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Study: Iris-claw phakic IOLs keep safe distance during accommodation
Forward motion of ‘complex’ iris-crystalline lens-phakic IOL system makes a difference with angle-supported lens, surgeon says.
NAPLES – An optical coherence tomography study of the anatomical changes produced by accommodation in eyes implanted with iris-claw phakic IOLs demonstrated that a safe distance is maintained from the endothelium and the crystalline lens.
The study was part of the Artiflex European multicenter study in which a subgroup of 11 highly myopic patients were randomly implanted with the PMMA Verisyse-Artisan (Ophtec) in one eye and the silicone Artiflex (Ophtec) in the other eye.
“It was important to us because a possible contact between the anterior capsule of the crystalline lens and the posterior side of this style of phakic IOLs during the accommodation process was postulated by some investigators,” José L. Güell, MD, said at the annual joint meeting of Ocular Surgery News and the Italian Society of Ophthalmology.
Study
 José L. Güell |
All 11 patients had bilateral, non-simultaneous surgery. The PMMA lens was inserted through a 6-mm posterior biplanar corneal incision, and the silicone lens was implanted through a 3-mm direct posterior corneal incision. Exploration with the Visante anterior segment OCT (Carl Zeiss Meditec) was performed 20 to 36 months after surgery in all cases.
The only substantial difference between the two IOLs is that the different lens profile makes the Verisyse-Artisan lens vary in thickness according to the dioptric power, whereas the Artiflex size is not dioptric power-dependent. Apart from this, the two lenses behave in much the same way in response to accommodation movements, Dr. Güell said.
Only a linear progressive small reduction of anterior chamber depth was observed, which was important in consideration of the distance between the endothelium and the anterior IOL surface.
“The change was statistically significant in both groups, but no difference was observed between the two lenses, and a perfectly adequate space was maintained for endothelial safety,” he said.
A small but statistically significantly reduction in pupil diameter was also observed in both groups, again with no difference between the two lens models.
No changes at all were observed in the distance between the anterior crystalline lens surface and the posterior IOL surface.
“Because the lens is fixated to the iris, the whole ‘complex’ iris-crystalline lens-phakic IOL moves forward during accommodation, and this makes a huge difference with angle-supported lenses,” Dr. Güell said.
Extending the study
This study is being extended to include hyperopic patients, with more variables such as age and axial length.
“So far, the Visante OCT images of the hyperopic Verisyse are similarly reassuring, although the lens is implanted in a shallower anterior chamber,” Dr. Güell said.
The use of this imaging technology is mandatory to study the performance of IOLs, and preop and postop anatomic evaluation of the anterior segment of the eye should be performed in every candidate for IOL implantation, he said.
For more information:
- José L. Güell, MD, can be reached at I.M.O. c/munner 10, 08022 Barcelona, Spain; +34-93-2531500; fax +34-93-4171301; e-mail: guell@imo.es. Dr. Güell is a medical investigator for Ophtec and Carl Zeiss Meditec.
- Michela Cimberle is an OSN Correspondent based in Treviso, Italy, who covers all aspects of ophthalmology. She focuses geographically on Europe.