# Vitreous Hemorrhage Ocular Ultrasound Diagnosis

- Link: https://sifsof.com/clinical-apps/vitreous-hemorrhage-ocular-ultrasound-diagnosis/
- Published: 2021-09-29T14:16:10+00:00
- Author: Developer

Vitreous hemorrhage (VH) is an important ophthalmic condition that may cause an 
abrupt decrease in visual acuity (VA) and it often occurs as a complication of an
underlying disease. VH has an annual incidence of 7 to 15.4 cases per 100,000 persons,
depending on the population studied. Some of the main causes of VH may be proliferative
diabetic retinopathy (PDR), retinal vein occlusions (RVOs), ocular trauma, posterior
vitreous detachment with or without a retinal tear, etc.

During the acute hemorrhagic event, blood passes through holes or apertures in the
posterior hyaloid into the vitreous cortex, needing from weeks to months to clear
from this location. A vitreous hemorrhage may result from proliferative retinopathy,
the condition in which new, abnormal blood vessels grow on the surface of the retina.
This is referred to as neovascularization. When not treated, these new blood vessels
may continue to grow and spread through the vitreous onto the pupil area. This can
increase ocular pressure (pressure within the eye) that presses on the optic nerve.
Damage to the optic nerve is irreparable and can lead to vision loss. Bleeding from
a vitreous hemorrhage can also cause scar tissue to form near the back of the eye.
This can pull the retina away from the back lining of the eye, requiring additional
treatment to keep the retina from detaching and permanently damaging vision.

Doctors will examine the patient’s eyes as well as review their medical history 
to determine the cause of the hemorrhage and recommend the appropriate treatment.
To confirm the diagnosis, a series of diagnostic tests may be performed such as:

 * Gonioscopy
 * Dilated eye examination
 * IOP
 * Indirect ophthalmoscopy
 * Slit-lamp examination
 * B-scan

[ Nussenblatt´s standardization](https://www.researchgate.net/publication/278199826_Standardization_of_uveitis_nomenclature_for_reporting_clinical_data_Results_of_the_First_International_WorkshopJabs_DA_Nussenblatt_RB_Rosenbaum_JT_Standardization_of_Uveitis_Nomenclature_SUN_Working_G)
for vitreous opacities could be used as a system to clinically grade the opacities.
In this scale, the clinical view through [indirect ophthalmoscopy ](https://eyewiki.aao.org/Binocular_Indirect_Ophthalmoscopy)
of the fundus is compared to a set of standard photographs with different degrees
of vitreous haze. This scale is a straightforward way to categorize a VH, allowing
the physician in day-to-day clinical practice to remember roughly the structures
that need to be visible, in order to grade the hemorrhage without looking constantly
at the reference images.

Although Nussenblatt’s grading scale has become the standard for more than 30 years,
several problems with this system could be considered. First, it may have moderate
interobserver agreement, as reported by Hornbeak et al. Secondly, as categorical
variables, patients that fall in-between categories could yield to the subjective
interpretation of each individual examiner and, therefore, may result in low agreement
between observers; third, the scale does not allow an adequate measurement of sporadic
or interventional improvement, regardless of the vitreous opacity. Therefore, a 
more objective and reproducible grading method could prove useful.

Quantification of vitreous hemorrhages (VH) termed minimum image gain (MIG) can 
be determined through ultrasound. Since its introduction into the ophthalmology 
field in 1956. Ocular ultrasound has become an invaluable tool that helps determine
diagnoses and treatment decisions. All ultrasound systems allow adjustments in the
amplification of the echo signals, in other words, the strength of the ultrasound
beam. Changing the amplitude will modify the gain or sensitivity setting of the 
system. Gain is measured in a logarithmic scale in decibels (dB), which represent
relative units of ultrasound intensity from the returning echo. Higher gain levels
allow greater ability to display weaker echoes, such as vitreous opacities, whereas
lower gain levels allow only stronger echoes, for example the sclera, to be displayed.
Therefore, gain levels could prove useful as a measuring scale to determine the 
lowest signal intensity obtained from a specific structure (in the present case,
the vitreous humor and VH).

The density of a specific tissue scanned by an ultrasound could be determined by
knowing the acoustic impedance and the speed of sound in that tissue, which would
imply having different software adaptations in the echography system. A more simple
solution could be to modify the amplitude of the echo signals. Most (if not all)
ocular ultrasound systems have the possibility to alter the gain or sensitivity 
to visualize a structure. With a lower gain, the amplitude of the ultrasound wave
will not be strong enough and will attenuate as it goes through the tissue (in this
case, the vitreous cavity). Higher sensitivity decreases attenuation, allowing the
visualization of minute details. Decreasing the gain until no vitreous humor (or
VH) is visualized (minimum gain) would mean that the specific density of the tissue(
vitreous and hemorrhage) would be sufficient enough to attenuate the signal at that
specific dB. VHs were demonstrated to have lower MIG measurements (52.8 dB) when
compared with controls (77.97 dB). Because of the hemorrhage, the density of the
vitreous is higher, and therefore, MIG is lower.

 As per protocol: With the patient at dorsal decubitus position, a 10 MHz, B-scan
ultrasound probe (with a depth of exploration of 20 to 60 mm, focus of 21 to 25 
mm, axial resolution of 150 µm, and lateral resolution of 300 µm) is used to evaluate
the temporal quadrant of the globe. A longitudinal image is obtained where the optic
nerve head, macula, peripheral retina, and external rectus muscle could be visualized.
Therefore, the 9 o’clock meridian is analyzed for right eyes and 3 o’clock for left
eyes.

Based on the ocular ultrasound screening protocols for Vitreous hemorrhage we highly
recommend the Ophthalmic Ultrasound Scanner [SIFULTRAS-8.1](https://sifsof.com/product/ophthalmic-digital-ultrasound-scanner-sifultras-8-1/).
This ultrasound enables operators to easily image the anterior and posterior segments
of the eye; providing important information not possible with clinical examination
alone. Equipped with B-scan at Frequency range : 10MHz/20MHz (optional) ,Magnetic
driven and noiseless, Real-Time magnification, 60 mm depth this device has proved
to be an excelent choice for diagnosing Vitreous hemorrhage. It enhance the part
of vitreous body and retina with a probe gain of 30dB-105dB perfectly suitable for
grading vitreous hemorrage. Furthermore the SIFULTRAS-8.1 is equipped withan A-scan
mode for anterior chamber depth, lens thickness, vitreous body length and total 
length measurements for cataract surgery to pick the right lense replacement and
for diagnosis of tummors.

This procedure should be performed by a qualified ophthalmologist*

Reference: [Vitreous Hemorrhage: Diagnosis and Treatment](https://www.aao.org/eyenet/article/vitreous-hemorrhage-diagnosis-treatment-2)

[Scale for Photographic Grading of Vitreous Haze in Uveitis](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3220938/)

 * ![Ophthalmic Ultrasound Scanner SIFULTRAS-8.1 main pic](https://sifsof.com/wp-
   content/uploads/2017/04/SIFULTRAS-8.1-Portable-Ophthalmic-Digital-Ultrasound-
   Scanner-300x300.jpg)
 * Ophthalmic Ultrasound Scanner SIFULTRAS-8.1
