Intraocular lens materials and styles: a review.

Biomaterial science has lead to the development of a variety of foldable intraocular lens (IOL) biomaterials. This literature review examines these lenses from both a basic science and a clinical perspective. By most parameters, hydrogel, soft acrylic and silicone IOL are better than polymethylmethacrylate (PMMA) lenses. Plate haptic silicone IOL have the lowest incidence of cystoid macula oedema and posterior capsule opacification, but these lenses require an intact anterior capsularhexis and posterior capsule. Yttrium aluminium garnet (YAG) laser capsulotomy must be delayed at least 3 months to avoid posterior lens dislocation. Silicone has the lowest threshold for YAG laser damage of all IOL materials and also adheres irreversibly to silicone oil with subsequent optical impairment. Three piece silicone IOL with polypropylene haptics have a higher incidence of decentration, pigment adherence and capsule opacification compared with PMMA haptics. Hydrogel lenses are very biocompatible and resistant to YAG laser damage, but pigment adheres to the surface more readily than PMMA. Soft acrylic IOL unfold slowly, resulting in controlled insertion, but it is possible to crack the lens and some lenses develop glistenings due to water accumulation. There are significant socioeconomic implications to the large differences in posterior capsule opacification rates between the various biomaterials and the lens styles.