Intraocular lens materials and styles: A review

Abstract

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.

Hydrophilic acrylic intraocular lens optic opacification in a diabetic patient

“…Liliana et al [11,12] report calcified deposits on the surfaces of hydrogel and hydrophilic IOLs. Delayed opacification of hydrophilic foldable IOLs has been increasingly noticed as a late postoperative complication [3][4][5][6][7][8][9][10][11][12].…”

A study on the copolymerization kinetics of phenylethyl acrylate and phenylethyl methacrylate

“…2 Early IOLs were made from hard PMMA (poly(methyl methacrylate)) so that it required a big incision of 6 mm. 3 Nowadays, foldable soft IOLs are mostly used and therefore the incision is enough with 3 mm and the healing is more rapid.…”

Calcification of modern foldable hydrogel intraocular lens designs

“…Most of the currently available hydrophilic acrylic lenses are manufactured from different acrylic copolymers with water contents ranging from 18 to 28%, and an incorporated UV absorber. 1,2 They are packaged in a vial containing distilled water or balanced salt solutions, thus being already implanted in the hydrated state and in their final dimensions. Hydration renders these lenses flexible, enabling the surgeons to fold and insert/inject them through small incisions.…”