Variations in morphology and patency of disposable hydrodissection cannulas used in cataract surgery.

Abstract

Purpose: To perform a detailed laboratory assessment of the variability in morphology (shape of opening port and surface finishing), as well as patency of Chang-style hydrodissection cannulas used in cataract surgery.

Setting: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

Design: Experimental Study.

Methods: A total of 44 disposable cannulas from 3 different manufacturers were evaluated in this study. Seventeen cannulas were primed with solution, and then underwent analyses under gross and light microscopy. Twenty-seven other cannulas were directly removed from the package, and underwent the same above-mentioned analyses, before priming. Selected cannulas from the 3 manufacturers were also evaluated under scanning electron microscopy and surface analyses for elemental composition.

Results: There was variability in all parameters evaluated in this study, including opening ports that were irregular in shape, partially or totally blocked, as well as a cannula with a second, lateral opening port. The surface finishing of the tips of the cannulas was also variable, with cannulas exhibiting irregular and/or sharp edges, as well as what appeared to be debris/residues. Fluid streams obtained with the cannulas also varied, and while some cannulas produced a normal stream, others produced a weak stream, no stream, or double stream. All cannulas were composed of stainless steel, and debris/residues appeared to correspond to organic residues.

Conclusion: The findings in this study raise concerns about potential damage to the capsule, as well as toxic anterior segment syndrome. Priming before use in surgery is advisable to confirm appropriate fluid flow.