Abstract
Purpose: :
Evaluation of anterior-posterior position changes of a phakic anterior-chamber angle-supported intraocular lens (PIOL) (Cachet, Alcon) during accommodation.
Methods: :
Bilateral implantation of the PIOL in 13 patients (8 male, 8 female, 36,±35,36 years). Assesment of defocus curves (1D steps from -7D to +1D) has been performed at the ETDRS Charts (Vectorvision) preoperatively and one month postoperatively. At the same time points measurement of pupil diameter (PD), anterior chamber depths (ACD) and (one months postoperative) intraocular distances of the PIOL to the corneal endothelium (M1) and the natural lens (M2) has been performed using optical coherence tomography (Visavte OCT, Zeiss) with the respective accommodative stimuli. Statistical analysis was performed using Shapiro-Wilk testing, one-sample t-test and Wilcoxon’s signed ranks test, the overall significance was set to p=0.05.
Results: :
ACD and PD did not change significantly from pre- to postoperative measurements for any accommodative stimulus. A significant change in postoperative intraocular distances was shown with the one-way t-test compared to 0D acommodative stimulus reference value (REF) for M1 at stimuli of -7D and -6D (REFM1=2.15mm, ΔM1,-7=-0.09mm und ΔM1,-6=-0.08mm) as well as for M2 at stimuli of -5D and -4D (REFM2=0.79mm, ΔM2,-5 = ΔM2,-4=-0.09mm). A trend towards slight foward movement of the IOL was seen. The defocus curve showed a significant improvement (Wilcoxon’s signed ranks test) of visual acuity from pre- to postoperative status for accommodative stimuli from -4D to +1D. Best corrected visual acuity (BCVA) was -0.01±0.09 logMAR preoperative and 0.07±0.07 logMAR postoperative.
Conclusions: :
The PIOL showed a slight tendeny towards forward movement during accommodation, however, this was mostly not significant nor clinically relevant. Patients gained approximately one line of BCVA with no decrease in accommodative range.
Keywords: accommodation • refractive surgery: phakic IOL