The Array lens is a multifocal spherical lens with five progressive rings. It is available in lens powers from 6.0 D to 30 D in 0.5 D steps and requires an incision size no greater than 2.8 mm for implantation. Indications for the Array lens now include cataract in axial ametropia, presbyopic lens exchange, paediatric cataracts and unilateral cataracts in young people.

Unlike other aphakic lenses currently in use for the treatment of presbyopia, the Array has been extensively investigated for over 10 years for the treatment of cataract and high ametropias. Its refractive stability and long-term safety are well documented.

Predictability of the Array lens in Myopia

Predictability of the Array lens in Hyperopia

oreover, newer lenses such as the accommodative IOLs with flexible haptics have a narrow refractive range that makes them unsuitable for patients with high ametropias. Their lens powers range from 16 D to 27 D.

"This really limits your options with refractive lens exchange because you need the low dioptre and the very high dioptre IOL powers if you want to not only help presbyopic patients but also deal with high ametropia."

Moreover, their accommodative function is dependent on the capsular bag for the correct function of the flexible haptics. With their current design they may therefore be unsuitable for myopic patients because their large capsular bag diameter exceeds that of the haptics. Furthermore even among patients with normal eyes implanted with the accommodative lenses many will not achieve accommodation, he said.

"You cannot guarantee refractive lens exchange candidates an accommodative effect with these lenses."

There are also unanswered questions regarding the effect capsular bag diameter, bag shrinkage and fibrosis will have on long-term functionality of the lenses.

Dr Dick noted that some new multifocal IOLs are beginning to enter the market. However, they have yet to undergo extensive trials and as with the accommodating IOLs the follow-up is still fairly short.

In contrast, the AMO Array has been investigated extensively, and at least 99 studies involving the lens have appeared in peer-reviewed journals. The published studies address all the issues relevant to refractive lens exchange including long-term refractive outcome and stability, biometry data and surgical technique.

Furthermore, the follow-up with the lens has been sufficient for the FDA to recently approve AMO’s claim of a low PCO rate with the lens.
He noted that his own personal experience with the lens includes a series of 24 myopic and 26 hyperopic eyes. All achieved postoperative refraction within 1.0 D of emmetropia and most were within +/- 0.5 D. Furthermore the refractive outcome was stable over six months of follow-up.

The most crucial factor in achieving an optimal outcome in patients with the AMO lens is to achieve emmetropia.

Dr Dick also strongly recommended using partial coherence interferometry measurements with the IOLMaster rather than ultrasound when performing lens power calculations. Several studies have demonstrated that the OCT device provides much more reliable and reproducible measurements than ultrasound devices. Moreover, they can always be used in presbyopes because their natural lens is very clear.

Predictability of the Array lens in Myopia

Predictability of the Array lens in Hyperopia

He noted that the Array lens’ low incidence of PCO can be further reduced through the use of a capsular bending ring. The injectable PMMA ring is manufactured by Morcher in Stuttgart, Germany. It has height of 0.75 mm and its outer surface blocks the epithelium and significantly reduces the risk of PCO.

He also said that it is important to emphasise to patients that there is a great likelihood that they will experience some photic phenomena, although neuroadaptation tends to minimise the effect over time.

"Patient selection is crucial. You have to emphasise that they should expect to see photic phenomenon with these lenses irrespective of whether they see them or not. You will see that in patients with co-existent ametropia the patient satisfaction will be very high with the Array lens. "

Verisyse lens in the management of amblyopia
Jean-Michel Bosc MD told the symposium that refractive lens implantation is beginning to play a role in the treatment of amblyopia.

"In current practice refractive surgery doesn’t pose a problem in an adult but it is more controversial in children. On the other hand, IOL implantation has become the rule in paediatric cataract and has shown to be effective in the treatment of amblyopia."

He pointed out that IOL implantation with a good functional result in paediatric cataracts can improve neurosensoral development. Moreover, implantation of phakic refractive lenses is a reversible procedure. The refractive effect can also be adjusted by changing the IOL.

The iris-fixated Verisyse lens anterior chamber IOL may be the best option for refractive lens implantation in paediatric cases, he said. Unlike angle-supported anterior chamber IOLs and posterior chamber IOLs its stability is independent of ocular growth.

Furthermore the lens can correct a high degree of ametropia. Follow-up studies in adults implanted with the lens for over 15 years have shown the procedure to be safe over the long-term. However, endothelial risk remains a concern and the procedure should be restricted to those cases where conventional approaches have failed.

Dr Bosc noted that at his own centre he now implants the Verisyse lens in paediatric patients with recurrent refractive amblyopia who are contact lens intolerant. He strictly adheres to the follow-up treatment of amblyopia with patch occlusion.

"This is not only refractive surgery, it is surgery for amblyopia. The treatment of amblyopia must be continued. "

For a child to be suitable for the procedure cooperation is imperative for both examination and amblyopia treatment. He excludes patients if he cannot perform specular microscopy.

The surgical procedure he uses is not different from that which he uses in adults. He calculates the lens power by measuring cycloplaegic refraction with an autorefractor. He uses general anaesthesia and he noted that the enclavation of the iris in paediatric patients does not pose any particular difficulty, but it must include enough tissue.

In a series of 14 eyes of 10 patients with a follow-up of over two years nearly all had an improvement in BCVA at two years follow-up. In addition, all patients reported an improvement in daily activities especially in school and in sport. Furthermore, endothelial cell loss after surgery was only 5% and did not increase during the follow-up period.

He pointed out that there was a great improvement in visual acuity in patients with high bilateral myopia. In one case, a young girl five years of age who was contact lens intolerant, BCVA improved from counting fingers to 0.4 and 0.6 with a small correction.

"The use of the iris claw Verisyse lens in management of refractive amblyopia shows very encouraging results although we need to have a follow-up with endothelial cell counts. We are very happy with the results in bilateral high myopia and we will be using the toric Verisyse lens for amblyopic patients with high astigmatism."

The toric Verisyse
Dr Dick told the symposium that the AMO toric Verisyse lens provides the refractive surgeon with a greater potential for the individualised treatment of astigmatism than any other refractive IOL currently available.

The toric Verisyse has 5.0 mm optic and an overall diameter of 8.5 mm. It has a spherical anterior surface and a toric posterior surface. The lens powers available range from -3.0 D to -20 D for myopic correction from +2 D to + 12 D for hyperopic corrections. The cylindrical powers range from 2.0 D to 7.5 D in 0.5 D steps.
There are two models on the market. One is for eyes with an axis of astigmatism between zero and 45º or 135º to 180º, and the other is for eyes with an axis of astigmatism between 45º and 135º. The axis of cylinder is perpendicular to the axis of the claws that is model B.

In a European multicentre study, two-thirds of 70 eyes implanted with the Verisyse IOL gained one or more lines of BCVA, 53% had a UCVA of 0.8 or better and 90% had an uncorrected visual acuity of 0.5 or better at six months follow-up.

Furthermore, while many patients had a high degree of preoperative astigmatism (range: 0.5 D to 7.0 D) postoperative astigmatism was 1.0 D or less in nearly all cases and no eyes had a postoperative cylinder greater than 2.0 D.

"The efficacy index was 1.05 and 100% achieved a postoperative UCVA that was better than their pre-operative BSCVA and that is something we may never be able to achieve with corneal ablative procedures."

There were no sight-threatening complications and only one additional surgical manoeuvre, where a suture had to be placed.

"The toric Verisyse lens is a safe efficient and stable new surgical option with a very high predictability concerning both refraction and astigmatism resulting in a very high patient satisfaction."

A challenging case
Dr Dick described to the symposium how the toric Verisyse lens proved extremely versatile in a particularly challenging case.

A colleague referred to his centre a young female patient who had an unsatisfactory postoperative outcome after implantation of a toric Verisyse lens. The patient, an ophthalmic nurse, had requested the procedure for the correction of hyperopia and astigmatism. Postoperatively, the patient complained of decreased visual acuity and blurred vision with spectacle correction.

The surgeon who implanted the lens thought he missed the target axis. However, when he re-dialled the lens seven degrees the outcome did not improve and the patient was left with a UCVA of 20/60 and a BCVA 20/20.

Careful examination had ruled out all of the usual causes of an unsatisfactory outcome. The IOL was well-centred, the patient had a calm anterior segment, and there was no inflammation or macular changes and the patient had no orthoptic pathology.

Furthermore, there were no clinically relevant topographical changes compared to preoperative measurements and there was no irregular astigmatism which might have explained blurred vision. However, aberrometry showed that the patient had 1.0 D of hyperopia with 3.0 D of astigmatism and very high coma of 1.3 microns, postoperatively.

What ultimately revealed the nature of the problem was an assessment of the eye with the IOLMaster. The IOLMaster not only provides the white-to-white measurements but also determines the line of sight. In this patient the line of sight was decentred nasally and inferiorly, which is not uncommon in hyperopic eyes.

"This was a case where we had to displace and individualise this lens and this is an option only the Verisyse offers. So we re-enclavated a little bit nasally and inferiorly bringing the centre of the lens closer to the line of sight and that solved the problem. The patient came out with an uncorrected visual acuity of 20/20 the coma decreased by 400% and she was very happy."

Other phakic refractive lenses currently available could not be customised for a patient with a decentred line of sight. Their haptics do not allow adjustable centration without causing harm to intraocular structures or impairing the optical function of the lens.

"To my knowledge the Verisyse is the only phakic IOL at the moment that allows individualised solutions."

Bioptics
Erik Mertens MD told the symposium that combining Lasik with refractive lens implantation can enhance the benefits of both procedures and overcome their limitations.

He noted that refractive corneal surgery is limited to the treatment of myopia up to - 10 D and for hyperopia up to + 4.0 D. Refractive IOLs such as the Verisyse lens can correct up to -25 D of myopia and up to +12 D of hyperopia. Using Lasik as a secondary procedure for the correction of residual ametropia in patients implanted with such lenses can increase the accuracy of refractive surgery in high ametropes, Dr Mertens said.

To illustrate the potential benefits of a bioptic approach Dr Mertens presented the results of a retrospective study involving 159 eyes of patients who underwent implantation of Verisyse lens followed by Lasik to correct high ametropia.

The study included 134 eyes with myopia ranging from -8.0 D to –26 D and 25 eyes with hyperopia ranging from +4.5 D to +12 D. At four years follow-up, 93% gained at least one line of BSCVA and 77% gained two or more lines. Those gaining two or more lines included 115 (85%) myopes and seven (28%) hyperopes.

Moreover, refraction stabilised after two months and remained stable throughout the follow-up period.

All involved in the study had an anterior chamber depth of at least 3.2mm. In eyes with a myopic error less than -15.5 D, Dr Mertens implanted the 6.0 mm optic model of the Verisyse lens. In those with a myopic error greater than -15.5 D and in hyperopes, he implanted the 5.0mm optic model. For the corneal ablations he used the Bausch and Lomb Technolas 2172 excimer laser.

All patients underwent YAG laser iridotomy at least one week before implanting the Verisyse lens. Prior to surgery Dr Mertens applied topical anaesthesia. He then marked the centre of the cornea with a Sinskey hook and created two small paracenteses.

Dr Mertens then induced miosis and injected a high viscosity visoelastic. He then inserted the lens through a corneal incision. For enclavation of the iris he used two different methods. One involved using a needle to push the iris up between the claws of the lens. The other method involved holding the iris in place and pulling the lens down.

Once the lens is in place he flushed out the viscoelastic and closed the wound with one or two 10-0 sutures. He then applied one drop of atropine 1% and antibiotic drops. Patients received a tapering regimen of steroids for four weeks. In hyperopes he maintained cycloplaegia for one week to avoid posterior synechiae.

Dr Mertens removed sutures three weeks after IOL implantation. He measured their refraction three weeks after suture removal. Two weeks later, if refraction was stable and there was residual ametropia, he performed Lasik.

He used the Hansatome microkeratome with a 180 or 160 micron depth plate and an 8.5mm or 9.5mm ring plate to create the flaps. He noted that it was originally his practice to first create the flap and then implant the lens. He felt that this sequence would lower the risk of touching the corneal endothelium during the microkeratome pass.

However, he now waits until the patient’s final refraction after refractive lens implantation before creating the flap as many patients do not require a second procedure. In addition, the zero compression head of the newer model of the Hansatome safely maintains the distance between the implanted refractive lens and corneal endothelium during flap creation.

The complications included one case of mild bleeding after YAG iridotomy and 17 cases of corneal erosion, all of which occurred before the introduction of the zero compression head. One patient had pupillary block glaucoma which probably resulted from viscoelastic blocking the iridotomy. In addition there was one case of overcorrection and three cases of flap dislocation.

"Bioptics using the Verisyse lens and Lasik was successful in the treatment of high ametropia with acceptable rates of stability and safety and optical quality improvement, but with an increased surgical risk. I think we are moving more and more to phakic IOL implantation without consecutive Lasik even for lower ametropia."

Thicker flaps are safer
Alessandro Mularoni MD told the conference that a microkeratome which provides reliable thick flaps can prevent the majority of flap complications, including button-holes, striae, and flap cracks. The thicker flaps are also easier to manipulate which improves the speed and efficiency of surgery, he said.

As the current guidelines for Lasik restrict the procedure to the correction of low-to-moderate ametropia, most patients treated with the technique will have a residual stromal bed within the recommended limit at least 250 microns even when they have fairly thick flaps. Therefore, thick flaps generally will not increase the risk of ectasia.

Dr Mularoni noted that the Amadeus microkeratome from AMO is ideal for creating thick flaps. It also has several other advantageous features for the surgeon, including programmable parameters and computerised security checking. Furthermore, the microkeratome can be assembled away from the eye and provides the option of a nasal or superior flap hinge.

In the first 100 cases in which he used the Amadeus microkeratome there were no free caps, incomplete flaps, button-holes or flap striae, he noted. Furthermore, intraoperative pachymetry showed that flap thickness was predictable at a mean of 159 microns (range: 115-205 microns), using a 160 microns blade holder.

The patients in the study included 48 men and 52 women with a mean age of 41 years (range 25-59 years). The mean preoperative spherical refraction was -6.63 D (range: -1.5 D to -10.5 D) among 84 myopic eyes and +4.64 (range: +1.5 to +6.0) among 16 hyperopic eyes. Their preoperative mean central corneal thickness, measured by ORBSCAN and ultrasound, was 563 microns (range: 500-638 microns).

Dr Mularoni used 600mmHg of vacuum with a 9.5mm or 8.5mm suction ring. He set the blade oscillation rate at 13,000 rpm and the blade advancement rate at 3.0mm/sec. He used a 160 micron depth plate and aimed at a hinge width of 0.6-1.0mm with a nasal hinge position. For the corneal ablation he used the custom ablation (CIPTA) using the Lasersight LSX flying-spot excimer laser.

Complications included one case of epithelial defect, four cases of limbal bleeding and three cases of diffuse lamellar keratitis, all of which occurred in eyes with limbal bleeding. Dr Mularoni noted that the 8.5 suction ring may be safer in eyes with a white-to-white measurement shorter than 10.6mm.

"The Amadeus is a safe and easy-to-use microkeratome. It produces smooth flap edges, predictable Flap thickness and a good quality of stromal bed. There were few complications and using the nasal hinge may reduce the incidence of postoperative problems of dry eye.