Allon Barsam, MA, FRCOphth and Soyang Ella Kim, MBBS, MA (Oxon), PG Cert
The Sulcoflex intraocular lens (IOL) was specifically designed for implantation in the ciliary sulcus as a secondary supplementary lens. It is used in pseudophakic eyes to address a postoperative refractive surprise, residual corneal astigmatism,1,2 and presbyopia.3 It was developed by Rayner Intraocular Lenses Ltd to overcome problems encountered with conventional piggyback lenses.
Despite advances in biometry techniques and IOL power calculations, pseudophakic refractive errors are not always avoidable. With increasingly greater patient demand for near-perfect visual and refractive outcomes, enhancement strategies, such as secondary piggyback IOLs, have become popular. Conventional piggyback lenses have been implanted into the capsular bag to overcome refractive surprises, but these have been associated with a range of complications such as interlenticular opacification and contact-induced central flattening of the primary IOL.4–6
The Sulcoflex IOL has several design features to overcome these problems of conventional secondary supplementary lenses. It can also be implanted alone without an intracapsular primary IOL, especially when capsular fixation is not possible. However, because the Sulcoflex IOL was designed as a secondary IOL, the range of available dioptric powers is much lower than with standard primary IOLs. This limits this option of primary implantation to eyes requiring low IOL powers.
Indications of the Sulcoflex IOL include the following:
- Correction of postsurgical ametropia
- Enhancement of result of refractive lens exchange
- Enhancement of near, intermediate, or distance vision
- Correction of residual corneal astigmatism
- Correction of refractive changes following pediatric lens implantation
- Sulcus fixation when intracapsular fixation is not possible
Secondary IOLs Compared to Other Options
There are several different surgical options for treating pseudophakic ametropia, including lens exchange, implantation of a secondary piggyback IOL, and keratorefractive laser surgery. The advantages of secondary piggyback IOL implantation over IOL exchange are better refractive predictability, safer surgical technique, and less trauma.7,8 It is also a good alternative to laser enhancements where corneal surgery is not accessible or advisable. Examples would include patients who have had previous corneal surgery or if the corneal surface is of poor quality, such as with severe dry eye.
As the name suggests, the Sulcoflex IOL has been designed for implantation in the ciliary sulcus, and we will highlight those features that differentiate the Sulcoflex from conventional piggyback IOLs that are implanted in the capsular bag.
The Sulcoflex IOL is composed of a hydrophilic acrylic co-polymer Rayacryl, which has very high uveal biocompatibility.9,10 This is important for ciliary sulcus placement of the IOL, in order to prevent adhesions to adjacent uveal structures. In addition, Rayacryl has good optical clarity with no vacuoles or glistenings. It has a refractive index of 1.46 and includes a benzophenone ultraviolet-absorbing agent with a 10% ultraviolet cut-off at 380 nm.
The Sulcoflex IOL is larger than most IOLs, with a 6.5-mm round-edged optic and 14.0-mm overall length including the haptics. The haptics are 0.33 mm in thickness, and the optic thickness is between 0.25 and 0.75 mm depending on the dioptric power.
There are a number of design features that minimize complications from sulcus placement of the IOL.
- The Sulcoflex IOL optic is shaped convex anteriorly and concave posteriorly, which improves its fit in front of the anterior convex surface of a primary IOL. Conventional piggyback lenses are usually biconvex and designed to be implanted into the capsular bag. The posterior concave surface of the Sulcoflex IOL minimizes contact with the primary biconvex IOL (Figure 19-1).
- The lens has undulating round-edged haptics that are angulated at 10 degrees so that the optic vaults slightly posteriorly relative to the haptics (Figure 19-2). This feature ensures separation from the posterior iris and minimizes risk of subsequent pigment dispersion due to iris chafe.
- The optics and haptics have soft, round edges to prevent optic-iris capture, to minimize risk of iris chafing and pigment dispersion, and to reduce edge glare and dysphotopsias (Figure 19-3).
Types of Sulcoflex Lens
SULCOFLEX ASPHERIC 653L
The Sulcoflex Aspheric IOL can be used to correct pseudophakic ametropia. It is available in the standard power range from -5.0 to +5.0 diopters (D) in increments of 0.5 D. The premium refractive IOLs are available from -10 D to +10 D, and are effective in resolving postoperative myopic and hypermetropic refractive surprises.
SULCOFLEX TORIC 653T
The Sulcoflex Toric IOL can be used to correct pseudophakic corneal astigmatism. It is an alternative to keratorefractive surgery and is available in a range of sphere/cylinder combinations. It is available in the standard range from -3.0 D to +3.0 D in increments of 0.5 D, and for premium refractive lenses, it is available in the range from -7.0 D to +7.0 D with up to 6.0 D cylindrical correction in 0.5 D increments. The undulating haptic design provides rotational stability for precise toric alignment.
SULCOFLEX TRIFOCAL 703F
The Sulcoflex Trifocal IOL can be used to correct pseudophakic presbyopia, significantly reducing the need for additional near and intermediate spectacle correction. Near vision is achieved by the addition of +3.5 D and intermediate vision is achieved by the addition of +1.75 D at the IOL plane in a far dominant format.