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Advances in Cataract Surgery

US Sensory Disorders Review, 2006:20-3 DOI: http://doi.org/10.17925/USOR.2006.00.00.20
Received: January 11, 2011 Accepted: January 11, 2011

Cataract surgery transformed radically this past century. From cocaine topical anesthesia, immobilized patients, and extracapsular technique on ‘ripe’ cataracts we advanced to retrobulbars, sutured incisions, and intracapsular technique. Today’s techniques recapitulate those of old, with topical anesthesia and intact capsular bag support of implants enabling virtually instant visual recovery, minimal discomfort, and immediate resumption of full activity, often spectacleless, with unparalleled safety.

The ability to remove the cloudy lens through a small, stable incision, leaving the zonular capsule complex intact combined with technology to refocus light rays clearly onto the retina facilitate today’s extraordinary outcomes.These results are often achieved even in eyes with compromised anterior segment anatomy.

Technique
Phacoemulsification, capsulorhexis with its subtleties and viscoelastics permit the removal of any stage cataract through a tiny self-sealing clear corneal incision. Advanced incision architecture nearly eliminates induced astigmatism and permits immediate stable postoperative refractions. Reliable intracapsular implantation enhances accurate implant power calculation.

The Pursuit of Spectacle Freedom
Intraocular lens (IOL) selection formulae have been evolving with the realization that eyes are not always proportional in size. By incorporating white-to-white measurement into calculations traditionally only including axial length and corneal shape, the significant percentage of myopes and hyperopes with normal size anterior segments are accounted for, thereby reducing outliers.

Two lenses are rarely piggybacked since high hyperopia can now be addressed with aspheric IOLs measuring up to 40 diopters.The potential benefit of two lenses must be weighed against the risk of inter-lenticular opacity, which could defy yttrium aluminum garnet (YAG) laser correction. This incidence may approach zero when the capsulorhexis does not cover the IOL edges or when one lens is in the bag and the other is in the sulcus. Piggybacking proves useful to correct refractive surprises without a lens exchange, thereby minimizing the risk of bag rupture and inaccurate calculation. Existing low plus and minus power foldable IOLs provide an almost unlimited range of correction. Narrow-profile sulcus lenses minimize the risk of pigmentary dispersion. Low-power multifocal or pseudo-accommodative lenses to piggyback over preexisting monofocal lenses for pseudophakic presbyopia remain rarely used but available.

Pre-existing refractive error is addressed by proper lens selection for spherical power and treatment of astigmatism. Toric lenses provide an alternative to corneal incisional techniques such as astigmatic keratotomy. In the majority of cases, with pre-operative topography and intra-operative keratoscopic confirmation, both methods are predictable up to two diopters. ‘Bioptics’—intentionally planning laserassisted in situ keratomileusis, (LASIK) combined with IOL implantation—can be used for higher degrees of astigmatism. Healing is rapid, and complications few.