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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_103_библиотеки_им_акад_М_И_Перельмана
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Fig. 23.2 A diagrammatic
representation of probe
position during UBM
scanning. The highlighted
yellow part shows the mark
on the probe (a) radial scan
(b) transverse scan
Table 23.2 Scan types in UBM
Type Technique Remark
Axial Probe is placed perpendicular to the corneal
surface over the pupil
– Horizontal scan: marker is oriented nasally
– Vertical scan: marker is oriented superiorly
Radial
(longitudinal)
Transverse Probe placed parallel to the limbus
Probe is placed perpendicular to the limbus at
each clock hour
– Central scan: over the cornea and iris
– Peripheral scan: over the limbus
Good for assessing
– anterior chamber depth
– orientation of displaced or tilted
It is the most common scan used in UBM
examinations.
Good for imaging the following:
– anterior chamber angle, identication
– anterior to posterior extent of mass
Ideal for the evaluation of:
– lateral extent of iris and ciliary body
– ciliary processes
M. Khurana and V. H. Albal
intraocular lenses
of the scleral spur, ciliary body
lesions of the iris and ciliary body
masses
ClearScan® is a single-use UBM probe tip
cover consisting of a ne acoustically invisible
lm that can be lled with water. It eliminates the
chances of ocular injury with the moving transducer and the need for a scleral shell [10]. This
allows the scan to be performed in a sitting or
reclining position.
To perform the examination, the probe is
placed directly over the ocular structures to be
imaged. The penetration of the ultrasound
through the skin is not as good as through the
conjunctiva, as the keratinized epithelium attenuates the ultrasound beam.
The cornea, iris, and crystalline lens can be
imaged in any plane. Radially orientated images
through the limbus provide a cross-sectional
view of the anterior chamber angle (Fig. 23.2,
Table 23.2). To image the conjunctiva, anterior
sclera, ciliary body, and ora, the patient is asked
to look 180° away from the clock hour of interest.
Images are brightest when the probe is perpendicular to the surface examined, and the reected
sound is returned directly to the transducer [1].
The top of the UBM display screen corresponds to the front of the transducer. A marker
along the probe’s side helps in the orientation of
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Fig. 23.3 Types of scans in UBM.Left (a): an axial scan. Middle (b): longitudinal (radial) scan showing the angle of
the anterior chamber. Right (c): transverse scan showing the ciliary processes
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transducer movement and the image formed. The
far left of the display screen corresponds to the
area toward the marker, and the far right of the
display screen corresponds to the area away from
the marker [4]. In the image, structures at the top
of the display screen are closest to the probe tip,
and those at the bottom are the farthest (Fig.23.2).
Measurements within the scanned area can be
carried out with the software provided with the
machine (Fig.23.3) [1].
23.5 Clinical Applications
ofUltrasound Biomicroscopy
UBM is useful in assessing the anterior segment,
with details of the anatomical structure, pathology, and pathophysiology of various ocular diseases. UBM is contraindicated in penetrating
ocular trauma. Here, we describe the clinical
application of UBM in diagnosing and managing
different ocular conditions.
23.5.1 Ocular Surface
UBM helps identify the extent of ocular surface
tumors [11], invasion of adjacent structures, and
the posterior limit. It is useful in imaging in the
presence of corneal opacities and pigmented
lesions (Figs.23.4 and 23.5).
23.5.2 Cornea
In UBM, the corneal epithelium has a smooth
reection; Bowman’s membrane and Descemet’s
membrane-endothelial layer are highly reective
lines with a hypoechoic stroma in between. UBM
helps in imaging corneal edema (microcystic and
stromal) and Descemet’s membrane detachment
in the presence of corneal haze or opacity. The
anterior segment status in eyes with corneal opacity can be assessed for any iridocorneal touch,
anterior synechiae, and iridolenticular contact
(Fig.23.6).
23.5.3 Sclera
UBM can be useful in imaging the sclera anterior
to the equator. In episcleritis, a localized hyperreective thickened area is seen in the episcleral
tissue with normal reectivity of the scleral
stroma. In scleritis, both episcleral and scleral
stroma appear hyperechoic.
23.5.4 Lens andZonules
1. Normal zonules appear as medium reective
lines extending from the ciliary processes to
the lens margin [9, 10]. UBM helps in identifying areas of zonular abnormalities.
Increased lenticular sphericity is seen in areas
of zonular abnormality. Direct signs of zonular abnormality include the absence of zonular
bers, increased zonular ber length, and the
presence of zonular remnants on the lens capsule. Ciliary body attening and increased
lens–ciliary body distance can also be seen
(Fig.23.7) [11].
2. Position of the intraocular lens: UBM can
detect the position of the posterior chamber
intraocular lens (IOL) in eyes with pseudophakic pigment dispersion and uveitis glau-
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a
b
cd
Fig. 23.4 (a) A diffuse slit lamp photograph of ocular
surface squamous neoplasia. It is seen as a mass lesion
extending from the cornea to the conjunctiva across the
limbus without any episcleral or scleral involvement. (b–
d) are UBM images of ocular surface neoplasia without
underlying corneal involvement
the posterior chamber IOL (Fig. 23.8) [4].
UBM can localize the haptic position in eyes
with UGH syndrome, where the haptics erode
the iris and ciliary process and cause uveitis,
glaucoma, and hyphema [4].
3. Microphakia and spherophakia: The equatorial and anterior-posterior diameter of the
crystalline lens can be determined with UBM
in eyes with microspherophakia and spherophakia (Fig.23.8).
4. Trauma to lens: Anterior and posterior cap-
sule status can be determined in traumatic
cataract. Position of the crystalline lens and
zonular status can be imaged [12, 13]
(Fig.23.8).
Fig. 23.5 A UBM image of a limbal dermoid. The lesion
is well-dened without any corneal involvement
coma hyphema (UGH) syndrome. A
single-piece square edge or plate-haptic IOL
placed in the ciliary sulcus can cause pigment
dispersion. UBM helps detect the position of
23.5.5 Glaucoma
UBM provides qualitative and quantitative
information regarding primary and secondary
glaucoma pathophysiology. It is useful in imag-
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Fig. 23.6 (a) A diffuse slit lamp photograph of an eye
with a failed graft following penetrating keratoplasty, secondary angle closure glaucoma, and Ahmed glaucoma
valve (AGV) implantation. (b) UBM image of the same
Fig. 23.7 A UBM image illustrating zonular dehiscence
(arrow) in an eye with blunt trauma and subluxation of a
cataractous crystalline lens. The rounding of the lens edge
is seen due to a lack of zonular support
ing the angle of the anterior chamber, iris and
lens conguration, and ciliary body, helping
diagnose and plan the management [1, 4, 6,
14–22].
23.5.5.1 Angle Closure Disease
UBM helps identify and understand the various
mechanisms of angle closure disease because it can
eye shows a patent AGV tube, which is not visible clinically. Iridocorneal adhesions [anterior synechiae] can also
be appreciated
image the ciliary body and lens. Identication of the
scleral spur as a landmark is important in assessing
the angle morphology. The various mechanisms of
angle closure are (Fig.23.9) as follows:
(a) Lens iris diaphragm conguration: A con-
vex iris conguration, shallow anterior
chamber, and iridotrabecular contact are
seen in angle closure disease due to a relative
pupillary block (Fig.23.9).
(b) Plateau iris conguration: An anteriorly
directed ciliary processes pushing the peripheral iris and causing iridotrabecular contact
is present (Fig.23.9) [1–4, 15]. The ciliary
sulcus is absent, the iris root is short or thick,
and a steep iris root from its point of insertion followed by a downward angulation is
present along with a at iris plane. The central anterior chamber depth is normal.
(c) Pseudoplateau iris with cysts of iris and
ciliary body epithelium: On UBM, these
multiple neuroepithelial cysts of the ciliary
body have a well-delineated wall without a
solid component. They push the peripheral
iris leading to iridotrabecular contact
(Fig.23.9) [1–4, 16].
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Fig. 23.8 Top left (a): an axial UBM image of a normal
pseudophakic eye showing a posterior chamber intraocular lens in the capsular bag. The haptic’s echo in the bag is
visible. Top right (b): a UBM image showing a posterior
chamber intraocular lens (IOL) with one haptic placed in
the ciliary sulcus (arrow). Middle left (c): a UBM image
of a pseudophakic eye showing an anteriorly tilted posterior chamber IOL touching the iris (arrow) with the formation of posterior synechiae. Middle right (d): an axial
b
d
UBM scan of an eye with microspherophakia and angle
closure disease. Bottom left (e): an axial UBM image of
an eye of a child with a traumatic cataract with a ruptured
anterior capsule. Bottom right (f): longitudinal UBM
images of the eye of a child with blunt trauma, corneal
scar, and secondary glaucoma taken during examination
under anesthesia. Posterior synechiae with iris bombe
were present. A ruptured anterior lens capsule with lens
matter in the anterior chamber was demonstrated (arrow)
(d) Phacomorphic glaucoma: An intumes-
cent cataract and an increased anteroposterior lens thickness result in a pupillary
block with subsequent angle closure
(Fig.23.9). It can also occur in eyes with
an anteriorly subluxated lens or zonular
low central and peripheral anterior chamber
depth (Fig.23.9) [1–4].
(f) Supraciliary effusions: In eyes with second-
ary angle closure due to a push mechanism,
UBM helps in identifying supraciliary effu-
sions which may not be clinically detectable.
laxity or loss, which can be imaged with
UBM.
(e) Aqueous misdirection syndrome: The
UBM shows an anterior rotation of ciliary
processes, iridotrabecular contact and shal-
23.5.5.2 Secondary Open-Angle
Glaucoma
UBM is useful in the following situations in secondary open-angle glaucoma
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a
c
Fig. 23.9 Top: left (a): structures of the anterior chamber
angle and anterior segment as seen on UBM.C= cornea,
S=sclera, SS=scleral spur (scleral spur is where the trabecular meshwork meets the ciliary body and scleral interface; a change in curvature is seen), LC=lens capsule,
CB=ciliary body, AC=anterior chamber, PC=posterior
chamber. Top right (b): a UBM image of a longitudinal
scan of an eye with primary angle closure glaucoma showing iridotrabecular contact (asterix) due to pupillary block
indicated by the bowing of the iris. Middle left (c): a UBM
image of a longitudinal scan of an eye with plateau iris
conguration showing iridotrabecular contact, absence of
a ciliary sulcus, and an anteriorly placed ciliary process.
b
d
Middle right (d): a UBM image of a longitudinal scan of
an eye with ciliary body cysts showing iridotrabecular contact, absence of a ciliary sulcus, and a ciliary body cyst.
Bottom left (e): a UBM image of a case of phacomorphic
glaucoma. The intumescent cataractous lens is pushing the
iris anteriorly, causing angle closure. An increase in the
lens thickness (anterior-posterior diameter) with iridolenticular contact and a shallow anterior chamber is present.
Bottom right (f): a UBM image of an axial scan in an eye
with aqueous misdirection (malignant glaucoma) showing
uniform shallowing of the anterior chamber and anteriorly
rotated ciliary processes due to a push mechanism in a
pseudophakic eye. The anterior chamber depth is 0.19mm
(a) Pigment dispersion syndrome (PDS) and
pigmentary glaucoma (PG): In eyes with PDS
and PG, a deep anterior chamber with posterior
bowing of the mid-peripheral iris, causing a
reverse pupillary block is seen (Fig.23.10). The
posterior insertion of the iris root and iris-zonular apposition are responsible for the pigment
dispersion from the posterior pigmented epithelium of the iris can be imaged [19].
(b) Angle recession: Deepening of the angle
recess and a tear of the ciliary processes
from the scleral spur can be detected
(Fig.23.10).
(c) Pseudoexfoliation (PXF): Zonular abnor-
mality and lens position can be imaged in
patients with PXF [14]. The PXF material
can be seen on the zonules and peripheral
lens capsule.
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Fig. 23.10 Top left (a): a slit lamp photograph of an eye
with pigment dispersion syndrome (PDS) showing a
Krukenberg’s spindle. Top right (b): a UBM axial image
of the eye with PDS showing posterior bowing of midperipheral iris. Bottom left (c): a UBM image of an eye
with PDS showing iridozonular contact. Bottom right (d):
a gonioscopic photograph showing angle recession in a
closed globe injury and angle recession glaucoma. Bottom
left (e): a UBM longitudinal angle scan in an eye with
blunt trauma demonstrating angle recession (arrow)
abc
Fig. 23.11 Left (a): a UBM image of an eye of a child
with uveitic glaucoma with buphthalmos. The UBM
image shows anterior synechiae with the iris plastered to
the cornea. Middle (b) and right (c) UBM images of an
(d) Childhood glaucoma: In childhood glau-
coma with corneal haze or opacity, UBM can
image the anterior segment (Fig. 23.11).
UBM is helpful in imaging eyes and under-
eye with anterior segment dysgenesis in a child with corneal opacity and congenital glaucoma; the iris is seen to
be adherent to the cornea
ciliary body can be performed (Fig. 23.12,
Table23.3). Pavlin described certain parameters, taking the scleral spur as the reference
point [21].
standing the pathophysiology of primary and
secondary childhood glaucoma [20]. The
lens status can also be assessed in eyes with
spherophakia (Fig.23.11).
23.5.5.2.1 Quantitative Measurements
Quantitative measurements of the angle of the
anterior chamber, anterior chamber, lens, and
23.5.5.2.2 Glaucoma Surgery
(a) Glaucoma drainage devices (GDDs): UBM
can localize the position of tube of GDDs in
the anterior chamber (Fig.23.13), ciliary sulcus, or vitreous cavity (Fig.23.13). It can also
help assess tube patency and identify the
cause of the blockage, such as by the iris or
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Fig. 23.12 Left: UBM scans illustrating the quantitative
measurements of the anterior chamber angle described in
Table23.3. Right: UBM scans illustrating the quantitative
Table 23.3 Quantitative measurements of the anterior chamber using UBM
Quantitative parameters Description
Angle opening distance (AOD)
– 500
– 750
Trabecular iris angle (TIA) The apex of the angle is in the angle recess: the arms of the angle pass
Trabecular ciliary process distance
(TCPD)
Iris thickness
– ID1
– ID2
– ID3
Iris ciliary process distance (ICPD) Measured distance between iris and ciliary body (carried forward along the
Iris zonular distance (IZD) Measured distance between iris and lens zonules (carried forward along
Iris-lens contact distance (ICLD) Measured distance of iridolenticular contact
Iris-lens angle Angle formed by the anterior lens surface with the iris at the pupillary margin
Measured perpendicular distance between the iris and the trabecular
meshwork at a point either 500 μm or 750 μm anterior to the scleral spur
through a point on the trabecular meshwork at 500μm from the scleral
spur and the point on the iris perpendicularly opposite
Measured distance between the ciliary process and the trabecular
meshwork at a point 500 μm anterior to the scleral spur on a line
perpendicular through the iris
Measured thickness of the iris:
– 500μm anterior to scleral spur
– 2mm from iris root
– at pupillary edge
line of TCPD)
the line of TCPD)
measurements of the anterior chamber (lens thickness and
anterior chamber depth) and the lens vault
emulsied silicon oil (Fig.23.10). UBM can
help detect a tube-corneal touch in eyes with
corneal decompensation (Figs. 23.6 and
23.13).
(b) Trabeculectomy: UBM can be used to
assess the patency of trabeculectomy
stoma and bleb morphology (Fig. 23.13)
[22]. Cyclodialysis cleft can be detected in
cases of postoperative hypotony
(Fig.23.13).
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Fig. 23.13 Top left (a): a UBM image of an eye follow-
ing Ahmed glaucoma valve implantation with the tube in
the anterior chamber and showing the tube touching the
corneal endothelium. Top right (b): a UBM image of an
eye with silicone oil-induced glaucoma with Ahmed
glaucoma valve implantation (pars plana tube insertion)
with emulsied silicon oil bubbles blocking the tube
23.6 Uveitis
UBM helps detect the pathophysiology of glaucoma in eyes with uveitic glaucoma, for example,
pupillary block glaucoma (Fig. 23.14) and sec-
b
lumen (arrow). Bottom left (c): a UBM image of an eye
with an encapsulated bleb following trabeculectomy. A
patent trabeculectomy stoma (green arrow) and periph-
eral iridectomy can be seen (red arrow). A large bleb
with a thick wall (asterisk) is present. Bottom right (d):
a UBM image showing a cyclodialysis cleft with supra-
ciliary effusion
ondary angle closure due to non-pupillary block
mechanisms like uveal effusions. It can image the
status of the ciliary processes (Fig.23.14), supra-
ciliary effusions, and cyclitic membranes in eyes
with hypotony (Fig.23.14).
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b
d
e
Fig. 23.14 Top left (a): a diffuse slit lamp photograph
of an eye with panuveitis and secondary angle closure
with hypotony. Top right (b): a UBM transverse section
image of the same eye showing thin, sparse, and short
ciliary processes with supraciliary effusion. Middle left
(c): a UBM image (axial scan) in a pseudophakic eye
with anterior uveitis and posterior synechiae showing
23.7 Vitreo Retinal Surgery
UBM is useful in identifying brovascular proliferation (Fig.23.15) and complications at the
f
iris bombe and secondary angle closure. Middle right
(d): a UBM image showing a supraciliary effusion.
Bottom left (e): an axial UBM image of a patient with
chronic uveitis showing cyclitic membranes (arrow) and
peripheral anterior synechiae. Bottom right (f): a trans-
verse UBM image of a case of chronic uveitis with
cyclitic membranes
sclerotomy sites following pars plana vitrec-
tomy [23].
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