Lenses foldable

The substitution of the crystalline lens for a transparent intraocular lens (lOL) has become an integral part of almost all cataract operations. Because the implantation of the lOL is done through a small incision, foldable lenses have been developed, some of which are PHEMA hydrogels (refractive index, 1.44 water content, 38%o) or HEM A copolymers with... 

In lens implantation, a viscoelastic substance is capable of giving more resistance than air or BSS (balanced salt solution). Furthermore, a viscoelastic offers other helpful properties, such as occupying and maintaining space and protecting the corneal endothelium. In the implantation of foldable lenses, the following rheologic characteristics are worth observing ... 

The manual implantation of foldable lenses (Fig. 87) is substantially facilitated by and less complicated with a deep, stable anterior chamber and an evenly extended posterior capsule. For introduction of the folded lOL into the capsular bag (Fig. 88), lOL positioning before unfolding (Fig. 89) and the controlled unfolding in the capsular bag, viscoelastic substances of high viscosity and elasticity at low shear rates (e.g., Healon GV) should be applied. Following implantation, aspiration (Fig. 90) is more easily achieved with cohesive viscoelastic substances than with disperse viscoelastics. 

Kohnen T, von Ehr M, Schiitte E, Koch DD. Evaluation of intraocular pressure with Healon and Healon GV in sutureless cataract surgery with foldable lens implantation. J Cataract Refract Surg 1996 22 227-237... 

Kohnen, T. The variety of foldable intraocular lens materials. J. Cataract Refract. Surg. 1996, 22, 1255-1257. 

Rath R, Singh AD, Singh A. Cartridge cracks during foldable intraocular lens insertion (letter). J Cataract Refract Surg 1999 25 306... 

Koch MU, Kalicharan D, Vanderwant JJL. Lens epithelial cell formation related to hydrogel foldable intraocular lenses. J Cataract Refract Surg 1999 25 1637 0. 

Izak AM, Werner L, Pardey SK, Apple DJ. Calcification of modern foldable hy(h ogel intraocular lens designs. Eye 2003 17 393 06. 

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