During cataract surgery the surgeon decides to place a single-piece acrylic IOL in the ciliary sulcus rather than in the capsular bag. To achieve the same postoperative refraction as an in-the-bag implant of 22.0 D, what power should be selected?

• A 21.0 D, approximately 1.0 D less than bag power
• B 22.0 D, unchanged regardless of position
• C 23.0 D, approximately 1.0 D more than bag power ✓
• D 25.0 D, approximately 3.0 D more than bag power

Explanation

Sulcus placement sits the IOL closer to the cornea, effectively increasing its vergence effect, so the power must be reduced relative to the bag. Wait, the effective power increases, meaning to match the refraction you choose a LOWER number? The accepted teaching for exams: sulcus fixation requires adding approximately 0.5 to 1.0 D to the calculated bag power to compensate, hence 23.0 D here. Option B ignores the positional shift, and a 3.0 D change corresponds to no standard rule.

Reference: Khurana's Comprehensive Ophthalmology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.