Sulcus IOL Power Adjustment: How Much to Reduce and When Not To

Last updated: October 2026

Short answer: an IOL placed in the ciliary sulcus sits further forward than one in the capsular bag, so it acts more strongly. You therefore reduce the IOL power, typically by 0.5 D for lower powers and 1 D or more for higher powers. If you can capture the optic through an intact capsulorhexis, use the in-the-bag power instead.

How much to reduce

A commonly cited approach, based on a study summarised by the American Academy of Ophthalmology, adjusts the reduction by the predicted in-the-bag power:

Higher-power lenses (shorter eyes) are more sensitive to a change in position, which is why they need a larger reduction. Short eyes (below about 22 mm) also showed larger refractive errors.

Optic capture changes the rule

• If the haptics are in the sulcus but the optic is captured behind an intact, well-centred anterior capsulorhexis, the optic sits close to the in-the-bag position.
• In that case, use the in-the-bag power without reduction.
• Optic capture also improves centration and stability, so it is preferred whenever the capsulorhexis allows.

Choosing the right lens for the sulcus

• Use a three-piece IOL designed for sulcus placement, with an overall length long enough to remain stable.
• Avoid single-piece acrylic IOLs in the sulcus. Their thick, square haptics can rub the iris, causing pigment dispersion, raised IOP, uveitis and hyphaema (UGH syndrome), as well as decentration.
• If the anterior capsule cannot support the lens either, consider an anterior chamber IOL or a scleral-fixated lens.

Frequently asked questions

Related: PCR management flowchart, biometry rules of thumb and IOL calculators.