This manuscript is a guide to using the Goldmann Applanation Tonometry Eye (GATE), This device permits the student to learn applanation tonometry Without the anxiety of using human subjects. Detailed instructions accompanied by photographs are presented. A brief theoretical discussion of Goldmann applanation tonometry is included

Colvin, John W

English

CommonKnowledge

Pacific University 
CommonKnowledge 
College of Optometry Theses, Dissertations and Capstone Projects 
5-1989 
Goldmann applanation tonometry eye procedures manual 
John W. Colvin 
Pacific University 
Recommended Citation 
Colvin, John W., "Goldmann applanation tonometry eye procedures manual" (1989). College of Optometry. 
873. 
https://commons.pacificu.edu/opt/873 
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Goldmann applanation tonometry eye procedures manual 
Abstract 
This manuscript is a guide to using the Goldmann Applanation Tonometry Eye (GATE), This device 
permits the student to learn applanation tonometry Without the anxiety of using human subjects. Detailed 
instructions accompanied by photographs are presented. A brief theoretical discussion of Goldmann 
applanation tonometry is included. 
Degree Type 
Thesis 
Degree Name 
Master of Science in Vision Science 
Committee Chair 
Lee Ann Remington 
Subject Categories 
Optometry 
This thesis is available at CommonKnowledge: https://commons.pacificu.edu/opt/873 
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GOLDMANN APPL,ANATION TONOMETRY EYE 
PROCEDURES MANUAL 
By 
JOHN W. COLVIN 
A the$iS submitted to the faculty of the 
College of Optometry 
Pacific University 
Forest Grove, Oregon 
for the degree of 
Doctor of Optometry 
May, 1989 
Adviser: 
Lee Ann Remington, o. D. 
Sighature Page 
N ~-.. 
Author: u...o-J; ~~- -'--...,....,..--"-.--.,.--- John W. Colvin 
Lee Ann Remington, 0. D. 
BIOGRAPHY 
John W. Colvin received his Bachelor of Science degrees from 
Colorado State University (Fort Collins, Colorado) in Microbiology and 
Biology. Following this edWcation, he was a Research Microbiologist for 
the Environmental Protectic)ll Agency in Fairbanks, Alaska investigating 
bacterial growth dynq,rnics following infusion of crude oil into 
subarctic river water. Results of this study were presented to the 
Alaska Conference on PQI(,;I,r Studies which was internationally attended 
by arctic researchers. 
For eight years, as head chemist for the City of Loveland in 
Colorado, his activities Included supervision of the laboratories and 
representation for the City !n state and local water quality issues. 
During this time, he was also an instructor for the Colorado Department 
of Health teaching wat~r and wastewater treatment theory and 
mathmatics for which he received the Award for Outstanding Teaching 
Service given by the Department of Health. 
While in optometry school at Pacific. University, he has joined many 
optometric organizations including the AOA, Contact Lens Section, Low 
Vision Section, Colorado Optometric Association, and COVD. In 
addition, he has been accepted into the BSK organization. His 
preceptorship was at Fit:z:simon's Army Hospital in Aurora, Colorado 
followed by a preceptorship at a private optometric clinic in the same 
city. 
He is married to Sus~n and has three children: Bennett, Grant, and 
Matthew. 
ABSTRACT 
This manuscript is q guide to using the Goldmann Applanation 
Tonometry Eye (GATE), This device permits the student to learn 
applanation tonometry Without the anxiety of using human subjects. 
Detailed instructions accompanied by photographs are presented. A 
brief theoretical discussion of Goldmann applanation tonometry is 
included. 
ACJ<NOWU:DGIVIENTS 
I wish to extend my sincere thanks to Dr. Lee Ann Remington for her 
suggestions and willingness to accept another thesis student. 
Gratitude is expressed to br. Nada Lingel for her many useful 
suggestions and slides. My wife, Susan, and kids (Bennett, Grant, and 
Matthew) are thanked for providing the important balance between 
profession and life. 
This manuscript is primarily a guide to using the Goldmann 
Applanation Tonometry Eye (<3A TE). Procedures discussed here do not 
supplant didactic or clinical instruction an individual receives in 
formal training for human eye applanation tonometry. The GATE does 
provide the student with a means of practicing his/her first attempts 
at applanation tonometry under conditions far less anxious than if 
using human subjects. 
The GATE is constructed of a plastic body, posterior 1-way air 
valve, and anterior membrfiine. The membrane, cut from a latex ballon, 
simulates the human cornea for training purposes. After spraying the 
membrane with the *fluorescein solution, visualization of the ghost 
rings and applanation mires is fairly effective with the GATE. The 
GATE is secured to a WQ¢den support bar that is attached to the slit 
lamp. 
Utilizing the GATE requires E> steps: 
(1) Secure the membrane with an 0-ring. 
(2) Inflate the GATE. 
(3) Attach the wooden GATE support to the slit lamp. 
(4) Secure the GATE to the wooden support. 
(5) Apply the fluorescein Solution with the spray bottle. 
(6) Perform applanation tonometry. 
*The fluorescein solution wAs formulated using Crystal Clear® lens 
cleaner in which approximately 20 FUL-GLO® fluorescein strips were 
rinsed several times. 
Secure the membranes 
Stretch one latex membrane over the open end of the GATE body. 
While maintaining tension, roll an 0-ring over the membrane and down 
about 1/2". Roll a second 0-ring over the membrane to further secure 
the membrane. If nece$sary, tug at the loose edges of the membrane to 
smooth it out so that folds and wrinkles are not present. 
Inflate the GATE 
Insert the ball inflating needle into the 1-way valve and inflate 
with the air pump. This may take some practice and trial and error to 
find an acceptable amount of inflation .. Care must be exercised not to 
overinflate so as to force the membrane out from under the 0-rings. 
Secure the GATE to the WOoden suppQrt 
Place the GATE in the the center of the support and stretch a rubber 
band over it. 
Attach wooden GATE support to the slit lamp 
The wooden GATE support is attached to the patient side of the slit 
lamp chin rest support arms with heavy duty rubber bands. A rubber 
band is stretched from each end hook, around a chin rest support arm, 
and back to the end hook. 
Spray the GATE membranes with the fluorescein solution 
The membrane is sprayed with a fluorescein-detergent solution just 
prior to performing applanation tonometry. Use only enough spray to 
achieve adequate coverage. Do not wait too long before tonometry or 
the solution film will dry. 
Clinicians are frequently $Urprised that applanation tonometry can 
be performed without fluorescein, but unfortunately it has been 
demonstrated that this technique underestimates lOP by an average of 
5.62mm Hg (Roper 1980). 
Perform applanation tonometry 
1. Set up the slit lamp with a bright, wide cobalt beam. The 
illumination arm is positioned at approximately 45°. Set 
magnification at about 15X. Position the Goldmann probe facing 
forward. Adjust the probe measurement dial to about 1 Omm Hg. 
2. Looking outside of the instrument; align the probe at the apex 
of the membran¢ using the vertical control of the slit lamp. 
3. Observing through the oculars, advance the probe toward the 
GATE. 
4. Notice, if you are properly lined up, blue 'ghost' rings (Figure 
1) will come into view and may be used to improve alignment by 
centering these rings before coming into contact with the eye. 
5. Yellow mires suddenly come into view when the probe touches 
the eye or 'tear film' of the eye. Appropriate alignment of the 
mires has occured when they have just overlapped (Figure 2). If 
the mires are widely overlapped (Figure 3), the measuring dial 
on the tonometer housing must be turned down as the pressure 
in the eye is leps than the apposition force of the probe. ' 
Conversely, if the mires are separated from each other (Figure 
4) the dial must b~ turned up to increase the applanating force. 
If the probe is not 9entered properly (Figure 5), it is necessary 
to move it toward the l~rger of the mires. 
6. Withdraw the probe straight back after aligning the mires. 
7. Always disinfect the probe appropriately, e.g. alcohol 
wiping, before usinQ on hurnan subjects. 
Additional notes: 
*Move the slit lamp controls around to get a feel for how the mires can 
be centered. If you see mires but the adjusting dial does not change 
their position, then you rnay need to move the probe forward just 
slightly with the joy stiGk to achieve contact with the membrane. 
*If the mires are underlapped and you can't get overlapping then the 
GATE has too much pressure in it. It must be reinflated with less 
pressure. 
*The GATE is not intended to be a calibrating device for standardizing 
applanating devices. 
Observation of Mires 
Figure 1. Ghost rings seen just before 
contacting the membrane. 
Figure 2. Yellow mires correctly overlapped 
for measurement of lOP. 
Figure 3. Mires overapplanated--applanation 
pressure must be reduced to achieve 
correct overlapping. 
Figure 4. Mires underapplanated--applanation 
pressure must be increased. 
Figure 5. Mires off-center--move probe in 
direction of most extensive mire to 
achieve correct centering. 
Theoretical considerations of Goldmann applanation 
tQnometry 
Most tonometers requir~ the use of a force applied to the eye and 
the simultaneous measurement of the deformation produced (Chandler 
and Grant 1979). The principle of Goldmann applanation tonometry 
employs a standard deformation and the force needed is quantified. Its 
utility is based on a modification of the lmbert-l=ick Law. The basic 
law states that an external force (W ) against a sphere equals the 
pressure in the sphere (P t) times the area flattened (applanated) by 
the external force (A ) (Figure 6). 
W = P1xA 
This formula is correct if the sphere conforms to the following 
criteria: It is (1) exactly spherical, (2) completely flexible, (3) 
infinately thin, and (4) dry. Of course, the human cornea (or any other 
cornea) fails to meet those criteria, therefore it is necessary to 
modify the formula. Additional considerations must include the fact 
that the cornea is wet and therefore has an inherent surface tension 
(S) which tends to pull the applanating surface onto the cornea. The 
rigidity (B ) of the cornea requires that a force bend it. Since the 
cornea has a measurable thickness (approximately 0.55mm) an 
applanating force will result in a larger outer area of flattening (A ) 
than the inner flattened area (A 1 } (Figure 7). It has been shown that 
central corneal thickness has a positive correlation to lOP. Thick 
corneas translate to higher applanation measurements (Ehlers and 
Bramsen 1975). Goldmann applanation tonometry may thus be described 
by a modification of the lmbert-Fick Law: 
W+S=P1A1 +B 
I mbert -Fi ck Lew 
w 
1 
__ ... ,. ....... _ ..... 
.. , 
Figure 6 
Forces Affecting Applenetion Tonometry 
w 
B 1 B 
tear meniscus Al 
~ / 
Figure 7 
A study of the excised human cornea mounted on a chamber 
connected to a manometer reservoir confirmed that applanation 
tonometry is represented by the modified lmbert-Fick Law provided 
that the diameter of the external applanated area is 3.06mm 
(Gloster and Perkins, 196~). 
BIBLIOGRAPHY 
Chandler, P. A., Grant, W. M. Glaucoma, 2nd Ed., Lea and Febiger, 1979. 
Ehlers, N. and Bramsen, T; Acta Ophthalmology, supp., Vol. 125, 32, 
1975. 
Gloster, J. and Perkins, E. $., Experimental Eye Research, Vol. 2, 274, 
1963. 
Gloster, J. Tonometry and Tonography. Little, Brown, and Co. Vol. 5, No. 
4, Dec. 1965. 
Roper, D. L., American Journal of Ophthalmology, 90, 668-671, Nov. 
1980. 


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