In A-scan biometry for intraocular lens power calculation, the immersion technique is preferred over the applanation technique because it:

• A Requires topical anesthesia
• B Uses a higher frequency ultrasound probe
• C Is faster and easier to perform
• D Prevents corneal compression and falsely short axial length readings ✓

Explanation

Applanation A-scan can compress the cornea, artificially shortening the axial length and leading to hyperopic surprises postoperatively. Immersion A-scan avoids direct corneal contact, preventing compression and providing more accurate axial length measurements. Both methods require anesthesia, and speed is not the primary clinical advantage.

Reference: AAO BCSC Section 11: Lens and Cataract, 2022-2023 ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.