Performance of a Single-piece Toric Acrylic Intraocular Lens
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|ClinicalTrials.gov Identifier: NCT02155959|
Recruitment Status : Completed
First Posted : June 4, 2014
Last Update Posted : June 4, 2014
|Condition or disease||Intervention/treatment|
|Cataract Corneal Astigmatism||Device: toric intraocular lens|
Whereas first designs of toric intraocular lenses (toric IOLs) in the early 1990's showed an IOL rotation of more than 30° in one fifth of the patients, modern toric IOLs typically show a mean absolute rotation of 3° to 5°, which would result in a loss of about 10% to 15% of the astigmatism reducing effect of the toric IOL.
Rotational stability of a toric IOL depends on the interaction between the toric IOL and the posterior capsule, whereas misalignment of the toric IOL (defined in this study as the difference between the 3 months postoperatively measured axis of the toric IOL and the intended axis) depends on several factors additionally to rotational stability. Intraoperatively, misalignment may happen due to cyclotorsion of the eye in the lying position or due to peribulbar anaesthesia, and due to imprecision of the surgeon when positioning of the IOL relative to the intended meridian. Both these imprecisions can be dealt with by pre-operative marking of the eye in the sitting position and diligence by the surgeon. Postoperatively, the IOL may rotate because it is undersized for the capsule bag or due to the capsule shrinkage that takes place during fibrotic contraction of the bag in the postoperative period. Since most current IOLs are slightly oversized for the capsule bag, the former is observed rarely and would be more likely in long eyes which tend to have a larger capsule bag diameter. However, capsule bag shrinkage is thought to induce rotation in IOLs with open-loop haptics due to the asymmetry of the haptic design. Typical IOL haptic designs that improve rotational stability are either plate haptic IOLs or special Z-haptic shaped open-loop haptics that attempt to counteract the rotational effect of compression of the shrinking bag. However, both of these IOL designs are thought to have downsides. The former seems to have an increased risk of posterior capsule opacification due to a less effective lens epithelial barrier effect of the optic edge and may also show more rotation in the bag immediately after surgery due to the shorter haptic overall length. The latter IOL design, such as the Z-haptic IOL, is cumbersome to implant and may be prone to damage during implantation.
Aim of this study was to evaluate the rotational stability of a novel single-piece hydrophobic acrylic toric IOL with a C-haptic design.
|Study Type :||Observational|
|Actual Enrollment :||30 participants|
|Official Title:||Rotational Stability of a Single-piece Toric Acrylic Intraocular Lens: a Pilot Study|
|Study Start Date :||March 2011|
|Actual Primary Completion Date :||December 2012|
|Actual Study Completion Date :||December 2012|
one group receiving a toric intraocular lens during cataract surgery.
Device: toric intraocular lens
toric intraocular lens
Other Name: Tecnis toric IOL (Abott Medical Optics, USA)
- Rotational stability of the investigated toric lens [ Time Frame: 3 months ]Rotation of the investigated intraocular lens using a photograph technique (retroillumination images) immediately after surgery and 3 months later.
- reduction in post-operative higher order aberrations [ Time Frame: 3 months ]the investigated intraocular lens was proven to reduce some higher order aberrations (this is a refractive problem caused by the cornea). It was shown that the investigated intraocular lens was reducind higher order aberrations in our study population.
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02155959
|Principal Investigator:||Oliver Findl, MD, MBA||Vienna Institute for Research in Ocular Surgery|