B-Scan Ultrasonography for Right Eye Evaluation
When posterior segment visualization is limited in the right eye, B-scan ultrasonography is the appropriate next step to evaluate for retinal detachment, vitreous hemorrhage, intraocular masses, posterior staphyloma, and other posterior segment pathology. 1, 2
Primary Indication
B-scan ultrasonography is specifically indicated when media opacity prevents adequate fundoscopic examination of the posterior segment 1, 2. This includes:
- Dense cataract obscuring the view 1, 3
- Vitreous hemorrhage preventing retinal visualization 2, 4, 3
- Corneal opacity or other anterior segment pathology limiting view 4
- Any media opacity precluding adequate ophthalmoscopy 2, 5
What B-Scan Can Detect
The examination should specifically search for 1, 2:
- Retinal detachment - the most common abnormality found (39% in screening studies) 3, 6
- Vitreous hemorrhage or opacities - second most common finding (31%) 3, 6
- Intraocular masses (melanoma, metastases, retinoblastoma) 1, 7
- Posterior staphyloma 1, 3
- Retinal tears 2, 5
- Intraocular foreign bodies 3, 6
- Globe size abnormalities 6
Critical Performance Considerations
Dynamic examination is essential - static images alone are insufficient to distinguish between vitreous detachment, retinal detachment, and choroidal detachment 4. The real-time assessment allows differentiation of these conditions that would otherwise be impossible to separate 4.
The sensitivity of B-scan for detecting retinal pathology in fundus-obscuring vitreous hemorrhage varies considerably (44%-100%), so clinical correlation remains essential 2.
Follow-Up Protocol When B-Scan is Negative
If vitreous hemorrhage obscures all retinal details and B-scan ultrasonography is negative, weekly examinations are required until the hemorrhage resolves sufficiently to perform thorough indirect ophthalmoscopy with scleral depression 2, 5.
When a retinal tear is suspected despite negative initial B-scan, repeat ultrasonographic examination should be performed within 1-2 weeks 2.
Complementary Imaging
While B-scan addresses the posterior segment when media is opaque, consider these additional modalities when the view is adequate 1:
- OCT for macular architecture, epiretinal membranes, and detecting paracentral acute middle maculopathy (PAMM) - the earliest sign of retinal artery occlusion 1, 2
- Fluorescein angiography when posterior pole circulation abnormalities are suspected 1
- Anterior segment OCT or ultrasound biomicroscopy for complex anterior pathology evaluation 1
Common Pitfall
Do not delay B-scan ultrasonography waiting for media to clear spontaneously, as this risks missing time-sensitive pathology like retinal detachment that requires urgent surgical intervention 2, 3.