| Abstract |
Purpose:
Το evaluate the optical performance, safety and efficiency of the Acrysof
Restor multifocal diffractive intraocular lens, with subjective (visual acuity and
contrast sensitivity) and objective (wavefront analysis) methods.
Method:
Fourteen eyes, out of ten patients aged 55 to 83, with advanced cataract (no
other pathology of the eyes) and pre-operative visual acuity from 0,1 to 0,3,
underwent replacement of the cataract crystalline lens with the Acrysof Restor
(Alcon Laboratories) multifocal intraocular lens. In three out of the ten patients
the insertion of the lens was binocular and in the seven left was monocular.
The pre-operative examination included the maximum distant uncorrected
visual acuity (UCVA), the maximum distant best spectacle corrected visual
acuity (BSCVA) in decimal score, the maximum near uncorrected visual acuity
(in Jaeger scores) and evaluation of the contrast sensitivity function using the
Optek 6500 Vision Tester (in two patients). The pre-operative selection of the
patients also included corneal topography, ultrasound biometry and slit lamp
examination of the anterior and posterior segment of the eye. In the postoperative
examination wavefront aberrations analysis (after pupil dilation, for a
5mm pupil diameter) was additionally performed with the COAS analyzer
(Wavefront Sciences), which is based on the Shack-Hartmann principle. The
operation was performed by the same surgeon under the typical procedure of
phacoemulcification. The post-operative examinations performed one and
three months after the operation.
Results:
The average maximum UCVA was 0,714 (variance 0,5 -1), BSCVA was 0,84
(variance 0,6-1) and the average maximum near UCVA was Jaeger 1,93
(variance 1-6) at the first month. In the third month there was an improvement
in UCVA: 0,8 (variance 0,5-1), BCVA: 0,9 (variance 0,6-1) and near UCVA:
Jaeger 1 with no variance. The refractive errors showed a reduction postoperatively:
specifically, three months following the operation the average
sphere was +0,34 D and astigmatism -0,73 D. The contrast sensitivity function
showed improvement post-operatively and further improvement between the
first and third month, under all lighting conditions. Under photopic conditions
the contrast sensitivity function was approaching the normal one for the same
age group (with no cataract), with lower measurements in the higher
frequencies (12 & 18 cycl/deg). Under mesopic conditions there was a
reduction in relation to the photopic conditions for all frequencies. The
wavefront analysis revealed normal higher order aberrations, as compared to
age-matced data from population studies. There were fluctuations between
one and three months, possibly due to the ocular post-operative healing. An
increase in coma-like aberrations and normal spherical aberration values was
also observed at three months post-operatively. In comparison with the
studies concerning monofocal intraocular lenses implantation, the Restor
group showed an increase in coma-like aberration and a reduction in
spherical aberration. The former is probably due to a post-operatively
decentration or tilt of the lens, which is further supported by the increased
values in astigmatism. The increased aberrations do not have a strong effect
on either visual acuity or the contrast sensitivity function. Patients with
binocular implantation of the lens did not need any refractive correction for
distant or near vision. No patient complained about visual reduction during the
night and only two of them experienced halos around light sources.
Conclusions:
The Acrysof Restor multifocal apodized diffractive IOL provides satisfactory
uncorrected distant visual acuity with an improved near uncorrected visual
acuity. The contrast sensitivity under photopic conditions is within normal
limits, but under mesopic conditions a reduction was observed, which may be
due to higher order aberrations at large pupil sizes. Distant or near glasses
were not needed and the patients were satisfied with the IOL visual
performance.
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