What induces negative dysphotopsia and how can we prevent it?

[caption id="attachment_6158" align="alignnone" width="350"] Samuel Masket MD[/caption] What induces negative dysphotopsia?” asked Samuel Masket MD, of the University of California, Los Angeles, USA. “And more importantly, how can we prevent it?” Dr Masket provided a solution to delegates attending the XXXIV Congress of the ESCRS in Copenhagen, Denmark. His presentation covered the use of an anterior capsulotomy-captured/grooved intraocular lens (IOL) to prevent negative dysphotopsia. “Negative dysphotopsia, although likely multifactorial in cause, is prevented, relieved or improved when the IOL optic edge overlies the anterior capsulotomy. Corrective or preventative surgery is based on that concept,” said Dr Masket. This is significant information. If the common pathway for negative dysphotopsia is any “in-the-bag” IOL with the anterior capsulotomy edge overlying the optic, then a profound and systematic alteration of surgical technique is required to prevent this complication. Dr Masket reviewed his own surgical experience regarding both therapeutic and preventative measures taken against negative dysphotopsia. “Considering 38 of 39 eyes with reverse optic capture successfully treated or prevented negative dysphotopsia, we sought an IOL solution with this in mind,” he said. Simply replacing an in-the-bag IOL with a lens in the sulcus is insufficient, and further, reverse optic capture and sulcus placement causes its own problems, including chafing of the posterior iris. Dr Masket thus designed an anti-dysphotopic IOL in which a groove on the anterior optic captures the anterior capsulotomy. “The IOL is fixated by the anterior capsule, so that part of the optic overlies the capsule rather than vice versa,” he explained. COMPLICATIONS The result of his research and development, the Masket Anti-ND IOL Morcher 90S lens, is currently CE marked in the European Union. Initial clinical results of 50 cases (different than the 39 described above) were very promising. “There were no cases of negative dysphotopsia, despite two failed optic captures,” he said. Complications included three cases of capsule block, of which two involved iris capture. There were, however, no cases of iris chafing. “We thus developed a modified version of the IOL with fenestrations to prevent capsule block,” he added. Because of the need for a highly precise anterior capsulotomy rhexis of 4.8-4.9mm, Dr Masket recommended using a femtosecond laser to perform the capsulorhexis. Besides the absence of negative dysphotopsias, fixation within the anterior capsulotomy ensures other advantages, such as highly stable fixation, avoidance of anterior capsule contraction, absence of lens tilt, a stable toric axis, excellent centration, a more predictable effective lens position and decreased higher order aberrations. Samuel Masket: avcmasket@aol.com

Tags: cataract and refractive, negative dysphotopsia