Objectives: To compare the anterior chamber depth (ACD) using ultrasonic and optical measurements.
Material and Method: In this prospective study, ultrasound and optical (Orbscan) devices were employed to measure ACD in 42 eyes of 21 myopic volunteers. ACD values were compared using the paired-sample Student t test. The correlation of ACD values obtained from two groups was assessed by linear regression analysis.
Results: The difference of mean ACD values between the ultrasound (3.02 + 0.37 mm) and Orbscan (3.56 + 0.42 mm) method was statistically significant difference (p < 0.0001).
Conclusion: The optical measurement of ACD in healthy myopic Thai eyes is, on average, 0.54 mm greater than ultrasonic measurement; however, both methods posses a significant linear correlation.

Keywords: Anterior chamber depth, Orbscan, Ultrasound