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M. Khurana and V. H. Albal
a
Fig. 23.15 (a, b, c) UBM images of the eyes of a patient post vitrectomy for non-resolving vitreous hemorrhage, show-
ing brovascular proliferation at the sclerotomy sites (arrows)
23.8 Intraocular Tumors
b
mass shows progressive enlargement on serial
biometry [16].
c
23.8.1 Iris andCiliary Body Cysts
Multiple ciliary body cysts can be seen in radial
and transverse scans on UBM. They have a
hyperechoic wall and an anechoic center
(Fig. 23.16). Inammatory lesions of the uveal
tract may present as a mass (Fig.23.16).
23.8.2 Uveal Mass Lesions
Uveal melanoma: A high correlation has been
reported between UBM [24] and histopathological features of anterior uveal melanomas.
The extent of the tumor can be defined, which
helps in planning the management (Fig.23.17).
UBM helps differentiate suspected iris melanomas from neuroepithelial cysts, traumatic
cysts, and vascular malformations. A peripheral neuroepithelial cyst shows a hyperechoic
thin wall with an anechoic center. An iris melanoma appears as a solid irregular iris mass
with variable internal reflectivity due to differences in vascularity. Distortion of surrounding structures is usually present. The posterior
iris plane may show a convexity. Invasion of
the iris root is a risk factor for metastasis. The
23.8.3 Ciliary Body Melanoma
It appears as an oval-shaped mass centered on the
ciliary body (Fig. 23.17). It is primarily solid
with low to medium internal reectivity although
some cavitation may be seen. The area of inva-
sion of adjacent tissues appears to have reduced
reectivity compared to the surrounding ciliary
body or iris [16].
23.8.4 Retinoblastoma
UBM helps in evaluating the anterior extents of
retinoblastomas [25]. High-resolution imaging of
the anterior retina, ciliary body, and the angle of
the anterior chamber of the eye can be done to
assess the extent of involvement and tumor exten-
sion beyond the retina (Fig. 23.18).
Retinoblastomas have reectivity similar to those
of the ciliary body. A ne line of high reectivity
may help in identication. The anterior vitreous
face, which is usually challenging to image, may
be imaged if outlined with tumor or inamma-
tory cells (Fig.23.18).
bc
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a
c
283
b
d
e
Fig. 23.16 Top left (a): a slit lamp photograph showing
an iris cyst. Top right (b): a UBM of the iris cyst, measuring about 4.2mm in diameter, with a hypoechoic lumen.
Middle left (c): a UBM transverse scan image showing
multiple ciliary body cysts. Middle right (d): a longitudi-
f
nal UBM image showing a large iridociliary cyst causing
secondary angle closure. Bottom left (e): radial; and bot-
tom right (f): transverse scan UBM images of an eye of a
patient with intermediate uveitis with an inammatory
ciliary body mass
a
Fig. 23.17 Left (a): A slit lamp photograph of an eye with an iris mass (arrow). Middle (b) and right (c): UBM images
showing the mass as a hyperechoic iridociliary lesion suspected as a melanoma
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M. Khurana and V. H. Albal
a
Fig. 23.18 Top: UBM images of an eye of a child with
retinoblastoma showing a ciliary body mass. The other
eye had undergone enucleation. Left (a): a radial scan, and
right (b): transverse scans. Bottom left (c): a wide-eld
fundus photograph of an eye with retinoblastoma (under
23.9 Conclusion
b
treatment) showing the tumor mass and inferior vitreous
seeds. Bottom right (d): a UBM image of the eye with
retinoblastoma showing vitreous seeds at the 6 o’clock
position (arrow)
References
UBM is a vital non-invasive modality for imaging the anterior segment, with its main strength
being the ability to visualize structures behind
the iris. It provides high-resolution images of the
anterior segment even in the presence of corneal
opacity. It is an important tool in understanding
the ocular anatomy, its pathophysiologies and in
planning the management of many conditions
like glaucoma, uveitis, cyclodialysis clefts, specic types of trauma, pediatric ocular diseases,
and anterior segment tumors. UBM is an important tool in our armamentarium for patient
management.
1. Pavlin CJ, Harasiewicz K, Foster FS. Ultrasound
biomicroscopy of anterior segment structures in
normal and glaucomatous eyes. Am J Ophthalmol.
1992;113:381–9.
2. Ishikawa H, Schuman JS.Anterior segment imaging:
ultrasound biomicroscopy. Ophthalmol Clin N Am.
2004;17:7–20.
3. Nolan W.Anterior segment imaging: ultrasound biomicroscopy and anterior segment optical coherence
tomography. Curr Opin Ophthalmol. 2008;19:115–21.
4. Allingham RR, Damji KF, Freedman S, etal. Shields
textbook of glaucoma. 6th ed. Lippincott: William
and Wilkins, Wolters Kluwer; 2011.
5. Byrne SF, Green RL.Ultrasound of the eye and orbit.
2nd ed. Jaypee Brothers Medical Publishers (P) Ltd;
2010.
23 Ultrasound Biomicroscopy
https://t.me/med1917
285
6. Pavlin CJ, Foster FS. Ultrasound biomicroscopy in glaucoma. Acta Ophthalmol Suppl.
1992;70(S204):7–9.
7. CASIA2 Cornea/Anterior segment Optical Coherence
Tomography Brochure, Tomey.
8. Marmor MF, Wickramasinghe HK, Lemons
RA. Acoustic microscopy of the human retina and
pigment epithelium. Invest Ophthalmol Vis Sci.
1977;16:660–6.
9. Ye SG, Harasiewicz KA, Pavlin CJ, Foster
FS.Ultrasound characterization of normal ocular tissue in the frequency range from 50MHz to 100MHz.
IEEE Trans Ultrason Ferroelectr Freq Control.
1995;42(1):8–14.
10. Sadaka A, Prager T, Beaver H, Malik A. A novel
use of ultrasound biomicroscopy. Eye (Lond).
2018;32(2):474–5.
11. Pavlin CJ, McWhae JA, McGowan HD, Foster
FS. Ultrasound biomicroscopy of anterior segment
tumors. Ophthalmology. 1992;99:1220–8.
12. McWhae JA, Crichton ACS, Rinke M. Ultrasound
biomicroscopy for the assessment of zonules after
ocular trauma. Ophthalmology. 2003;110:1340–3.
13. Ozdal MP, Mansour M, Deschênes J.Ultrasound biomicroscopic evaluation of the traumatized eyes. Eye
(Lond). 2003;17:467–72.
14. Marchini G, Pagliarusco A, Toscano A, et al.
Ultrasound biomicroscopic and conventional ultrasonographic study of ocular dimensions in primary angle-closure glaucoma. Ophthalmology.
1998;105(11):2091–8.
15. Barkana Y, Dorairaj SK, Gerber Y, et al. Agreement
between gonioscopy and ultrasound biomicroscopy in detecting iridotrabecular apposition. Arch
Ophthalmol. 2007;125:1331–5.
16. Narayanaswamy A, Vijaya L, Shantha B, et al.
Anterior chamber angle assessment using gonioscopy
and ultrasound biomicroscopy. Jpn J Ophthalmol.
2004;48:44–9.
17. Kumar RS, Baskaran M, Chew PT, et al. Prevalence
of plateau iris in primary angle closure suspects an
ultrasound biomicroscopy study. Ophthalmology.
2008;115(3):430–4.
18. Marigo FA, Esaki K, Finger PT, et al. Differential
diagnosis of anterior segment cysts by ultrasound biomicroscopy. Ophthalmology. 1999;106:2131–5.
19. Potash SD, Tello C, Liebmann J, Ritch R.Ultrasound
biomicroscopy in pigment dispersion syndrome.
Ophthalmology. 1994;101:332–9.
20. Alexander JL, Wei L, Palmer J, et al. A systematic
review of ultrasound biomicroscopy use in pediatric
ophthalmology. Eye. 2021;35:265–76.
21. Pavlin CJ, Ritch R, Foster FS.Ultrasound biomicroscopy in plateau iris syndrome. Am J Ophthalmol.
1992;113(4):390–5.
22. Yamamoto T, Sakuma T, Kitakawa Y. An ultrasound biomicroscopic study of ltering blebs after
mitomycin C trabeculectomy. Ophthalmology.
1995;102:1770–6.
23. Bhende M, Agraharam SG, Gopal L, etal. Ultrasound
biomicroscopy of sclerotomy sites after pars plana
vitrectomy for diabetic vitreous hemorrhage.
Ophthalmology. 2000;107:1729–36.
24. Conway RM, Chew T, Golchet P, et al. Ultrasound
biomicroscopy: role in diagnosis and management in
130 consecutive patients evaluated for anterior segment tumours. Br J Ophthalmol. 2005;89:950–5.
25. Vasquez LM, Giuliari GP, Halliday W, et al.
Ultrasound biomicroscopy in the management of retinoblastoma. Eye (Lond). 2011;25:141–7.
Ophthalmic Ultrasound
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SuganeswariGanesan , SashwanthiMohan ,
DebaratiDasgupta , andMunaBhende
24
Ocular ultrasonography was rst introduced in the
1950s by Mundt and Hughes. They described the
A-scan. Baum and Greenwood described the
B-scan in 1958, and Purnell and Coleman further
improved it [1–4]. Standardization was done in
the 1960s by Ossoinig, and other modications
such as immersion, contact B-scan, and anterior
segment imaging were introduced two to three
decades later [5, 6].
24.1 Physics
B-scan ultrasound uses high-frequency sound
waves to generate a two-dimensional topographic
image of the eye [7]. It uses a pulse-echo system
that generates an oscillatory signal transmitted to
the piezoelectric crystal in the ultrasound probe.
The piezoelectric crystal then generates an ultrasonic sound wave of high-frequency (8–10MHz)
projected onto the ocular tissue. The reected
echo is then collected by the transducer and
transmitted to the receiver, which amplies the
S. Ganesan (*) · M. Bhende
Medical Research Foundation, Sankara Nethralaya,
Chennai, India
e-mail: drgsi@snmail.org; drmuna@snmail.org
D. Dasgupta
Greater Lions Eye Hospital, Siliguri, India
S. Mohan
Medcare Eye Centre, Dubai and Rajan Eye Care
Hospital, Chennai, India
echoes and displays a 2D image of the eye called
an echogram. Several technical terms are used to
describe B-scans (Table24.1).
Table 24.1 Important B-scan terms
Term Denition
Echoes Produced at the junction of two
media with different acoustic
impedance
Acoustic
impedance
Angle of
incidence
Resolution Ability to distinguish between
Amplication This occurs before the reected
Absorption Sound wave is absorbed through
Gain Procedure of increasing or
Time gain
compensation
Difference in the strength of the
returning echoes between two
tissues with different acoustic
interfaces
Angle at which the sound strikes
an interface: the more
perpendicular the beam, the
stronger the returning echo will
be
two different echoes
sound beam is displayed, which
can be linear, logarithmic, or S
curve
mediums which it passes
through; the denser the medium,
the more the absorption
decreasing the amplitude of
echoes; higher gain can detect
weaker echoes
Technique used to enhance
returning echoes from deeper
structures by decreasing the ones
from structures closer to the
surface
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024
T. Das, P. Satgunam (eds.), Ophthalmic Diagnostics, https://doi.org/10.1007/978-981-97-0138-4_24
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24.2 Technique
Ultrasound is usually performed in the supine or
reclining position. The sitting position is utilized for gas or oil-lled eyes and to look for
shifting uid in exudative retinal detachments.
The ultrasound probe is either placed over
closed eyelids or directly placed over the conjunctiva or cornea with a coupling solution,
which reduces sound attenuation by air.
Documentation should be done with both stationary and dynamic images.
24.2.1 Probe Positions
The ultrasound probe has a marking. The marking denotes the upper part of the scan.
Depending on how the probe is oriented, there
are three different positions [7]:
1. Axial: This passes through the center of the
lens and optic nerve.
2. Transverse: This gives the lateral extent of the
lesion and covers the 6-clock hour.
3. Longitudinal: This covers the anteroposterior
extent of the lesion and covers the 1-clock
hour.
24.2.2.2 Transverse Scan
In transverse scans, the eye is directed towards
the area of interest. The probe is parallel to the
limbus on the opposite side. The probe marker is
conventionally directed nasally for examining
superior and inferior quadrants and superiorly for
examining temporal and nasal quadrants.
Transverse scans measure the lateral extent of a
lesion and cover the 6-clock hour in one scan.
24.2.2.3 Longitudinal Scans
In longitudinal scans, the eye is directed towards
the area of interest, with the probe perpendicular
to the limbus on the opposite side. The probe
marker is perpendicular to the limbus towards the
meridian of interest. Longitudinal scans measure
the anteroposterior extent of a lesion and cover
the 1-clock hour.
24.2.3 Limbus toFornix Approach
To examine the entire retina from the posterior
part to the anterior part, the limbus to fornix
approach is used, where the former position
shows the posterior pole and the latter shows the
anterior portion of the retina.
24.2.2 Performing theScans
24.2.2.1 Axial Scan
An axial scan is performed with the eye in the
primary position and the probe centered on the
cornea. Axial scans can be vertical, horizontal, or
oblique. For vertical axial scans, the probe marker
is directed superiorly; for horizontal axial scans,
the probe marker is directly nasally; for oblique
axial scans, the probe marker is directed towards
the upper of the two meridians scanned. In the
vertical axial scan, the retina is seen above, the
optic disc is seen below, and the macula is not
visualized. Axial length is measured in the horizontal axial scan, where the macula will be below
the optic disc when the probe marker is directed
nasally.
24.2.4 Special Examination
Techniques
The topographic technique helps determine the
location, shape, and extent of a lesion. The quantitative technique shows the reectivity, internal
structure, and sound attenuation of a lesion.
Kinetic echography shows the motility, i.e., aftermovement; vascularity, i.e., fast spontaneous
motion; and convection motion, i.e., slow spontaneous motion.
24.3 Indications
Ultrasound B-scan is indicated in both clear and
opaque ocular media. Table24.2 gives the list of
clinical indications for ophthalmic ultrasound.
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Table 24.2 Indications of ultrasound B-scan
Clear ocular media Opaque ocular media Others
Iris and ciliary body
tumors
Retinal detachment Pupillary membrane
Choroidal
detachment (serous
vs. hemorrhagic)
Intraocular tumors Dense cataracts
Optic disc
anomalies
Intraocular foreign
body
Posterior scleritis Vitritis
Corneal opacity Ocular
trauma
Hyphema/hypopyon
Non-dilating pupils
Vitreous
hemorrhage
Retinal detachment
Intraocular foreign
body
24.4 Clinical Applications
24.4.1 Anatomy ofaNormal
Ultrasound (Fig.24.1)
• Lens: An oval, highly reective structure with
intralesional echoes based on the degree of
lens opacity. It is best seen with the standoff or
immersion technique.
• Vitreous: Usually echo-lucent but can have
low reective echoes with age, secondary to
syneresis.
• Retina, choroid, sclera: Seen as a single highly
reective structure which can only be differentiated when there is a pathology such as
retinal detachment, choroidal detachment, and
posterior scleritis.
• Optic nerve head: Wedge-shaped echo-lucent
area in the retrobulbar area in the axial scan. It
is best visualized in the vertical transverse
scan.
• Extraocular muscles: Low reective fusiform
structures within the orbit.
bright homogenous, densely packed dot echoes
with medium to high reectivity with a clear
zone between the echoes and the retina [8].
24.4.3 Vitreous Hemorrhage
(Fig.24.1)
Vitreous hemorrhage (VH) is the extravasation of
blood into the vitreous cavity secondary to conditions like proliferative diabetic retinopathy, retinal
vein occlusion, trauma, retinal breaks, etc. On
ultrasound, fresh VH appears as multiple mobile
dot echoes and short lines of low reectivity in the
vitreous on the A-scan. When the hemorrhage gets
organized, it appears as membranous echoes with
higher reectivity on the A-scan. In dense VH,
there is an increase in the echoes with high reectivity. Ultrasound is a useful tool for diagnosis,
prognosis, and monitoring in cases of VH [9, 10].
24.4.4 Posterior Vitreous
Detachment (Fig.24.1)
Posterior vitreous detachment (PVD) is the
detachment of the posterior hyaloid from the neurosensory retina, which can be complete or
incomplete. On ultrasound, it appears as a membranous echo with low to moderate reectivity on
the A-scan. An incomplete PVD is attached to the
optic nerve head, whereas a complete PVD is
freely mobile and not attached to the optic nerve
head; a PVD usually has good after-movements
on kinetic scans. Hemorrhagic PVD has a thicker
membranous echo with a higher reectivity on
the A-scan. To differentiate PVD from retinal
detachment (RD), different portions of the PVD
should be examined to look for decreased reectivity, which is suggestive of the vitreous membrane [7].
24.4.2 Asteroid Hyalosis (Fig.24.1)
Asteroid hyalosis (AH) is a degenerative condition where calcium-lipid complexes are suspended throughout the collagen brils of the
vitreous. On ultrasound, they appear as multiple
24.4.5 Retinal Detachment (Fig.24.2)
Rhegmatogenous RD is a separation of the neurosensory retina from the retinal pigment epithelium secondary to a full-thickness retinal
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a
c
b
d
Fig. 24.1 Top left: Normal USG. Lens echo (a) seen
with the anechoic vitreous cavity (b). Retina attached with
normal retinal-choroidal-scleral (RCS) complex (c); the
optic nerve head shadow appears normal (d). Top right:
In asteroid hyalosis, the vitreous shows plenty of moderate to high reective dot echoes with clear spaces between
these echoes and the RCS complex. Bottom left: In vitreous hemorrhage, the vitreous cavity shows a moderate
break. It is the most common type of RD.On
ultrasound, it appears as a bright, continuous
membrane with close to 100% reectivity,
higher than ocular coats on the A-scan. On the
B-scan, it is attached to the optic nerve head. It
has poor after- movements on kinetic scans and
is always less mobile than the vitreous membranes [11].
number of low reective dot echoes and moderate reective membranous echoes attached to the optic nerve head
(arrow). A low reective membrane echo attached to the
optic nerve head suggests incomplete posterior vitreous
detachment. Bottom right: A low reective membrane
echo not attached to the optic nerve head (arrow) suggests
complete posterior vitreous detachment
24.4.6 Tractional RD (Fig.24.2)
Tractional RD is detachment of the neurosensory
retina secondary to traction in retinal vascular
diseases such as proliferative diabetic retinopathy, retinal vein occlusions, retinopathy of prematurity, and trauma. On ultrasound, it appears
as a concave membrane with high reectivity on
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Fig. 24.2 Top left: Total retinal detachment. Red Arrow:
A highly reective membrane is attached to the optic nerve
head to the periphery with subretinal echoes; Yellow Arrow:
Subtle retinochoroidal sloping is noted behind the RD. Top
right: Chronic RD.A highly reective membrane echo is
attached from the optic nerve head to the periphery, with
the A-scan with varying extents of vitreous adhesions. It can have a tented or table-top conguration which does not extend to the ora serrata with
a vitreous band connected to the anterior surface.
They have lesser mobility than rhegmatogenous
RDs because of traction on the retina [12].
24.4.7 Exudative RD (Fig.24.3)
Exudative RD is an accumulation of fluid in
the subretinal space without retinal breaks and
underlying cystic changes (arrow) and subretinal echoes are
present. Bottom left: Giant retinal tear with RD. Highly
reective convoluted membranous double linear echo
(arrow). Bottom right: Tractional RD.A partially detached
posterior hyaloid is noted with multiple attachments causing focal tractions at numerous points (arrow)
occurs secondary to inflammations, infections, neoplasms, etc. On ultrasound, it appears
as a bullous membranous echo with high
reflectivity on the A-scan and a smooth surface without rugae in the B-scan. It has a characteristic “shifting fluid” appearance that can
be noted by changing the patient’s head position, which changes the configuration of the
exudative detachment. Depending on the
underlying condition, associated findings can
include retinochoroidal thickening, choroidal
masses, etc.
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Fig. 24.3 Top row: Exudative retinal detachment. A
moderately high reective membrane echo (arrow) is
noted located only inferiorly initially (left) but involving
the posterior pole in the supine position, suggestive of
24.4.8 Choroidal Detachment (CD)
(Fig.24.3)
A CD is dened as the detachment of the choroid
from the sclera due to the accumulation of uid or
hemorrhage in the suprachoroidal space. It is
bound by uveoscleral solid attachments. On ultrasound, it appears as a smooth, dome-shaped membrane with a double highly reective spike on the
A-scan, called the “M spike.” The “M spike”
refers to the echoes from the choroid and retina.
shifting uid (right). Bottom row: Choroidal detachment.
Total retinal detachment with dome-shaped elevation and
hypo-echoic space beneath it suggests serous choroidal
detachment (arrow)
The CD is not attached to the optic nerve head
and has no after-movements on kinetic scans.
When CDs touch each other, it is called “kissing
choroidals.” Serous CDs have an echo-lucent
space behind the membrane, and hemorrhagic
CDs have multiple mild to moderate reective dot
echoes behind the membrane. Shallow peripheral
CDs appear at or concave and not dome-shaped
[13]. Ultrasound helps monitor clot lysis in cases
of hemorrhagic CDs and helps in deciding the
time and location of drainage.
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