Abstract
Purpose :
The new EnVista IOL has gained popularity for scleral fixation using Gore-Tex passed through its eyelets, but eyelet fracture has not been reported. Moreover, we tested the eyelet's tensile strength under two different suturing methods to determine whether a stronger option existed.
Methods :
A chart review of all patients with a scleral sutured EnVista IOL at the University of Mississippi Medical Center was performed to identify patients with a dislocated lens. To determine Envista eyelet tensile strength, Envista IOLs (model MX60E) were suspended in a tank containing balanced salt solution with suture passed through each eyelet and oriented either perpendicular to the plane of the optic (simple pass) or over the lens haptic (suture over haptic pass). Force was gradually applied to the sutures by addition of known weights until an eyelet broke. The eyelet's tensile strength was calculated for each method and the location of eyelet fracture was noted. A student's T-test was used for statistical analysis.
Results :
3 cases of dislocated Envista IOL were identified out of 17 surgeries. The mean eyelet tensile strength for IOLs suspended by simple pass was 0.27 N +/- 0.017N (n=3). It was 0.15 N +/- 0.016 N (n=3) for IOLs suspended by suture over haptic. Significantly more force can be applied on the eyelets with the simple pass than the suture over haptic method (p=.0015). The simple pass fractured the distal haptic wall of the lens eyelet whereas the suture over haptic pass fractured the proximal optic-haptic junction.
Conclusions :
To our knowledge, this is the first official report of Envista lens dislocation using its eyelets for Gore-Tex scleral fixation. Eyelets can withstand more force sutured with simple pass than with suture over haptic pass. The two methods impose stress on different regions of the eyelet wall. This difference in tensile strength and stress application positioning suggests that the simple pass method may better prevent lens dislocation and may influence the suturing strategy for future scleral fixation of this IOL. Regardless of method, care must be taken not to overstress the eyelets during IOL fixation to avoid dislocation.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.