Variations in morphology and patency of disposable hydrodissection cannulas used in cataract surgery
Shwetha Mudalegundi1, Melissa Yao, Jesse Chew
1From the Intermountain Ocular Research Center, Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah (Mudalegundi, Yao, Kelkar, Eid, Driffill, Mamalis, Werner); Department of Ophthalmology, Providence Health Care, University of British Columbia, Vancouver, Canada (Chew); Utah Nanofab Electron Microscopy and Surface Analysis Lab, University of Utah, Salt Lake City, Utah (Perez).
Purpose:
To perform a detailed laboratory assessment of the variability in morphology (shape of opening port and surface finishing) and patency of Chang-style hydrodissection cannulas used in cataract surgery.
Setting:
John A. Moran Eye Center, University of Utah, Salt Lake City, Utah.
Design:
Experimental study.
Methods:
44 disposable cannulas from 3 different manufacturers were evaluated in this study. 17 cannulas were primed with solution and then underwent analyses under gross and light microscopy. 27 other cannulas were directly removed from the package and underwent the same abovementioned 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, and 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 seemed to be debris/residues. Fluid streams obtained with the cannulas also varied, and although 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 seemed to correspond to organic residues.
Conclusions:
The findings in this study raise concerns about potential damage to the capsule and toxic anterior segment syndrome. Priming before use in surgery is advisable to confirm appropriate fluid flow.
