Glaucoma

1. Intraocular Pressure and
Aqueous Humor Dynamics
AAO READING GLAUCOMA
FARADHILLAH A. SURYADI

2. - An understanding of aqueous humor dynamics is essential for the
evaluation and management of glaucoma.
- Aqueous humor is produced in the ciliary pro cesses at 2-3 uL/min
diurnally (and approximately 50% less nocturnally) and drains through the
trabecular and uveoscleral pathways.
- The parameters that contribute to intraocular pressure (IOP) are modeled
by the modified Goldmann equation; they include outflow facility, aqueous
humor production rate, episcleral venous pressure, and uveoscleral
outflow rate.
- IOP is found in the population in a skewed distribution, and glaucoma can
occur at any pressure level.
- Various tonometry methods can be used to estimate IOP, but all of the
devices have inherent sources of measure ment error.
HIGHLIGHTS

3. Aqueous Humor Production
- produced by the ciliary processes at an average rate of 2–3 μL/min when awake,
decreasing about 50% during sleep.
- The ciliary body contains about 80 ciliary processes : composed of a double layer of
epithelium over a core of stroma and a rich supply of fenestrated capillaries
- Capillaries are supplied mainly by branches of the major arterial circle of the iris.
- The apical surfaces of the outer pigmented and inner nonpigmented epithelial cell
layers face each other.
- The nonpigmented epithelial cells are joined by tight junctions, which are an
important component of the blood–aqueous barrier.
- The inner nonpigmented epithelial cells, which protrude into the posterior chamber,
contain numerous mitochondria and microvilli; these cells are thought to be the
actual site of aqueous production.
- The ciliary processes provide a large surface area for secretion.
AQUEOUS HUMOR PRODUCTION AND COMPOSITION

4. Aqueous humor enters the posterior chamber via the following physiologic
mechanisms:
• active secretion, which takes place in the double-layered ciliary epithelium
• ultrafiltration
• simple diffusion
Active secretion refers to transport that requires energy to move sodium, chloride,
bicarbonate, and other ions, against an electrochemical gradient. Active secretion is
independent of pressure and accounts for the majority of aqueous production. It
involves activity of the enzyme carbonic anhydrase II.
Ultrafiltration refers to a pressure-dependent movement along a pressure gradient. In
the ciliary processes, the hydrostatic pressure difference between capillary pressure
and IOP favors fluid movement into the eye, whereas the oncotic gradient between the
two resists fluid movement.
Diffusion involves the passive movement of ions, based on charge and concentration,
across a membrane.
AQUEOUS HUMOR PRODUCTION AND COMPOSITION

5. - In humans, aqueous humor has an excess of hydrogen and chloride ions, an excess
of ascorbate, and a deficit of bicarbonate relative to plasma.
- Aqueous humor is essentially protein free (1/200–1/500 of the protein found in
plasma), allowing for optical clarity and reflecting the integrity of the blood–aqueous
barrier of the normal eye. Albumin accounts for approximately half of the total
protein.
- Other components of aqueous humor include growth factors; several enzymes, such
as carbonic anhydrase, lysozyme, diamine oxidase, plasminogen activator, dopamine
b-hydroxylase, and phospholipase A2; and prostaglandins, cyclic adenosine
monophosphate, catecholamines, steroid hormones, and hyaluronic acid.
- Aqueous humor composition is altered as it flows from the posterior chamber,
through the pupil, and into the anterior chamber. This alteration occurs across the
hyaloid face of the vitreous, the surface of the lens, the blood vessels of the iris, and
the corneal endothelium; and it is secondary to other dilutional exchanges and
active processes.
AQUEOUS HUMOR PRODUCTION AND COMPOSITION

8. Inhibition of the enzyme carbonic anhydrase suppresses aqueous humor formation.
However, the precise role of carbonic anhydrase has been debated vigorously. Its
function may be to provide the bicarbonate ion, which, evidence suggests, is actively
secreted in human eyes. Carbonic anhydrase may also provide bicarbonate or hydrogen
ions for an intracellular buffering system.
Aqueous humor formation may be reduced by the blockade of b2-receptors, which
are the most prevalent adrenergic receptors in the ciliary epithelium and which may
affect active secretion by causing a decrease either in the efficiency of Na+, K+-
ATPase or in the number of pump sites. For additional discussion of the sodium pump
and the pump–leak mechanism. Stimulation of a2-receptors also reduces aqueous
humor formation, possibly via a reduction of ciliary body blood flow mediated through
inhibition of cyclic adenosine monophosphate (cAMP); the exact mechanism is unclear.
SUPPRESSION OF AQUEOUS FORMATION

9. The most common method used to measure the rate of aqueous formation is
fluorophotometry. For this test, fluorescein is administered systemically or topically, its gradual
dilution in the anterior chamber is measured optically, and change in fluorescein concentration
over time is then used to calculate aqueous flow. As previously noted, the normal flow is
approximately 2–3 μL/min, and the aqueous volume is turned over at a rate of approximately 1%
per minute. The measurement of aqueous humor flow rate is assumed to be equal to the rate of
aqueous production by the ciliary processes at steady state.
The rate of aqueous humor formation varies diurnally and decreases by half during sleep. It
also decreases with age. The rate of aqueous formation is affected by a variety of factors, including
the following:
• integrity of the blood–aqueous barrier
• blood flow to the ciliary body
• neurohumoral regulation of vascular tissue and the ciliary epithelium
Aqueous humor production may decrease after trauma or intraocular inflammation and after
the administration of certain drugs (eg, general anesthetics and some systemic hypotensive
agents). Carotid occlusive disease may also decrease aqueous humor production.
MEASUREMENT OF AQUEOUS FORMATION

10. Trabecular Outflow
The trabecular
meshwork is
classically divided
into 3 layers: uveal,
corneoscleral, and
juxtacanalicular.
AQUEOUS HUMOR OUTFLOW
Aqueous humor outflow occurs by 2 major mechanisms: (1) the pressure- sensitive
trabecular (or conventional) pathway and (2) the pressure-insensitive uveoscleral (or
unconventional) patthway.

11. The trabecular meshwork is composed of multiple layers, each of which consists of
a collagenous connective tissue core covered by a continuous endothelial layer. The
trabecular meshwork is the site of pressure-sensitive outflow and functions as a one-
way valve, permitting aqueous to leave the eye by bulk flow but limiting flow in the
other direction, independent of energy. Its cells are phagocytic, and they may exhibit
this function in the presence of inflammation and after laser trabeculoplasty.
In most eyes of older adults, trabecular cells contain a large number of pigment
granules within their cytoplasm that give the entire meshwork a brown or muddy
appearance. There are relatively few trabecular cells—approximately 200,000–300,000
cells per eye. With age, the number of trabecular cells decreases, and the basement
membrane beneath them thickens, potentially increasing outflow resistance. An
interesting effect of all types of laser trabeculoplasty is that it induces division of
trabecular cells and causes a change in the production of cytokines and other
structurally important elements of the extracellular matrix. The extracellular matrix
material is found through the dense portions of the trabecular meshwork.

12. The Schlemm canal is completely lined with an endothelial layer that rests on a
discontinuous basement membrane. The canal is a single channel, typically with a
diameter of about 200–300 μm, although there is significant variability; it is traversed by
tubules. The exact path of aqueous flow across the inner wall of the Schlemm canal is
uncertain. Intracellular and intercellular pores suggest bulk flow, while so-called giant
vacuoles that have direct communication with the intertrabecular spaces suggest active
transport but may be artifacts. The outer wall of the Schlemm canal is formed by a
single layer of endothelial cells that do not contain pores. A complex system of vessels
connects the Schlemm canal to the episcleral veins, which subsequently drain into the
anterior ciliary and superior ophthalmic veins. These, in turn, ultimately drain into the
cavernous sinus.
The trabecular outflow pathway is dynamic. With increasing IOP, the cross-
sectional area of the Schlemm canal decreases, while the trabecular meshwork
expands. The effect of these changes on outflow resistance is unclear.

14. A complex system of collector channels connects the Schlemm canal to the aqueous veins, which
in turn drain into the episcleral veins, forming the distal portion of the trabecular outflow system
(Video 2-1). The episcleral veins subsequently drain into the anterior ciliary and superior
ophthalmic veins. These, in turn, ultimately drain into the cavernous sinus.

15. Uveoscleral Outflow
In the normal eye, any nontrabecular outflow is termed uveoscleral outflow.
Uveoscleral outflow is also referred to as pressure-insensitive outflow. A variety of
mechanisms are likely involved, but the predominant one is aqueous passage from the
anterior chamber into the ciliary muscle and then into the supraciliary and
suprachoroidal spaces. The fluid then exits the eye through the intact sclera or along
the nerves and the vessels that penetrate it. There is evidence that outflow via the
uveoscleral pathway is significant in human eyes, accounting for up to 45% of total
aqueous outflow. Studies indicate that uveoscleral outflow decreases with age and is
reduced in patients with glaucoma. It is increased by cycloplegia, adrenergic agents, and
prostaglandin analogues but decreased by miotics. It is also increased by certain
complications of surgery and by cyclodialysis clefts. Uveoscleral outflow cannot be
measured noninvasively and is therefore calculated from the Goldmann equation.

16. The modified Goldmann equation summarizes the relationship between many of
these factors and the intraocular pressure (IOP) in the undisturbed eye:
P0 = (F – U)/C + Pv
where P0 is the IOP in mmHg, F is the rate of aqueous formation in microliters per
minute (μL/min), U is the rate of aqueous humor drainage through the pressure
insensitive uveoscleral pathway in microliters per minute (μL/min), C is the facility of
outflow through the pressure-sensitive trabecular pathway in microliters per minute
per mm Hg (μL/min/ mm Hg), and Pv is the episcleral venous pressure in mm Hg.
Resistance to outflow (R) is the inverse of facility (C). Figure 2-1 illustrates the impact
of reduced outflow facility (C value) of aqueous humor on IOP.
AQUEOUS HUMOR DYNAMICS

18. The most common method used to measure the rate of aqueous formation is
fluorophotometry. For this test, fluorescein is administered systemically or topically, its gradual
dilution in the anterior chamber is measured optically, and change in fluorescein concentration
over time is then used to calculate aqueous flow. As previously noted, the normal flow is
approximately 2–3 μL/min, and the aqueous volume is turned over at a rate of approximately 1%
per minute. The measurement of aqueous humor flow rate is assumed to be equal to the rate of
aqueous production by the ciliary processes at steady state.
The rate of aqueous humor formation varies diurnally and decreases by half during
sleep. It also decreases with age. The rate of aqueous formation is affected by a variety of factors,
including the following:
•integrity of the blood–aqueous barrier
•blood flow to the ciliary body
•neurohumoral regulation of vascular tissue and the ciliary epithelium
Aqueous humor production may decrease after trauma or intraocular inflammation and
after the administration of certain drugs (eg, general anesthetics and some systemic hypotensive
agents). Carotid occlusive disease may also decrease aqueous humor production.
MEASUREMENT OF AQUEOUS HUMOR PRODUCTION

19. The facility of outflow is the mathematical inverse of outflow resistance and varies widely in
normal eyes, with mean value ranging from 0.22 to 0.30 μL/min/mm Hg. Outflow facility decreases
with age and is affected by surgery, trauma, medications, and endocrine factors. Patients with
glaucoma and elevated IOP typically have decreased outflow facility.
Tonography is a method used to measure the facility of aqueous outflow. With this technique,
a weighted Schiøtz tonometer or pneumatonometer is placed on the cornea, acutely elevating the
IOP. Outflow facility in μL/min/mm Hg can be computed from the rate at which the pressure
declines with time, reflecting the ease with which aqueous leaves the eye.
Unfortunately, tonography depends on a number of assumptions (eg, ocular rigidity, stability
of aqueous formation, and constancy of ocular blood volume) and is subject to many sources of
error, such as patient fixation and eyelid squeezing. These problems reduce the accuracy and
reproducibility of tonography for an individual patient. In general, tonography is best used as a
research tool for investigating mechanisms of action of IOP changes and is rarely used clinically.
MEASUREMENT OF OUTFLOW FACILITY

20. Measurement of Uveoscleral Outflow Rate
Uveoscleral outflow rate cannot be measured noninvasively and, therefore, is
usually calculated from the Goldmann equation after determination of the
other parameters. There is evidence that outflow via the uveoscleral pathway
is significant in human eyes, account- ing for up to 45% of total aqueous
outflow, although invasive studies using tracers tend to report lower values.
Some studies indicate that uveoscleral outflow decreases with age and is
reduced in patients with glaucoma. It is increased by cycloplegia, adrenergic
agents, and prostaglandin analogues but decreased by miotics. It is also
increased by suprachoroidal stents and by cyclodialysis clefts

21. Measurement of Episcleral Venous Pressure
The episcleral veins are the ultimate destination for aqueous humor draining
through the trabecular pathway. Thus, the pressure in these veins, the
episcleral venous pressure (EVP), represents the lowest possible IOP in an intact
eye with normal aqueous humor produc- tion. It is a dynamic parameter that
varies with alterations in body position and systemic blood pressure. EVP is
often increased in syndromes with facial hemangiomas (eg, Sturge- Weber),
carotid-cavernous sinus fistulas, and cavernous sinus thrombosis; and it may be
partially responsible for the elevated IOP seen in thyroid eye disease. EVP may
also be altered by some medications, including topical Rho kinase inhibitors.

22. INTRA OCULAR PRESSURE
IOP Distribution and Relation to Glaucoma
Pooled data from large epidemiologic studies indicate
that the mean IOP in the general population of European
ancestry is approximately 15.5 mm Hg, with a standard
deviation of 2.6 mm Hg
The value 21 mm Hg (2 standard deviations above the
mean) was traditionally used both to separate normal
from abnormal pressures and to define which patients
required ocular hypotensive therapy.
Many patients with glaucoma consistently have IOPs ≤
21 mm Hg, and most individuals with IOP >21 mm Hg do
not develop glaucoma

23. INTRA OCULAR PRESSURE
IOP Distribution and Relation to Glaucoma
Intraocular pressure varies with a number of factors,
including the time of day (see the section “Circadian
variation”), heartbeat, respiration, exercise, fluid
intake, systemic medications, and topical medications .
Body position has a significant effect on IOP, and the
lowest IOP measurements are obtained when a person
is seated with the neck in neutral position. IOP is higher
when an individual is recumbent rather than upright,
predominantly because of an increase in the EVP.
Alcohol consumption causes a transient decrease in
IOP .
Cannabis also decreases IOP but has not proved
clinically useful because of its short duration of action
and its side effects.

24. Circadian variation
In individuals without glaucoma, IOP varies by 2–6
mm Hg over a 24-hour period, as aqueous humor
production, outflow facility, and uveoscleral
outflow rate change. Higher mean IOP is
associated with wider fluctuation in pressure. The
time at which peak IOP occurs varies among
individuals.
However, 24-hour IOP measurement performed
with individuals in their habitual body positions
(standing or sitting during the daytime and supine
at night) indicates that most people (with or
without glaucoma) have peak pressures during
sleep, in the early-morning hours, corresponding
with a decrease in aqueous humor production,
outflow facility, and uveoscleral outflow.
IOP fluctuation and glaucoma
A significant body of literature demonstrates an
association between IOP fluctuation and the risk
of glaucoma progression. However, the data are
largely retrospective, based on post hoc
analyses of IOP variations between visits in large
clinical trials. IOP fluctuation is also closely
correlated with the level of mean IOP and
appears to be a more important risk factor in
certain groups of patients, including those with
low IOP. Surgery results in less IOP fluctuation
than medical therapy, but the clinical
significance of this finding has not been
demonstrated.

25. CLINICAL MEASUREMENT OF IOP
Tonometry is the noninvasive
measurement of IOP. Many different
methods of tonometry have been
developed, and each has advantages
and disadvantages. All currently used
methods have sources of error, and no
device can accurately measure
intracameral pressure in all eyes.

26. Applanation Tonometry
Applanation tonometry, the most widely used method, is based on the Imbert-Fick principle, which
states that the pressure inside an ideal dry, infinitely thin-walled sphere equals the force necessary
to flatten its surface divided by the area of the flattening:
P=F/A
where P = pressure, F = force, and A = area. In applanation tonometry, the cornea is flattened, and
IOP is determined by measuring the applanating force and the area flattened. The Goldmann
applanation tonometer (Fig 2-5) measures the force necessary to flat- ten an area of the cornea
3.06 mm in diameter. At this diameter, the material resistance of the cornea to flattening is
counterbalanced by the capillary attraction of the tear film meniscus to the tonometer head.
Furthermore, the IOP (in mm Hg) equals the flattening force (in gram-force) multiplied by 10. A
split-image prism allows the examiner to determine the flattened area with great accuracy. Topical
anesthetic and fluorescein dye are instilled in the tear film to outline the area of flattening.
Fluorescein semicircles, or mires, visible through the split-image prism move with the ocular pulse,
and the endpoint is reached when the inner edges of the semicircles touch each other at the
midpoint of their excursion

27. The Perkins tonometer is a counterbalanced applanation tonometer that, like the
Goldmann tonometer, uses a split-image prism and requires instillation of fluorescein
dye in the tear film. It is portable and can be used with the patient either upright or
supine.
Applanation measurements are safe, easy to perform, and relatively accurate in most
clinical situations. Of the currently available devices, the Goldmann applanation
tonometer is the most widely used in clinical practice and research. Because
applanation does not displace much fluid (approximately 0.5 μL) or substantially
increase the pressure in the eye, IOP measurement by this method is relatively
unaffected by ocular rigidity, compared with indentation tonometry (see the section
“Indentation tonometry”).

30. The accuracy of applanation tonometry can be
reduced in certain situations (see Table 2-2,
which lists possible sources of error in
tonometry). An inadequate amount of
fluorescein can lead to poor visualization of the
mires and the measurement endpoint, resulting
in inaccurate readings. Tear film thickness can
also affect accuracy. A common misconception
is that a thick tear film leads to erroneous
readings because of excessively thick mires,
which require greater force to reach the
measurement endpoint.

31. Tonometry and Central Corneal Thickness
Measurements obtained with the most common types of tonometers are affected by
central corneal thickness (CCT). Goldmann tonometer readings are most accurate
when the CCT is 520 μm. Thicker corneas resist the deformation inherent in most
methods of tonometry, resulting in an overestimation of IOP, while thinner corneas
may give an artificially low reading. IOP may also be underestimated after laser or
other types of keratorefractive surgery if these procedures resulted in a CCT
significantly less than that assumed for Goldmann tonometry.

32. Mackay-Marg–type Tonometers
Mackay-Marg–type tonometers use an annular
ring to gently flatten a small area of the cornea. As
the area of flattening increases, the pressure in
the center of the ring increases as well and is
measured with a transducer. The IOP is equivalent
to the pressure when the center of the ring is just
covered by the flattened cornea. Portable
electronic devices of the Mackay-Marg type (eg,
Tono-Pen, Reichert Technologies; Fig 2-7A) contain
a strain gauge to measure the pressure at the
center of an an- nular ring placed on the cornea.

33. Pneumatonometer
The pneumatic tonometer, or pneumatonometer, is an
applanation tonometer that shares some characteristics
with the Mackay-Marg–type devices (Fig 2-7B). It has a
cylindrical air-filled chamber and a probe tip covered
with a flexible, inert silicone elastomer (Silastic
membrane) diaphragm. Because of the constant flow of
air through the chamber, there is a small gap between
the diaphragm and the probe edge. As the probe tip
touches and ap- planates the cornea, the air pressure
increases until this gap is completely closed, at which
point the IOP is equivalent to the air pressure. Similar to
the Tono-Pen, this instrument makes contact with only a
small area of the cornea and is especially useful in eyes
with corneal scars or edema and can be used with the
patient in sitting, lateral decubitus, or supine body
positions.

34. Noncontact (air-puff) tonometers
Noncontact (air-puff) tonometers determine IOP
by measuring the force of air required to indent
and flatten the cornea, thereby avoiding contact
with the eye. IOP is measured when the amount
of corneal indentation corresponds with the
maximum amount of light reflection from the
cornea. Readings obtained with these instruments
vary widely, and IOP is often overestimated.
Noncontact tonometers are often used in large-
scale glaucoma-screening programs or by
nonmedical health care providers.

35. Rebound tonometers
Rebound tonometry determines IOP by measuring
the speed at which a small probe pro- pelled
against the cornea decelerates and rebounds after
impact (Fig 2-7D). Rebound to- nometers are
portable, and topical anesthesia is not required;
these characteristics make them particularly
suitable for use in pediatric populations and for
home tonometry in some patients. However,
rebound tonometry is strongly influenced by
central corneal thickness, even when compared
with applanation tonometry. Thus, care must be
taken in the interpretation of IOP measurements
in eyes with thick or thin corneas.

36. Dynamic Contour Tonometers
The dynamic contour tonometer, a newer type of
nonapplanation contact tonometer, is based on the
principle that when the surface of the cornea is
aligned with the surface of the instrument tip, the
pressure in the tear film between these surfaces is
equal to the IOP and can be measured by a pressure
transducer. The tip is similar in shape and size to an
applanation tonometer tip, with a pressure
transducer placed in the center, and enables
measurement of ocular pulse amplitude in addition to
IOP. Evidence suggests that IOP measurements
obtained with dynamic contour tonometry may be
more independent of corneal biomechanical
properties and thickness than those obtained with
applanation.

37. Indentation Tonometry
Schiøtz tonometry determines IOP by
measuring the amount of corneal
indentation produced by a known
weight. Measurements are taken
with the patient supine, and the
amount of indentation is read on a
linear scale on the instrument and
converted to IOP by a calibration
table.

39. Tactile Tension
It is possible to estimate IOP by
digital pressure on the globe,
referred to as tactile tension. This
test may be useful in uncooperative
patients; however, the results may be
inaccurate even when the test is
performed by very experienced
clinicians. In general, tactile tensions
are useful only for detecting large
differences in IOP between a
patient’s 2 eyes.

40. Infection Control in Clinical Tonometry
Many infectious agents—including HIV, hepatitis C virus, and adenovirus—
can be re- covered from tears. Tonometers must be cleaned after each use
to prevent the transfer of such pathogens. For Goldmann-type and Perkins
tonometers, the tonometer tips (prisms) should be cleaned immediately
after use. The ideal method for disinfection is controversial. Sodium
hypochlorite (dilute bleach) offers effective disinfection against adenovirus
and herpes simplex virus, the viruses commonly associated with
nosocomial outbreaks in eye care. In contrast, alcohol wipes or soaks do
not appear to be effective at eradicating all infectious virions. The efficacy
of other disinfection protocols has not been adequately evaluated.

41. SOAL

42. Seorang pria berusia 50 tahun datang ke klinik mata dengan keluhan
penglihatannya menurun secara bertahap sejak beberapa bulan yang
lalu. Mata terkadang merah dan nyeri. VODS : 20/60, TIO : 35/29 mmHg.
Funduskopi kedua mata menunjukkan papil optik yang pucat dan
ekskavasi yang dalam. Pasien memiliki riwayat penggunaan obat
glaukoma.
Apa nama enzim yang dihambat oleh obat anti-glaukoma yang dapat
menurunkan produksi humor aqueous?
A. Karbonik anhidrase D. Fosfodiesterase
B. Amilase E. Tirosin kinase
C. Siklooksigenase
1

43. Enzim tersebut terlibat pada mekanisme fisiologis aqueous humor
masuk kedalam posterior chamber. Mekanisme fisiologis apakah yang
dimaksud?
A. Difusi, yaitu pergerakan HA melewati membrane berdasarkan derajat
konsentrasi
B. Ultrafiltrasi, yaitu pergerakan HA berrgantung pada besar tekanan
C. Ultraclarity, yaitu pergerakan HA berdasarkan kejernihan HA
D. Sekresi Aktif, pergerakan HA melawat gradien elektrokimia dengan
menggunakan energi
E. Sekresi Pasif, pergerakan HA mengalir tanpa adanya sebuah gaya
usaha dan bergantung pada enzim.
2

44. Manakah pernyataan berikut yang tidak sesuai dengan produksi humor
aqueous?
A. Penurunan produksi HA berkurang saat tidur
B. Dipengaruhi oleh integritas blood-aqueous barrier
C. Penyakit oklusi carotis dapat meningkatkan produksi HA
D. Produksi bergantung pada aliran darah ke corpus siliaris
E. Pemberian obat anti hipertensi dapat menurunkan produksi HA
3

45. Pasien wanita umur 50 tahun datang dengan keluhan sering nyeri kepala
dan mata sebelah kiri disertai penglihatan kabur. Pasien tidak pernah
berobat sebelumnya. Pada pemeriksaan oftlamologi didapatkan visus
VOD : 20/20, VOS : 20/80 dan TIO 12.14.13/34.36.32 dengan I-care.
Faktor apa yang mungkin meningkatkan tekanan intraocular pasien?
A) Jogging
B) Mengonsumsi alcohol
C) Mengonsumsi kortikosteroid
D) Kehamilan
E) Bersepeda
4

46. Dari gambar dibawah, manakah gambaran Goldman tonometry mires
yang kita harapkan ?
A. B. C. D. E.
5

47. Dari gambar dibawah, manakah gambaran Goldman tonometry mires
dengan high IOP?
A. B. C. D. E.
6

48. _________ mengukur IOP dengan mengukur gaya udara yang
diperlukan untuk meratakan kornea sedangkan ____________
mengukur IOP dengan mengukur kecepatan probe yang
dipantulkan setelah menabrak kornea
A) Tonometer Mackay-Marg, Pneumatonometer
B) Tonometer nonkontak, Tonometer Rebound
C) Tonometer nonkontak, Tonometer Mackay-Marg
D) Tonometer rebound, Pneumatonometer
E) Pneumatonometer, Tonometer rebound
7

49. Apa kelemahan potensial dari tonometer nonkontak dalam
pengukuran IOP?
A) Tidak akurat pada mata dengan bekas luka kornea atau
edema
B) Memerlukan anestesi topikal
C) Memerlukan baterai untuk menggunakan alat
D) Probe hanya sekali pakai
E) Tidak dapat digunakan pada anak
8

50. Telah dilakukan pemeriksaan TIO dengan
menggunakan Schiotz dengan plunger 5.5
gr. Dengan menggunakan table konversi,
berapakah TIO OS?
9
A. 8.5 mmHg D. 10.2 mmHg
B. 8 mmHg E. 11.2 mmHg
C. 12.2 mmHg

51. Apa kelemahan potensial dari tonometer nonkontak dalam
pengukuran IOP?
A) Tidak akurat pada mata dengan bekas luka kornea atau
edema
B) Memerlukan anestesi topikal
C) Memerlukan baterai untuk menggunakan alat
D) Probe hanya sekali pakai
E) Tidak dapat digunakan pada anak
10

52. Terima Kasih