Purpose: Comparison of contact technique with immersion technique in terms of axial length measurements in cataractous eyes & to compare prediction errors in these eyes as measured after surgery.

Materials & Methods: Randomised control study done in 101 patients from December 2019 to June 2022. IOL Power was calculated using SRK/T formula in both groups. Prediction error was compared along with BCVA in contact and immersion technique.

Results: Postoperatively out of 51 cases 24 cases (47.05%) were in the estimated target refractive group (-0.25 to -1 D) and immersion group showed 49 cases (98%) within the estimated target refractive group (-0.25 to -1D). Mean prediction error in contact group was -0.85 ± 0.74 and immersion group -0.25 ± 0.16 with “p” value of <0.001 which is clinically significant.

Conclusion: There was a significant difference in ocular biometry measurement with the contact and immersion ultrasound technique. Precision of immersion technique is better than contact technique.

Keywords: Axial length measurement; Contact technique; Immersion technique; Prediction error.