Fig. 27.1
Scanning electron microscopy (SEM) of ARTIFLEX pIOL
It has a flexible optic with a diameter of 6 mm. The total diameter of the lens is 8.5 mm and the maximum width of the haptics is 3 mm (Fig. 27.2 and Table 27.1), so that it can be inserted through a small incision (3.2 mm), with the benefits this entails.
Fig. 27.2
Lens design
Table 27.1
Properties of ARTIFLEX toric pIOL
Optic material | Claw material | Overall Ø | Body Ø | Edge design | Refractive index |
|---|---|---|---|---|---|
Hydrophobic Polysiloxane | PMMA CQ-UV | 8.5 mm | 6.0 mm | Polynomial | 1.43 |
This pIOL is available with a 0° or a 90° cylinder. This enables implantation of the Toric PIOL in a horizontal or slightly oblique position through a 12 o’clock incision, as well as in a more or less vertical position through a temporal incision. Essentially no change in the surgeon’s implantation technique is required. The iris fixation method ensures exact positioning on the cylinder axis, without risk of lens rotation or decentration (Fig. 27.3).
Fig. 27.3
ARTIFLEX anterior chamber iris claw pIOL
Its concave–convex shape makes the distance between the peripheral margin of the optic and the corneal endothelium constant regardless of the dioptric power. In addition, this also enables a separation of 1.18 mm anterior to the iris plane, which facilitates normal aqueous flow, thus preventing a pupillary block (although it is advisable to perform iridotomy). Its insertion is done through a specially designed spatula.
The ARTISAN ® toric pIOL is designed for the correction of astigmatism in combination with myopia or hyperopia. The asymmetric optic has two components: sphere and cylinder. All (spherical) ARTISAN lenses for myopia and hyperopia can be supplied with cylinders between 1 and 7.5 diopters. It is also possible to supply optics with only a cylindric correction (Table 27.2).
Table 27.2
Properties of ARTISAN® toric pIOL
Material | Overall Ø | Body Ø | Availability |
|---|---|---|---|
Perspex CQ-UV | 8.5 mm | 5.0 mm|concave–convex | Can correct astigmatism from 1 to 7.5 diopters |
The ARTISAN pIOL shows in cross-section a low profile within the eye. The distance from the edge of the optic to the corneal endothelium is approximately >1.0 mm, depending on the anterior chamber depth and the dioptric power.
This lens is biconcave and made of poly (methyl methacrylate) with an ultraviolet-absorbing Perspex material. It has an overall 8.5 mm diameter, 5.0 mm lens width, 5.0 mm optic zone, 1.04 mm height, and a 0.93 mm thickness (Fig. 27.4).
Fig. 27.4
ARTISAN anterior chamber iris claw pIOL
The Artisan toric PIOL has two models. Model A has a 0° cylinder axis corresponding to the main lens axis, which runs through the claws. This model is implanted in cases where the cylinder axis to be corrected is between 0° and 45° or in cases with astigmatic meridians between 135° and 180° if the surgeon prefers a superior approach. Model B has its cylinder axis at 90°, perpendicular to the main lens axis, which runs through the claws. It is implanted when the cylinder axis to be corrected is between 45° and 135° if the surgeon prefers a superior approach. When performing a temporal approach, the previous two models could be used but in the reversed manner—model A for correction of astigmatism between 45° and 135° and model B for correction of astigmatism between 0° and 45° or in cases with astigmatic meridians between 135° and 180° (Tables 27.3 and 27.4).
Table 27.3
Dioptric powers (positive cylinder range)
Positive cylinder range | |||
|---|---|---|---|
Cylinder power | Minimal sphere power | Maximal sphere power | Sphere power increments |
1 | −23.0 | 6.5 | 0.5 |
1.5 | −23.0 | 6.5 | 0.5 |
2 | −23.0 | 6.5 | 0.5 |
2.5 | −23.0 | 6.5 | 0.5 |
3 | −23.0 | 6.5 | 0.5 |
3.5 | −23.0 | 6.5 | 0.5 |
4 | −23.0 | 6.5 | 0.5 |
4.5 | −23.0 | 6.5 | 0.5 |
5 | −23.0 | 6.5 | 0.5 |
5.5 | −23.0 | 6.5 | 0.5 |
6 | −23.0 | 6.5 | 0.5 |
6.5 | −23.0 | 6.5 | 0.5 |
7 | −23.0 | 6.5 | 0.5 |
7.5 | −23.0 | 6.5 | 0.5 |
Table 27.4
Dioptric powers (negative cylinder range)
Negative cylinder range | |||
|---|---|---|---|
Cylinder power | Minimal sphere power | Maximal sphere power | Sphere power increments |
−1 | −22 | 7.5 | 0.5 |
−1.5 | −21.5 | 8 | 0.5 |
−2 | −21 | 8.5 | 0.5 |
−2.5 | −20.5 | 9 | 0.5 |
−3 | −20 | 9.5 | 0.5 |
−3.5 | −19.5 | 10 | 0.5 |
−4 | −19 | 10.5 | 0.5 |
−4.5 | −18.5 | 11 | 0.5 |
−5 | −18 | 11.5 | 0.5 |
−5.5 | −17.5 | 12 | 0.5 |
−6 | −17 | 12.5 | 0.5 |
−6.5 | −16.5 | 13 | 0.5 |
−7 | −16 | 13.5 | 0.5 |
−7.5 | −15.5 | 14 | 0.5 |
27.3 Surgical Technique
The surgical technique is similar to the nontoric pIOLs , except for the need to fixate the lens on a precise axis. Preoperative determination and marking of the cylinder axis is therefore essential for an optimal refractive correction.
The incision width required for implantation of the lens is 5.5 mm for the ARTISAN toric lens, and 3.2 mm for the ARTIFLEX toric lens. This incision should be perpendicular to the enclavation axis.
Being cases of keratoconus, which are characterized by a destabilized corneal geometry , we propose to perform a tunneled scleral incision because an incision in the corneal area could lead to a weakening of the corneal tissue and unpredictable astigmatic change (Fig. 27.5) favoring even more the process of instability present in the irregular cornea.
