Alio reported on 69 eyes of 52 patients implanted with the Acri.LISA 366D and found good efficacy and safety, good predictability, and excellent distance and near visual acuity . Distance-corrected near acuity averaged 0.90 ± 0.14 (between 20/20 and 20/25). This study also evaluated the intraocular performance and demonstrated good intraocular aberration, Strehl ratio, and MTF values [3].

The latest addition to the Acri.Tec inventory of microincision IOLs is the Acri.LISAtoric 466TD. This lens has a diffractive bifocal aspheric front surface and a toric aspheric back surface. Similar to the Acri.LISA bifocal IOL, the Acri.LISAtoric distributes 65% of incident light for distance focus and 35% for near focus, functions independent of pupil size, and incorporates a 3.75 D add that corresponds to a +3.00 D add at the spectacle plane. The advantage of this IOL is the ability to correct large amounts of cylinder at the time of implantation of the bifocal optic, which would improve final visual acuities relative to procedures that require large limbal relaxing incisions for astigmatic reduction. The rotational stability of the Acri.Tec single-piece plate lenses has been demonstrated to be excellent with Reiter [23] reporting less than 4° of rotation in 98% of eyes at 6 months follow-up and Wehner [32] reporting no rotation or decentration of the Acri.Smart IOL, 12–19 months postoperatively. Thus, the capacity to stably correct up to +12 D of cylinder while simultaneously implanting a high quality bifocal IOL would make this lens a popular option for presbyopia correction in the future.

Breyer recently reported early results of ten bilateral implantations in 5 patients which included eyes with high astigmatism and myopia. At the 5 month follow-up, mean spherical equivalent improved from −5.25 to 0.4 D and the mean cylinder improved from 2.25 to 0.44 D. Uncorrected mean postoperative acuity was 0.69 (approximately 20/30) for distance and 0.78 (approximately 20/25) for near [19].

8.3.5.5Akreos

The Bausch & Lomb Akreos AO MI60 (Fig. 8.62) is one of the several IOLs in the Akreos inventory that can be injected through a 1.8 mm incision. The Akreos IOLs are one-piece equiconvex hydrophilic acrylic lenses made from a poly-HEMA/MMA copolymer.

The Akreos AO MI60 has a thin, aspherical, aberra- tion-free optic with a 360° posterior square edge to reduce PCO. The lens has four haptics that provide for four-point fixation while stabilizing the optic in three dimensions. This transpires by virtue of conforming tips at the end of each haptic that are able to bend as the capsular bag contracts and avoid transferring these contraction forces to the optic (Fig. 8.63). A 10° angulation of the haptics enhances the contact of the optic

Fig. 8.62 Bausch & Lomb Akreos AO MI60 (Courtesy of Bausch & Lomb)

Fig. 8.63 Conforming tips at the end of each haptic of the Akreos AO MI60 bend as the capsular bag contracts to avoid transferring contraction forces to the optic

with the posterior capsule to further reduce the development of PCO [4].

The Akreos AO MI60 is available in powers ranging from +10.0 to +30.0 D. In order to maximize stability of the IOL and posterior edge contact, regardless of the capsular bag size, the IOL is manufactured in three different diameters with three optic sizes depending on the lens power. For IOL powers between 10 and 15 D, the overall diameter is 11.0 mm with an optic diameter of 6.2 mm. For powers between 15.5 and 22.0 D, the overall diameter is 10.7 mm with an optic diameter of 6.0 mm. For higher powered IOLs of 22.5 D and greater, the overall diameter decreases to 10.5 mm with an optic diameter of 5.6 mm [4].

Hydrophilic acrylic IOLs have a higher water content and lower refractive index than hydrophobic acrylic IOLs. This may result in fewer problems with postoperative glare, external and internal reflections, and other unwanted dysphotopsias. A study comparing the Akreos with the AcrySof SN60-AT demonstrated fewer reported negative dysphotopsia complaints in the Akreos patients 1 week following surgery. However, 8 weeks following surgery, although there remained some differences between the two groups, they were not statistically significant [22]. A study comparing the Akreos AO with the Tecnis Z9000 implanted in each eye of 80 patients demonstrated that 33% of patients reported more visual disturbances with the Tecnis lens compared to 11% with the Akreos. In addition, the study revealed better patient satisfaction with the Akreos IOL with 28% reporting better subjective visual quality with the Akreos compared to 14% in the Tecnis eye. The Akreos IOL was found to provide a larger depth of field than the Tecnis lens which may have been partially responsible for the perceived higher quality of vision [10].

Although some surgeons are implanting the Akreos AO MI60 through incision sizes of 1.5–1.7 mm, Murta recommends an incision size of 1.8 mm and found that with this incision size, the mean amount of incision stretch was only 0.09 mm when a wound-assisted injection technique was performed [16] (Fig. 8.64). In a small 40-patient study he found that the IOL exhibited excellent biocompatibility, stability, and no evidence of surface deposition was noted (Fig. 8.65). One potential drawback of the Akreos 4 haptic IOL is the possibility of a rare but increased incidence of capsular block syndrome [13].

Fig. 8.64 Wound-assisted injection of Akreos AO MI60 through an incision size of 1.8 mm. The mean amount of incision stretch was 0.09 mm. (Courtesy of Joaquin Murta)

Fig. 8.65 Akreos AO MI60 in situ (Courtesy of Joaquin Murta)

8.3.5.6Tetraflex

The Lenstec Kellan Tetraflex (model KH-3500) is a poly-HEMA accommodating IOL that can be injected through a 2 mm incision using a 1.8 mm cartridge system. The IOL has a square-edge design with a 5.75 mm optic (Fig. 8.66). The lens is designed to angulate forward, away from the posterior capsule in the resting state. In contrast to hinged-accommodating IOLs, the Tetraflex has no hinges and has a unique mechanism of accommodation that does not depend on vitreous pressure during accommodative effort. The haptic design of the IOL are proposed to allow the lens to move forward with the capsular bag during accommodation [12].

Fig. 8.66 The Lenstec Kellan

Tetraflex (model KH-3500)

Sanders reported on 95 eyes of 59 patients implanted with the tetraflex. Six months following surgery, 63% of the eyes had a distance-corrected near acuity of 20/40, or better. Of the patients who were implanted bilaterally, all the patients were reported to have achieved 1 D of accommodative ability and 96% had at least 2 D [25]. In a separate paper, Sanders found that 88% of the Tetraflex eyes obtained distance corrected near acuities that were sufficient to read a newspaper and telephone directory print and 63% could read classified ads, stock quotes, and pocket bibles. When tested binocularly, these percentages increased to 96 and 89% [26]. The prospects of an accommodating IOL that yields good functional near vision in a large majority of patients, while being implantable through an incision of 2 mm holds great promise. Further studies and research will be needed to confirm the viability and efficacy of this IOL.

8.3.5.7Rayner

Rayner Intraocular Lenses (East Sussex, England) has a vast inventory of lenses that can be injected through their single use soft-tipped IOL injector (R-INJ-04). The injector has an outer nozzle tip diameter of 2.0 mm and the company claims that their lenses can be injected through a sub 2.0 mm incision utilizing a woundassisted injection technique. Regardless of the minimal incision size that these IOLs can be inserted through, they do have special qualities that deserve mention.

Fig. 8.67 Angled view of the Raynor C-flex (570C) IOL demonstrating the unique AVH technology (Photo courtesy of Rayner)

The two major classes of foldable IOLs that Rayner produces are designed for in-the-bag and sulcus implantation. The in-the-bag IOLs include the C-flex, Superflex®, T-flex®, M-flex®, and M-flex® T lenses. The lenses designed for sulcus implantation include the Sulcoflex® Aspheric, Sulcoflex® Toric, and Sulcoflex® Multifocal IOLs.

All of the capsular bag lenses are produced on a similar lens platform that incorporates a single-piece hydrophilic acrylic design with unique anti-vaulting haptic (AVH) technology (Fig. 8.67). The AVH technology allows for capsular bag contraction to develop without affecting IOL centration, rotation, or stability within the capsular bag. The lens platform also contains the Amon-Apple Enhanced Square Edge design that features a 360° posterior square edge to the optic that includes the vulnerable optic-haptic junctions in order to reduce the incidence of PCO [5, 17, 33]. The hydrophilic acrylic material is a propriety copolymer

termed Rayacryl that has excellent biocompatibility and optical purity with no vacuoles or glistenings, in addition to low silicone oil adherence.

The C-flex IOL has an optic diameter of 5.75mm and an overall length of 12.0mm. It is available in powers between +8.0 and +30.0 D in 0.5 D increments, +30.0 to +34.0 D in 1.0 D increments, and +18.0 to +23.75 D in 0.24 D increments. In larger myopic eyes or younger patients with larger pupil diameters, the Superflex® lens has a 6.25mm optic diameter and an overall length of 12.5mm and is available in powers between −10.0 to +25.5 D in 0.5 D increments. Both the C-flex and Superflex® IOLs are also available with aberration-neutral aspheric modifications applied to the anterior surface of the IOL if asphericity of the lens is desired.

Other modifications to the capsular bag platform include a toric IOL (T-flex®), multifocal IOL (M-flex®), and combined multifocal toric IOL (M-flex® T). The excellent rotational stability offered by the AVH haptic technology makes the Rayner platform ideal for a toric design. The T-flex® has the toric component implemented on the anterior surface of the optic and is available in two models. Model 623T has a 6.25 mm optic and is designed for low and medium power lenses and model 573T contains a 5.75 mm optic and is designed for higher power lenses. The standard lenses are available with powers ranging from +6.0 to +26.0 D in 0.5 D incremental steps with +1.0 to +6.0 D of cylindrical correction in 1.0 D increments. Alternative powers are also available with −10.0 to +35.0 D with up to +11.0 D of cylindrical correction in 0.25 D increments.

The Rayner M-flex® is a multi-zoned refractive aspheric IOL with either four or five annular zones (depending on IOL base power) that are available with either +3.0 or +4.0 D of additional near power (equivalent to +2.25 or +3.0 D respectively at the spectacle plane). These alternate near powers give the option of the same power bilateral implantation or “mix and match” implantation, utilizing the same IOL multifocal design platform with two different adds. The M-flex® optic incorporates multi-aspheric aberration-neutral surfaces with the interface between each annular zone designed to reduce halo and glare. At each zonal interface, the aspheric correction is adjusted and the aspheric coefficients are recalculated to create a precise zonal blend. This lens contains a 6.25 mm optic with an overall length of 12.5 mm. The powers range from +14.0 to +25.0 D in 1.0 D increments and +18.5 to +23.5 D in 0.5 D increments, for both add powers.

Although limbal relaxing incisions can be performed at the time of multifocal IOL implantation to reduce or eliminate preexisting astigmatism, the ideal multifocal IOLs of the future will have toric corrections combined with multifocality on one platform. The Rayner M-flex® T combines all of the features of the M-Flex and T-flex lenses in one IOL model. It is available in two optic sizes of 5.75 and 6.25 mm with either a +3.0 or +4.0 D add. The standard power range is +14.0 to +32.0 D in 0.5 D increments with a 2.0 D cylinder add and toric corrections of 1.0–6.0 D in 0.5 D increments can also be ordered.

One of the more exciting technologies recently released by Rayner include their pseudophakic supplementary IOLs designed to eliminate postoperative refractive errors by means of ciliary sulcus piggy-back IOL implantation. Unlike conventional piggy-back IOLs, the Rayner Sulcoflex® lenses have a unique concave posterior surface that avoids physical contact between the two IOLs. This would reduce the likelihood of optic surface distortion, unwanted photopic effects, and hyperopic defocus. The wide 6.5 mm roundedged optic and undulating round-edged haptics with 10° angulation (Fig. 8.68) would reduce the risk of dysphotopsias, optic-iris capture, and uveal contact with pigment dispersion, while providing excellent centration and rotational stability.

The Sulcoflex platform comes in an aspheric model, toric model, and multifocal model. These models allow the surgeon to adjust postoperative spherical errors with the Sulcoflex® Aspheric (653L) and postoperative residual cylinder with the Sulcoflex® Toric (653T) (Fig. 8.69), and also allows currently, monofocal pseudophakic patients, the opportunity to attempt to correct their pseudophakic presbyopia with a Sulcoflex® Multifocal IOL (653F) (Fig. 8.70). If a patient is dissatisfied with the quality of the toric or multifocal optics, the sulcus lens can be easily explanted.

The Sulcoflex® Aspheric IOL comes available in powers −10.0 to +10.0 D in 0.5 D increments. The Sulcoflex Multifocal comes available in powers from −5.0 to +5.0 D in 0.5 D increments and a +3.50 D add. The Sulcoflex® Toric is available in spherical powers between −9.0 and +3.0 D and with cyclindrical powers from 1.0 to 6.0 D in 0.5 D increments.

Over all, the Rayner inventory of foldable hydrophilic acrylic capsular bag and sulcus lenses encompasses an exciting array of choices, for enhancing patient outcomes immediately, and several years