1178: AC IOL orientation & calculations

Anterior chamber IOLs (AC IOLs) are not often used, but there will be a time where just about every cataract surgeon will need to implant one. We have previously explained the correct orientation of AC IOLs in this post and today’s video will serve as a refresher. You should not typically use your corneal phaco incision to insert an AC IOL because they require a very large incision of about 6 mm in width. The AC IOLs are usually made of PMMA which is a rigid and non-foldable material. These AC IOLs are also anteriorly vaulted and designed to be sized to each eye. There is an overall length sizing in addition to the dioptric power of the optical. The common guideline is to measure the horizontal white-to-white diameter and then add 0.5 mm to get the desired overall length for the AC IOL. I prefer to make a separate scleral tunnel incision in order to insert the AC IOL.

Is a scleral fixated IOL a better choice than an AC IOL? Many studies have shown no appreciable difference in the patient’s visual outcome whether an AC IOL is used or a PC IOL is fixated to the sclera using a Yamane technique, Canabrava method, Gore-tex sutures, or other technique. Note that a properly placed AC IOL has the footplates in the angle and there is no iris tissue caught underneath them. A peripheral iridotomy is also required in order to prevent pupillary block. For the dioptric power calculation, the “rule of thumb” that your friend taught you is probably not correct… I explain why in the video

click to learn about AC IOL orientation and calculations: