Primary polypseudophakia is a relatively recent concept in ophthalmology. Optically,
polypseudophakia would be considered a special intraocular lens consisting
of two rotationally symmetric elements. The first report of the placement of
two intraocular lens implants back-to-back in a highly hyperopic eye was by
Jim Gills, MD in 1993. With dramatic advances in foldable lens technology allowing
for small, self-sealing incisions, this procedure originally gained a qualified
general acceptance. However, the previous practice of stacking two acrylic
lenses in the capsular bag has since been abandoned due to occasional problems
with interlenticular opacification and reduced visual acuity.
When the calculated IOL power exceeds that available, and placement of a single IOL would result in an unacceptable refractive outcome it is often worthwhile for the surgeon to place two IOLs in the eye at the same operative session. This is typically seen in patients with axial lengths less than 20.00 mm, and often with a hyperopic spherical equivalent of +8.00, or greater.
With current technology, the preferred approach is to place two IOLs of different materials in different locations (e.g., a lower power, thin, biconvex silicone lens in the ciliary sulcus and a higher power negative shape factor acrylic lens in the capsular bag). This is commonly referred to as primary
polypseudophakia. With the recent introduction of very high power, foldable, aspheric, hydrophobic acrylic IOLs available in powers up to +40.00 D (SA60AT - Alcon Laboratories, Ft. Worth, Texas), the need for primary polypseudophakia should become less frequent. Secondary polypseudophakia would be something like a piggyback IOL to correct a refractive surprise months or years after the original surgery.
Formula
