Neel Dave Pasricha, MD and Ayman Naseri, MD
The anterior chamber intraocular lens (ACIOL) has been in use since the 1950s. Early ACIOL models were rigid and were used primarily with intracapsular cataract extraction and extracapsular cataract extraction. Complications were common with early versions of the ACIOL, and included pseudophakic bullous keratopathy, glaucoma, and cystoid macular edema.1,2 The next generation included flexible, closed-loop ACIOLs, which unfortunately still suffered from high rates of complications, especially pseudophakic bullous keratopathy and uveitis-glaucoma-hyphema syndrome.3–5 Fortunately, with the development of flexible, open-loop ACIOLs, modern ACIOL implantation now enjoys high success rates with a substantial reduction in complications compared to prior ACIOL models.6,7 This technology warrants consideration from any cataract surgeon practicing in the 21st century.
One of the attractive advantages of ACIOL implantation in cases of deficient capsular support is its simplicity, allowing comprehensive ophthalmologists to comfortably and safely place them into the anterior chamber without requiring subspecialty training or a surgical assistant.8 Also, unlike glued IOLs or scleral-fixated IOLs, ACIOLs avoid glue-associated complications such as lens decentration or suture-related complications such as suture erosion and late dislocation.9–11 Additionally, since insertion is technically straightforward, ACIOL insertion can be done relatively quickly, and thus reduce potential complications associated with longer operative times such as retinal phototoxicity.7,12,13
Types of Anterior Chamber IOLs
ANGLE-SUPPORTED ANTERIOR CHAMBER IOLS
The Kelman Multiflex III (Alcon Laboratories, Inc) has been in use since the 1980s. It is made of polymethylmethacrylate (PMMA). The optic diameter is 5.5 mm and is connected to 2 flexible haptics that together provide 4-point fixation in the anterior chamber angle. In order to prevent pupillary block, the haptics vault the optic 0.5 mm anteriorly. Total lens length ranges from 12.0 to 14.5 mm and needs to be sized roughly 1.0 mm longer than the horizontal corneal white-to-white measurement. Dioptric power ranges from +5.0 to +30.0 diopters (D). A large study in Nepal compared patients undergoing intracapsular cataract extraction with aphakic correction vs Kelman Multiflex III ACIOL implantation and concluded ACIOL implantation is safe, with only 2.6% of patients experiencing a poor visual outcome, defined as best corrected visual acuity (BCVA) worse than 6/60, at 1-year follow-up. Uveitis was the most common reason for poor visual outcome, and almost half of the patients with uveitis and poor visual outcome at postoperative year 1 had improved visual outcomes after 1 additional year.6
Figure 53-1. Schematic of the Kelman Multiflex III ACIOL. Note the convex-plano design of the optic. The 2 attached haptics provide 4-point fixation in the anterior chamber angle. (Reprinted with permission from Alcon Laboratories, Inc.)
Another angle-supported ACIOL is the 122UV (Bausch + Lomb), which comes in 2 lengths: S122UV (12.5 mm) and L122UV (13.5 mm). Both are made of rigid PMMA and have 6.0-mm optics attached to 2 haptics that together provide 4-point fixation in the anterior chamber angle and anteriorly vault the lens, similar to the Kelman Multiflex III. The distinguishing feature between these angle-supported ACIOLs is the convex-plano design of the Kelman Multiflex III ACIOL (Figure 53-1) compared to the biconvex design of the 122UV (Figure 53-2). Dioptric power ranges are +10.0 D to +30.0 D for the S122UV and +5.0 D to +30.0 D for the L122UV. One study compared angle-supported ACIOL implantation with either the Kelman Multiflex III ACIOL or the L122UV in aphakic patients with poor capsular support who had a history of chronic uveitis in remission vs no history of uveitis and found no difference in long-term complications up until 5 years of follow-up between the 2 groups. The fact that both groups fared reasonably well suggests that a history of uveitis alone may not be a contraindication to angle-supported ACIOL implantation.14
IRIS CLAW ANTERIOR CHAMBER IOLS
As of 2017, only angle-supported ACIOLs are approved for aphakia correction in the United States.15 However, US Food and Drug Administration trials on iris claw ACIOLs are in Phase 3 for the treatment of aphakia in both children and adults.
The Artisan lens (Ophtec BV) has been in use since the 1970s. This lens is made of rigid PMMA and consists of a 5.0-mm optic attached to 2 haptic iris claws for iris fixation (Figure 53-3). The standard total length is 8.5 mm and, since it is not angle supported, there is no sizing necessary in most patients. However, smaller length 7.5- and 6.5-mm lenses are also available if needed. This one-size-fits-all feature of iris claw ACIOLs makes stocking of various sizes a nonissue and makes it an attractive option in cases with uncommon angle and anterior segment dimensions, such as in patients with megalocornea.16,17 Dioptric power ranges from +2.0 D to +30.0 D. The lens is fixed to the iris via iris enclavation using a needle, forceps, or vacuum technique. Postoperative outcomes are similar for anterior chamber vs retropupillary implantation of iris claw ACIOLs.18
Figure 53-2. Schematic of the S122UV. (Reprinted with permission from Bausch + Lomb.)
Iris claw ACIOLs to correct aphakia in patients with poor capsular support achieve excellent uncorrected distance visual acuity (UDVA), with one study demonstrating 73.6% of patients reaching 20/40 or better.19 The visual acuity improvement also has shown excellent long-term stability, with BCVA and mean spherical equivalent remaining stable up until the first 5 years of follow-up.20 Intraocular pressure (IOP) postoperatively is comparable to preoperative levels.19 There is a slight progressive endothelial cell loss after iris claw ACIOL implantation. However, by postoperative year 2, the endothelial morphometric changes recover to near preoperative levels, indicating that endothelial cell damage occurred primarily during the surgery itself and was not associated with progressive ongoing loss.21 Comparing iris claw ACIOL vs scleral-sutured posterior chamber IOL (PCIOL) after vitrectomy and lens extraction without adequate capsular support shows comparable long-term BCVA and IOP, but more rapid initial recovery of BCVA and shorter surgical duration with iris claw ACIOL.22
FOLDABLE ANTERIOR CHAMBER IOLS
Current ACIOL models are not foldable and thus require an incision ranging from 6.0 to 7.0 mm wide for insertion into the anterior chamber. A new ACIOL, Acri.Lyc 15A (Acritec), is a foldable acrylic and allows for insertion through a 2.8-mm-wide incision. One case series found minor complications following implantation of the Acri.Lyc 15A including corneal edema, Descemet folds, increased IOP, hyphema, distorted pupil shape, iris bombe, vitreous hemorrhage, displaced ACIOL, and cystoid macular edema.23 These minor complications did not influence final results, which demonstrated a statistically significant increase in postoperative BCVA compared to preoperative BCVA.23
Figure 53-3. Image of the Artisan iris claw ACIOL. The optic is attached to 2 haptic iris claws to allow for iris fixation. (Reprinted with permission from Ophtec BV.)
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