Refractive effect of reversed implantation of angled-haptic lens implants.

Background: To study the refractive effect of reversed implantation of intraocular lenses.

Methods: Trigonometric calculations were used to calculate the extent of forward displacement of the optic for various lens designs available commercially. The SRK formula was used to estimate the relationship of axial length to the refractive power of the eye, with other variables remaining constant.

Results: The theoretical effect of a displaced posterior-chamber implant due to flipped insertion can vary from 1.46 dpt for a 12.5-mm diameter lens with an optic diameter of 6 mm (or a 13-mm diameter lens with an optic diameter of 6.5 mm) and a haptic angle of 5 degrees to 3.15 dpt for a 12.5-mm diameter lens with an optic diameter of 5.5 mm (or a 13-mm lens with an optic diameter of 6 mm) and a haptic angle of 10 degrees.

Conclusions: There has been no study on the refractive effect of axial lens displacement due to a reversed implantation of a lens with a hinged haptic. This study identifies the major determinants (namely the haptic length and haptic angle) and gives an estimate of the effect on final refraction for each lens type commonly used when they are implanted on the reverse.