Ultrasound biomicroscopy (UBM) is the investigation of choice in which of the following clinical situations?
- A Evaluating a ciliary body tumor obscured by an opaque peripheral cornea ✓
- B Measuring axial length prior to cataract surgery
- C Detecting subretinal fluid in an eye with media opacity
- D Quantifying macular edema before intravitreal therapy
Correct answer: A. Evaluating a ciliary body tumor obscured by an opaque peripheral cornea
Explanation
UBM uses frequencies of 35 to 50 MHz, giving high resolution but shallow penetration of only about 4 to 5 mm, so it images structures from the corneal endothelium to the pars plana, including the ciliary body, iridocorneal angle and zonules. It is therefore ideal for ciliary body tumors, plateau iris and angle-closure assessment. Posterior segment problems such as subretinal fluid and macular edema need standard 10 MHz A-scan or OCT, and axial length needs biometry.
Reference: Kanski's Clinical Ophthalmology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.