Power adjustment for lenses placed in sulcus
Known as “the rule of the nines”: every 9 dp away from 0, remove 0.5 from the lens power.
Adjustment for lenses in “piggyback”
Adjustment when a new lens is needed in a piggyback situation. This formula doesn’t apply to lenses primarily intended for piggyback use (such as “Add-on”).
- Kim T, DelMonte DW, Gupta PK, Chang DF, Editors. Curbside Consultation in Cataract Surgery. 2nd ed. NJ: Slack incorporated; 2014:153–167
- Chang DF, Masket S, Miller KM, et al. Complications of sulcus placement of single-piece acrylic intraocular lenses: recommendations for backup IOL implantation following posterior capsule rupture. J Cataract Refract Surg. 2009;35(8):1445–1458. doi:10.1016/j.jcrs.2009.04.027