Revised design avoids capsule block, iris capture, may be available soon
An innovative intraocular lens (IOL) intended to eliminate negative dysphotopsia has been redesigned to address early complications, Samuel Masket MD told the American Academy of Ophthalmology Annual Meeting in New Orleans, USA.
The Morcher 90S anti-dysphotopic lens (Stuttgart, Germany) incorporates a groove around the optic that accepts the circular anterior capsulotomy so that the anterior lens surface overlaps the capsulotomy edge, apparently eliminating negative dysphotopsia, a shadow on the visual field that as many as 15% of patients may see after cataract surgery.
The idea came from treating negative dysphotopsia by implanting a conventional IOL with haptics in the capsule and the optic reverse captured outside the anterior capsulotomy, or placing the lens in the sulcus, said Dr Masket, who patented the design. The one-piece, foldable, hydrophilic acrylic lens is intended to provide the anti-dysphotopic advantages of the optic overlapping the capsulotomy, while preventing the capsule opacification and fibrosis often seen with reverse optic capture, and decentration and iris chafing seen with sulcus placement. Capturing the optic in the capsulotomy provides a number of additional benefits, among them a stable axis for toric IOLs.
“With 100 anti-dysphotopic lenses of all versions implanted so far, no patient has yet reported a negative dysphotopsia. We consider this adequate proof of concept,” reported Dr Masket, of Advanced Vision Care and the UCLA Stein Eye Institute, Los Angeles, USA.
However, of 39 eyes implanted with the original 90S design, three experienced capsule block, in which fluid trapped behind the lens distended the capsular bag, and two optic capture by the iris.
The 90S was redesigned with holes at the optic-haptic junction to prevent capsule block, Dr Masket said. In 48 cases no capsule block was seen, but iris-optic capture occurred in five. Of the seven iris-optic captures in the first 87 cases, five were re-operated and two lenses explanted, Dr Masket said.
Potential causes for iris-optic capture included wound leak, pupil block and a thick hydrophilic acrylic optic, Dr Masket said. Potential cures included a thinner, hydrophobic acrylic lens material and thinner groove, an enlarged anterior optic and pupil miosis for the first few days after surgery.
The third version of the 90S IOL retained the fenestrations of the second version and increased the diameter of the anterior optic outside the capsule to 6.4mm from 6.0mm. Of 13 lenses implanted so far, no capsule block or optic capture have been observed, Dr Masket reported.
With the newer designs, capsule block has been eliminated and optic capture reduced or eliminated, Dr Masket said.
Samuel Masket: firstname.lastname@example.org