Centration of intraocular lenses with circular haptics

To evaluate two intraocular lens (IOL) models with a circular haptic configuration designed to better distribute forces within the capsular bag over 360 degrees.

University and Maria Middelares hospitals, Antwerp, Belgium.

Two IOLs with circular haptics were evaluated for 6 months after implantation: a one-piece, all-poly(methyl methacrylate) (PMMA), Corneal IS M 5.5 lens with a 5.5 mm biconvex optic, overall diameter of 9.8 mm, and two semicircular open haptics (n = 103); a plano-convex, all-PMMA, modified Anis lens with a 5.5 mm plano-convex optic, total diameter of 10.0 or 11.0 mm (depending on diopter), and closed-loop haptics (n = 335). All lenses were inserted through a 5.5 mm scleral incision after phacoemulsification and placed in the capsular bag through a 4.5 mm curvilinear capsulorhexis. The IOLs centered without being rotated.

Six months after implantation, the IOL optics were well centered, even in eyes with an eccentric capsulorhexis (19%). In two eyes with partial zonulysis and in seven with posterior capsule rupture, decentration of less than 0.5 mm was observed. Both lenses provided uniform capsular support without causing stress lines in the posterior capsule. There were no cases of capsule contraction syndrome. Posterior capsule fibrosis reducing visual acuity occurred in 4% of eyes in both series.

The Corneal IS M 5.5 and the Anis lens with circular haptics prevented late optic decentration and, therefore, would be useful in cases of eccentric capsulorhexis, partial zonulysis, anterior radial tears, and posterior capsule rupture. These IOLs may also prevent capsular contraction.