTG was 2'71, 4-o4, and 3-28 mmHg inGroups 2, 3, and 2 plus 3, respectively. Using theMackay-Marg it was 2z5I, 3-72, and 2'79 mmHgin the same order. After this initial rise, there wasa slight fall in pressure in the supine posture and agreater fall when the pillow was placed under thehead, but the fall was significant (mean fall rangingbetween VI-5 and I-95 mmHg) compared with the

FIG. 4 Results of mean, standarderror of mean, and standarddeviations of pressure in Groups 2,3, and 2 plus 3 in various posturesas recorded by PTG and Mackay-Marg tonometer

-2 0 2 4 6 8 10 0 2 4 6 8100 2 4 6 84 06 10024681002 4 6 8 10-2 -2 -2 -2

Intraocular pressure (mm Hg)

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690 British Journal of Ophthalmology

Table I Mean and range of variation in intraocular pressure in different postures in group 2 and group 3separately and combined as recorded by pneumatonograph and Mackay-Marg tonometer

Pneumatonograph

I 2 3 4 5

Mean (mmHg) 2V71 o-26 0-44 0°30 I-15Range (mmHg) -2 to 8 -2 to 3 -I to 3 -2 to 3 0 to 3

Mackay-Marg tonometer

I 2 3 4 5

2-510I30 0-32 0-41 133-i to 8 -2 to 4 -1 to 4 -3 to 3 0 to 4

3 Mean (mmHg) 4-04 o 74 o-64 o-85 I-56 3y72 o096 o-86 o093 I-95(io8 eyes) Range (mmHg) o to IO -3 to 4 -2 to 3 -2 to 4 0 to 5 otoO -2 to 4 -2 to 4 -3 to 5 0 to 5

2 and 3 Mean (mmHg) 3-28 0-46 0o52 o057 I32 2-79 o055 o057 0o54 i-8i(259 eyes) Range (mmHg) -2 to Io -3 to 4 -2 to 3 -2 to 4 0 to 5 -I to IO -2 to 4 -2 to 4 -3 to 5 0 to 5

i =Supine (2 min) minus sitting (initial); 2= Supine (2 min) minus supine (5 min); 3 =Supine (5 min) minus pillow under head;4 =Sitting ( min) minus sitting (5 min); 5=Sitting (initial) minus sitting (5 min)

initial pressure when the patient was again sitting(Table I). The variation in pressure was greater inglaucomatous than in non-glaucomatous subjects.The classical clinical PTG pressure recordings invarious postures in two typical cases is shown inFigs 5 and 6.The results shown in Table II explore the

possibility of any relationship in age with thepostural rise in pressure. There were few patientsin the age groups 30 to 39 and 8o+ and if theyare excluded there would appear to be a directrelationship between postural rise in pressure and

(A) *45.

--RE 35

_. 1S

.(D)RE

^JFfV_

(B)

age in the age group 50 to 79 years in Group 2,as shown by recordings of both the PTG and theMackay-Marg (Table II). Fig. 7, which shows thefrequency distribution of postural pressure rise inGroups 2 and 3 at various ages confirms thisobservation. Comparative postural rise to a higherdegree is evident in older age groups, particularly inglaucomatous patients; I6-67 per cent in Group 2and 5-34 per cent eyes in Group 3 showed no

change in pressure as recorded by the PTG, and14 per cent of Group 2 even showed a fall in pres-sure of i to 2 mmHg by PTG. In none of the

45(C)

LE E. LE RE;.a^.zb r>,, i,/f^2ur!

2

> 25 -V

15

5.

*fE):LE

ArvRE

*4 (F)4s35 35

LE ,3 25RE

15 1

LE ..... tfetVVW

tSis t......

<e .-----._

LEf..I

FIG. 5 Shows clinical PTG pressure recordings of both eyes in various postures-(a) sitting, (b) supine 2 min, (c) supine5 min, (d) pillow under head, (e) sitting 2 min, (f) sitting 5 min

--N=.¢,== -: :0- :-: (B) -

-_RE LE..

-- I- *- -- 4- - - - - - ---___=-___=A. A, *,.A:

LE ,. ..*---RE --LE

rv 2S ---- ---- _

Li!-u--r...u._

FIG. 6 Clinical PTG pressure recordings in three postures-(a) sitting, (b) supine, (c) sitting

Groups

2(I 5i eyes)

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Rapid pneumatic and Mackay-Marg applanation tonometry 69I

Table II Mean rise in intraocular pressure in various age groups from sitting to supine (2 minutes)posture in group 2 and 3 as recorded by PTG and Mackay-Marg tonometer

Mean postural change (sitting to supine 2 min)

No. of eyes Group 2 Group 3 Pneumatonograph

Group 2 Group 3

2022

5477788

259

'4

i83352322

'5

Mean

64

2125466

2-78I .872.732.793'093.00

2-834.004 20

4.804' 1034 I7

2'71 4°04

Mackay-Marg

Group 2 Group 3

2 542'00

2-322'452-852.95

2-92

3.754-244-674-243.2I

2.5I 3,72

SEM SD

SEM=:Standard error of meanS D = Standard deviation

PneumatonaqgraphMackay-Marg

FIG. 7 Frequency distribution histogram of change inpressure from sitting to supine (two minutes) in relationto age groups in Groups 2 and 3 by PTG andMackay-Marg tonometer

glaucomatous patients was there any fall in pressurewhen in the supine position.On the whole, the increase most frequently

ng observed in Group 2 was of i to 2mmHg in40 per cent by the PTG and in 46 per cent by theMackay-Marg, whereas in Group 3 it was 2 to3 mmHg. In Group a, an increase in pressure of

ine S mmHg or more was observed in I2-67 per centn using the PTG and 9 34 per cent using the Mackay-

Marg, whereas in Group 3 it was 25 and 27-78per cent, suggesting higher frequency of highpostural change in glaucomatous patients com-

inc pared with non-glaucomatous subjects.

DiscussionThe first indentation tonometer was introduced bythe Utrecht School, but the most reliable instrumentduring the first half of the twentieth century was un-

w doubtedly the Schiotz (I909). Weighted applanationtonometry was first conceived by Maklakoff in I885and a resurgence of interest in applanation tono-metry in the more scientific form (Goldmann, 1957)

q9 greatly improved the accuracy of this form ofmeasurement. Both indentation and Maklakoffapplanation tonometry are carried out when thepatient is lying down. Goldmann applanationtonometry, on the other hand, is carried out when

mg the patient is erect. For this, among other reasons,it is difficult to compare the two methods. Aninvestigation of this difference has led to thediscovery that postural pressure changes occur,but that both the Mackay-Marg tonometer and thepneumatonograph operate independently of posture.

Tierney and Rubin (I966) showed that theMackay-Marg tonometer corresponds with theGoldmann applanation method to within 2 mmHg.The work of Quigley and Langham (I975) and Jainand Marmion (1976) has shown that the PTG and

Age groups

30 to 3940 to 49

50 tO 596o to 6970 tO 798o+

Total io8 i6-26 24 54 I1531 23'03

20-80 2*470 4-8021-84 2s534 4-9517-30 0s546 3 0717*92 0-602 3 1525s69 3 74 4 6b6 126*78 3 - 82 1 6-892408 2-613 5s18246 3 2 598 4-9820*01 0*662 3 4 720-43 0 691 3 6429-73 3- 89 1 7 14305O 3j3735 7'3623 62 2-542 5-0324'08 2 661 5 1419*75 0 651 3 4220 13 0*631 3-3129-04 3 782 7-0s29 54 3 472 6-9223 10 2 513 4-9923 5 2'580 4-7 519 31 0-640 3.39208 1 0o611 36128-40 38 1 1 69828'68 3 780 780119 48 2 42 1 4.7220 55 2 46 1 45016s54 0-s2 4 3 0716 82 0s542 3-1924 98 3 691 6-7925 76 3- 740 6s5419 48 2 402 4 7 220-03 2-36 1 4-8316 15 0o514 29916 82 0-49 8 2-762413 3686 65224*83 3 - 562 6 40

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692 British Journal of Ophthalmology

Table III Comparative figures of postural increase in intraocular pressure as observed by various workers

Mean IOPNo. of while sittingeyes (mmHg)

Armaly and Salamoun (I963)Galin and others (I963)Robert and Rogers (I964)Hetland-Eriksen (I966a)Tarkkanen and Leikola (I967)Krieglestein and Langham (1975)

Jain and Marmion (1976)Group IGroup 2

Group 3

Groups 2 and 3

7640'5'76749o3220

'4.7315-63i8-8o32-5715 014.0I7028-9

40 I5-65I51 17.30

17.92Io8 25-69

26-78259 20-80

2zI.84

Goldmann readings correspond in normal eyes towithin less than i mmHg. The current study onintraocular pressure on 259 eyes using the PTGand the Mackay-Marg indirectly confirmed theseobservations and showed that the mean readingusing the Mackay-Marg was higher by "13 mmHgthan that of the PTG. Consistency of readings ineach instrument served as a cross check on thepostural change in intraocular pressure.There is a significant increase in intraocular

pressure when a normal subject changes fromsitting to lying down. Although Fig. 4 and Table Iindicate that there is some degree of a decrease inpressure within five minutes of assuming therecumbent posture, a sample of 15 patients (30 eyes)after the initial five-minute period showed a degreeof consistency in the recordings which suggeststhat any fall occurring after that time would beslight. A reduction in the degree of increase inintraocular pressure is mitigated by adoption of asemi-recumbent position (one pillow) which raisesthe head to about fifteen degrees, and a return tothe original or less than the original pressure occurson resuming the erect posture.The rise in intraocular pressure is dependent

partly on the initial intraocular pressure, but thisincrease is significantly higher in the 50 to 79 yearage group. This takes into account the rectificationrequired for disparity in numbers, the proportionof women to men, and the initial difference inintraocular pressures. The results for young peoplecorrelate well with those of Tarkkanen and Leikola(I967), although the average age was higher in theirreport and the mean intraocular pressure slightlylower (Table III). In the older age group compar-able to the distribution in chronic simple glaucoma,

Mean increasein pressure(mmHg)

2 633'042'204.74I 402.504'305.00

I 402.712.514°043 723-282.79

Instrument used

Sitting

GoldmannGoldmannGoldmannGoldmannMackay-MargPTGPTGPTG

PTGPTGMackay-MargPTGMackay-MargPTGMackay-Marg

Recumbent

Goldmann (lying on side)Goldmann (lying on side)Goldmann (supine)Goldmann (lying on side)Mackay-Marg (supine)PTG (supine)PTG (supine)PTG (supine)

PTG (supine)PTG (supine)Mackay-Marg (supine)PTG (supine)Mackay-Marg (supine)PTG (supine)Mackay-Marg (supine)

the results obtained confirm those published byArmaly and Salamoun (I963), Galin and others(I963), and Robert and Rogers (I964). The meanpostural pressure changes were higher than in theGroup 2 reported here, particularly in the recum-bent position, partly because the patients wereexamined lying on their sides. The results of Quigleyand Langham (I975) are uniformly higher forwhich there is at present no explanation.The principal postural changes in circulatory

dynamics are related to changes in the blood volumewhich decreases in the erect posture after about 30minutes as a result of hydrostatic capillary changes.There is a fall in blood pressure in recumbencyassociated with increased minute volume whichoccurs rapidly, usually within 30 seconds. Therapidity with which the intraocular pressureincreases in the recumbent position would indicatethat this is a reflex phenomenon governed by abaroreceptor type mechanism, and the fine adjust-ment that can occur in time and on adjustment ofposture supports this hypothesis. Hydrostaticchanges as mediated through venous pressure,capillary perfusion, and blood volume movements,would take longer to produce an effect by change*n posture. Age would also tend to accentuate thischange and if the baroreceptor mechanism werethe basis for it, it would be expected that this wouldincrease with age.The mean postural change in glaucomatous

patients is significantly higher than in the non-glaucomatous group. This is basically in agreementwith the work of Hetland-Eriksen (i966a) andKrieglestein and Langham (I975), but it wasneither universal nor uniform (Fig. 7); 8 per centof glaucomatous eyes had no change in intraocular

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Rapid pneumatic and Mackay-Marg applanation tonometry 693

pressure, 24 per cent had an increase which waswithin the bounds noted on a normal gaussiancurve, and an increase in intraocular pressure ofmore than 5 mmHg was observed approximatelythree times more frequently in glaucomatous thanin non-glaucomatous eyes. The maximum riserecorded by us was Io mmHg in glaucomatouseyes and 8 mmHg in non-glaucomatous eyes. Theglaucomatous eyes take longer to adjust after therise, as shown by the divergence of results in thesemi-recumbent to erect posture. This reflects theinability of the glaucomatous eye to compensatefor change in pressure and offers a simple testingmethod for potential glaucomatous change inaqueous humour dynamics. If the postural changesin pressures are going to be used as a diagnosticprocedure in glaucoma, it is important to take intoaccount that aspect of the orientation of thepressure, particularly if the postural rise has notbeen very remarkable.Four further clinical aspects of the postural rise

merit consideration. First, the role posture canplay in the production of change at the optic discin cases of glaucoma and so-called low-tensionglaucoma where the increased intraocular pressurewhen lying down is associated with a fall in bloodpressure, although this may be partly mixigated bya slightly increased blood volume. Secondly,medical treatment cannot be regarded as beingsuccessful unless the highest intraocular pressurecan be contained within nornal limits for a particu-lar eye. This is so for stressful conditions, diurnalrises, and also postural changes in pressure. Thirdly,the effect of surgery on the postural rise is importantbecause of the initial reverse effect during theactual operative procedure and, also in the eventof surgery proving better in controlling theglaucomatous rise in recumbency, it would be an

indication for opting for this course of treatment.Finally, the postural pressure rise should be ofconsideration in all intraocular operations and maypossibly account for some of the vitreous problemssuch as vitreous upthrust in cataract surgery.The mechanism of the glaucomatous postural

change should be examined further in conjunctionwith phasic variation, plasma cortisone fluctuation,and other hydrostatic mechanisms. Such investi-gations could possibly give some indication to thebasic mechanism of the response and the variationthat occurs.

SummaryA postural study was conducted in three separategroups of subjects. The first group comprised 20women volunteers with an average age of 20-75years. In this group, the study was conducted bythe pneumatonograph only. Mean pressure recordedwas I5 65 ±0.25 mmHg and there was an averagerise of I 4 mmHg in supine posture.Groups 2 and 3 comprised i 51 non-glaucomatous

and Io8 glaucomatous eyes respectively in the agerange of 30 to 85 years. In these two groups, thestudy was conducted using the PTG and theMackay-Marg tonometer. Clinical evaluation of theMackay-Marg with the PTG gave significantcorrelation, with mean Mackay-Marg readingsbeing I*I3 mmHg higher.The intraocular pressure when changing from

seated to the supine position increased on averageby 2-7I and 4-04 mmHg, respectively in Groups 2and 3 and by 25 i and 3 72mmHg by Mackay-Marg,suggesting a higher change in glaucomatoussubjects. Pressure on resumption of sitting wasfound to be lower than the initial pressure. Posturalchange also showed some direct relationship withage in non-glaucomatous subjects.

ReferencesANDERSON, D. R., and GRANT, W. M. (1973) Invest. Ophthal., 12, 204ARMALY, M. F., and SALAMOUN, S. G. (I963) Arch. Ophthal., 70, 603BEST, M., and ROGERS, R. (1974) Ibid., 92, 54GALIN, M. A., MCIVOR, J. w., and MAGRUDER, G. B. (I963) Amer. J. Ophthal., 55, 720GOLDMANN, H. (1957) In 'Glaucoma' (Transactions of the Second Conference I956). Macy Foundation, New YorkHETLAND-ERIKSEN, J. (Ig66a) Acta ophthal. (Kbh.), 44, 515

(i966b) Ibid., 44, 522INGLIMA, R. (I966) Eye, Ear, Nose Thr. Monthly, 45, 64IRVINE, A. R., and KAUFMAN, H. E. (I969) Amer..7. Ophthal., 68, 835JAIN, M. R., and MARMION, V. J. (I976) Brit. 7. Ophthal., 6o, 107KAUFMAN, H. E., WIND, C. A., and WALTMAN, S. R. (I970) Amer. Y. Ophthal., 69, 1003KRIEGLESTEIN, G. K., and LANGHAM, M. E. (1975) Ophthalmologica (Basel), 171, 132LANGHAM, M. E., and MCCARTHY, E. (I968) Arch. Ophthal., 79, 389MAKLAKOFF (i885) Arch. Ophtal. (Paris), 4, 159QUIGLEY, H. A., and LANGHAM, M. E. (1975) Amer.J. Ophthal., 80, 266ROBERTS, w., and ROGERS, J. W. (I964) Ibid., 57, IIISCHI6TZ, H. (I909) Arch. Augenheilk,. 62, 317TARKKANEN, A., and LEIKOLA, j. (1967) Acta ophthal. (Kbh.), 45, 569TIERNEY, J. P., and RUBIN, M. L. (1966) Amer. 7. Ophthal., 62, 263

ci

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pressure.the postural effect on intraocularapplanation tonometry to evaluate Rapid pneumatic and Mackey-Marg

M R Jain and V J Marmion

doi: 10.1136/bjo.60.10.6871976 60: 687-693 Br J Ophthalmol 

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