Background: The purpose of this observational case series study was to investigate the role of 25 MHz ultrasound biomicroscopy (UBM) in detecting subluxated lenses and compare it with 50 MHz UBM.
Methods: 45 patients (49 eyes) with suspected subluxation of the lens and 20 normal volunteers (40 eyes) were included. Different cross-sectional images of the lens position were captured in axial and longitudinal scanning modes using 25 and 50 MHz UBM. The main outcome measurements included the linear distance between the lens equator and ciliary process, the difference value (D-value) between the same cross section of the above bilateral linear distance in the normal and the subluxated subjects, the diagnostic accuracy, and the testing times obtained with 25 and 50 MHz UBM.
Results: The position of the lens on axial sections could be clearly shown by using 25 MHz UBM. The D-value of the subluxated eyes was 1-2 mm longer than that of the normal ones. There was a statistically significant difference between 25 and 50 MHz UBM in showing subluxation of the lens, the testing time was significantly faster (2.0 min versus 7.5 min), and the diagnostic accuracy was much higher (98.0% versus 71.4%) with 25 versus 50 MHz UBM. Fifteen eyes with slightly subluxated lens were detected by 25 MHz UBM, and only one eye with slight lens subluxation was detected by 50 MHz UBM.
Conclusions: The results indicated that 25 MHz UBM has a greater diagnostic value than 50 MHz UBM in verifying the status of the lens subluxation and can provide reliable and quantitative imaging evidence for clinical use. This trial is registered with ChiCTR-DOD -15007603.