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Procedure increases lens stability and improves visual acuity in patients.
This article was reviewed by Ashkan M. Abbey, MD
Haptic flanging during a transconjunctival sutureless intrascleral (SIS) IOL fixation technique increases lens stability and improves visual acuity with minimal complications, according to a study presented by Ashkan M. Abbey, MD, of Texas Retina Associates in Dallas during the 2020 virtual American Society of Retina Specialists annual meeting.
Although rare, IOL dislocation after cataract surgery can be a severe complication, he said.
Abbey performed a retrospective chart review of 488 eyes that received SIS fixation of a 3-piece IOL with concurrent pars plana vitrectomy between September 2015 and September 2019 to assess the clinical outcomes, complications, and effectiveness of haptic flanging in reducing IOL dislocations.
All surgeries were performed by Abbey using transconjunctival fixation through 25- or 27-gauge trocar cannulas.
“This is the largest reported series of SIS fixation of IOLs using trocar cannulas,” Abbey said.
Pre- and postoperative best-corrected visual acuity (BCVA) and complications were evaluated in all patients. Abbey assessed the effectiveness of haptic flanging in reducing postoperative IOL dislocations as well as the effectiveness of intraoperative peripheral iridotomy to prevent reverse pupillary block.
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Patients were followed for more than a year (average: 444 days). There was a statistically significant improvement in postoperative BCVA compared with baseline (BCVA 20/355 versus 20/39, respectively).
IOL dislocation occurred in 13.7% of cases, with the vast majority in the first 3 months postoperatively. More than half of the dislocations (52.2%) occurred after IOL repositioning. The mean number of postoperative days prior to IOL dislocation was 85.2, he said.
“Several years into performing this procedure, I began to create flanges with low-temperature cautery in order to reduce the rate of IOL dislocation,” Abbey explained. “The data show a very clear and significant reduction in postoperative IOL dislocations in the flanged cases. The rate went from 18% in unflanged cases to 6.6% in flanged cases.”
Reverse pupillary block occurred at a much higher rate in patients without intraoperative peripheral iridotomy compared with those with intraoperative peripheral iridotomy, at 3% versus 0.4%, respectively.
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“In reverse pupillary block, the iris functions as a flap valve, allowing aqueous humor to pass from the posterior chamber to the anterior chamber, but not in the opposite direction,” Abbey said. “The aqueous humor trapped within the anterior chamber causes posterior bowing of the peripheral iris. This can lead to pigment dispersion, inflammation, elevated intraocular pressure, and pupil capture.”
Intraoperative peripheral iridotomy significantly reduced the chance of this occurring.
Patients who developed this complication had several commonalities including iridodonesis, use of tamsulosin for the treatment of an enlarged prostate (62.5% of cases), higher axial length, and high myopia.
To avoid this complication, Abbey recommended placing the haptics 2.75 to 3.0 mm posterior to the limbus as opposed to 2 mm in all patients who have an axial length greater than 26.5 mm.The most common complication was cystoid macular edema in 52 eyes (11%).
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Other complications included retinal detachment in 5 eyes and haptic exposure in 6 eyes, 2 of which were treated for postoperative endophthalmitis secondary to haptic exposure.
“To avoid this complication, grasp parallel to the distal tip of the haptic during externalization to avoid kinking the haptic, which can lead to erosion of the conjunctiva,” Abbey said. “Tuck the flanges into the scleral tunnel as far as possible, leaving the least amount of the haptic under the conjunctiva to cause erosion. All patients should be monitored regularly to ensure that there is not an erosion occurring at the conjunctiva.”
To summarize, Abbey provided a number of take-home points.
First, postoperative IOL dislocation in patients undergoing SIS fixation is most likely to occur after repositioning of a previously dislocated IOL.
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Second, IOL dislocation risk can be reduced if the clinician has a low threshold for exchanging a warped or damaged 3-piece IOL.
Finally, Abbey concluded that “flanging of the haptic tip significantly reduces the risk of IOL dislocation, and peripheral iridotomy significantly reduced the risk of postoperative reverse pupillary block.”
Read more by Michelle Dalton
Ashkan M. Abbey, MD
Abbey has no financial disclosures related to this content.