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Anterior Segment Intraocular Lens
Refractive Aspect of Cataracts – Towards Customisation
Pascal Rozot and Jean-Claude Rigal-Sastourne
Clinique Monticelli, Marseille
Abstract
Currently, posterior chamber intraocular lenses (IOLs) correct totally or partially spherical aberrations. In this article we present the visual
results of a prospective multicentre study evaluating the Micro AY IOL correcting 0.11µm of spherical aberration, which is a good compromise
between optimal vision and a consistent depth of focus. We evaluated 124 eyes that were operated on using bi-manual micro-cataract surgery
(BiMICS: 75%) or co-axial micro-cataract surgery (CoMICS: 25%) phacoemulsification with insertion of a Micro AY IOL through a 1.8–2.2mm
incision. Mean post-operative best corrected visual acuity was 0.97±0.25; pre-operative spherical aberrations were +0.24±0.13µm, and
reached +0.10±0.11µm post-operatively. There were no complications due to the lens, and photopic contrast sensitivity reached high levels.
Keywords
Phacoemulsification, posterior chamber intraocular lens, spherical aberrations, contrast sensitivity, depth of focus
Disclosure: The authors have no conflicts of interest to declare.
Received: 9 November 2009 Accepted: 3 December 2009
Correspondence: Pascal Rozot, Clinique Monticelli, 88 rue du Commandant Rolland, 13008 Marseille, France. E:
pascalrozot@sfr.fr
Whether bi-manual or co-axial, the microincision phacoemulsification On the other hand, depth of focus induced by implants correcting
techniques of today allow for a neutral cylinder, thus reducing SAs can be reduced, but this is not an established fact as different
high-degree aberrations (in particular the coma type). The hydrophilic studies have sometimes given conflicting results.
acrylic intraocular lenses (IOLs) are more compliant as they are
inserted through a minimum 1.6–1.8mm incision, whereas the The results of a prospective multicentre study carried out by four
hydrophobic IOLs are inserted through 2–2.2mm incisions but surgeons concerning a microincision implant (see Figure 1) offering a
generate fewer secondary cataracts. The general idea of aspherical -0.11µm asphericity through a 1.8mm incision (Micro AY implant
IOLs is to compensate all or part of Z4 types of positive corneal made by PhySIOL laboratories) are presented here, covering 124
spherical aberrations (SAs) with a properly adapted optic. On average, cases of senile or pre-senile cataracts. The population was made up
corneal spherical aberrations are +27µm for a 6mm pupil, which of 54% females and 46% males, of whom 23% presented cortical type
corresponds to a mean Q co-efficient of -27. In order to choose the of cataract, 58% nuclear cataracts and 19% subcapsular cataracts.
correct asphericity profile, the patient’s corneal profile must first be Mean age was 73.5±8.3 years (range 51–89 years). Topical
studied by measuring not only the Z4 and Q factor but also his/her anaesthesia was used in 96% of cases with 100% clear cornea
keratometry data. It is necessary to know the levels of asphericity of incisions. The incision was temporal in 59% of cases, 27% on the most
the different IOLs on the market and finally to take into consideration arched meridian and superior in 3% of cases. The bi-manual
the power of the implant. technique was used for 92 (74.2%) of patients. The mean incision for
phacoemulsification was 1.41mm for all of the interventions and
Current corneal topographic devices measure the value of the Q 1.95mm for implantation.
factor directly, as well as the spherical distortions of each cornea.
Historically, the first implants totally compensated corneal SAs, but Mean endothelial cell loss was 6%. Of 101 cases, uncorrected visual
over the last few years we have been aiming at only partial correction acuity was 0.72±0.22 at three months and best corrected visual acuity
of these SAs in order to achieve the best visual result, which we know (BCVA) was 0.97±0.25 (see Figure 2). Post-operative spherical
is obtained with approximately +0.10µm total residual SA.
1
As equivalent was -0.36±078D (compared with 0.51±2.31D pre-
correction of SAs also provides a better contrast sensitivity in operatively). Pre-operative cylinder was -0.34±0.87 and reached
photopic and mesopic conditions, the main clinical interest in -0.14±0.71D post-operatively. In aberrometry, the pre-operative
correcting spherical SAs is specifically seen in mesopic and scotopic corneal Z4 were +0.24±0.13 (from -0.09 to +0.31) and reached
conditions with a pupil dilated at approximately 6mm, which improves +0.10±0.11µm (from -0.12 to +0.24) post-operatively. No complications
the ability of night driving. With this in mind, it can be interesting to were due to the implant: there were no problems during insertion with
systematically carry out corneal topography on all young patients the PhysIOL injector, no decentration, no IOL deposits and no posterior
having undergone cataract surgery in order to optimise their vision capsule early opacity (see Figure 3). Results for contrast sensitivity are
in these conditions,
2
because we know they will be driving at night. presented in Figure 4; depth of focus (DF) was compared with a series
80 © TOUCH BRIEFINGS 2009
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