Assessment of a single-piece hydrophilic acrylic IOL for piggyback sulcus fixation in pseudophakic cadaver eyes

New Nitinol-based Thermomechanically Adjustable IOL Technology

PURPOSE

To evaluate the feasibility of new adjustable intraocular lens (IOL) technology.

METHODS

The foldable adjustable IOL consists of a nitinol mechanism placed in a haptic-optic cradle. Heating actuators on the nitinol mechanism with a continuous green laser achieve controlled movement of the mechanism and optic. Activation occurs in controlled steps: rotation in 1-degree steps over 360 degrees, and anterior posterior movement in 0.25-diopter (D) steps with a range of +1.50 D. The IOL was tested in vitro and in vivo in a rabbit eye. Foldability and unfolding were demonstrated through a 2.6-mm cartridge.

RESULTS

The adjustable lens mechanism was successfully tested in vitro and in vivo. Activation resulted in a change in optic position relative to the haptics and the capsular bag. Activation of the lever and ratchet mechanism showed radial advancement of the IOL clockwise and counterclockwise. In vivo rotatory movement was achieved after activation by the argon laser at 1 week after implantation. Anterior to posterior movement was accomplished by activating the circular spring actuator mechanism in the laboratory model. Uneventful folding and unfolding were performed.

CONCLUSIONS

A new adjustable IOL with a mechanism that responds in measured steps had been shown to move as planned after activation by argon laser. This was successful in the laboratory in both radial and anterior posterior movement. The radial movement was also proven in vivo in an animal model. Further refinement of the prototype is currently being undertaken. [J Refract Surg. 2023;39(10):662-667.].

Clinical outcomes of the piggyback secondary implantation of a novel multifocal lens in the ciliary sulcus: A case series

PURPOSE

Evaluate the clinical outcomes of the secondary piggyback add-on IOL implantation in the ciliary sulcus for pseudophakic patients previously implanted with a monofocal IOL, who pursue a spectacle-free option after IOL surgery.

METHODS

A prospective case series including seven pseudophakic patients who underwent an in-the-bag monofocal IOL implantation. All eyes underwent a piggyback IOL implantation of the new sulcus designed A4 AddOn IOL in the ciliary sulcus as a secondary procedure for pseudophakic patients pursuing a spectacle-free option for near and intermediate distance after IOL surgery.

RESULTS

Seven eyes from six patients were included in this study, from which 4 (71.43%) were female, with a mean age of 58.33 ± 3.5 years (range 54-63; 95% CI 54.66, 62.01). The postoperative spherical equivalent at the 3-month visit was -0.10 m ± 0.82. Also, the UDVA was 0.11 ± 0.08 logMAR, the UIVA 0.01 ± 0.03, and the UNVA 0.01 ± 0.03 3 months after their surgical procedure.

CONCLUSIONS

The A4 AddOn multifocal IOL's secondary piggyback implant is an efficient alternative for monofocal pseudophakic patients seeking presbyopia solutions. This sulcus-designed IOL provides an optimal visual outcome for near and distance vision.

Secondary Piggyback Intraocular Lens for Management of Residual Ametropia after Cataract Surgery

Purpose

To investigate the indications, clinical outcomes, and complications of secondary piggyback intraocular lens (IOL) implantation for correcting residual refractive error after cataract surgery.

Methods

In this prospective interventional case series, patients who had residual refractive error after cataract surgery and were candidates for secondary piggyback IOL implantation between June 2015 and September 2018 were included. All eyes underwent secondary IOL implantation with the piggyback technique in the ciliary sulcus. The types of IOLs included Sulcoflex and three-piece foldable acrylic lenses. Patients were followed-up for at least one year.

Results

Eleven patients were included. Seven patients had hyperopic ametropia, and four patients had residual myopia after cataract surgery. The preoperative mean of absolute residual refractive error was 7.20 ± 7.92, which reached 0.42 ± 1.26 postoperatively (P< 0.001). The postoperative spherical equivalent was within ±1 diopter of target refraction in all patients. The average preoperative uncorrected distance visual acuity was 1.13 ± 0.35 LogMAR, which significantly improved to 0.41 ± 0.24 LogMAR postoperatively (P = 0.008). There were no intra- or postoperative complications during the 22.4 ± 9.5 months of follow-up.

Conclusion

Secondary piggyback IOL implantation is an effective and safe technique for the correction of residual ametropia following cataract surgery. Three-piece IOLs can be safely placed as secondary piggyback IOLs in situations where specifically designed IOLs are not available.

Intraocular Lenses: Overview of Designs, Materials, and Pathophysiologic Features

This article provides an overview of intraocular lenses (IOLs) currently used in cataract surgery. Aspects presented include design features related to IOL construction and sites of fixation; optic, filter, and haptic materials; as well as pathophysiologic features of uveal biocompatibility, capsular biocompatibility, and postoperative IOL opacification. This overview also includes supplementary (add-on; piggyback) lenses implanted in eyes that are already pseudophakic and considerations on IOLs used in the pediatric population. Different IOLs are made available to surgeons each year, including lenses with increasingly complex design characteristics owing to advancements in manufacturing and surgical techniques.

Diagonal haptic capture of a plate intraocular lens with 4 haptics

A technique of diagonal haptic capture of a plate intraocular lens (IOL) with 4 haptics for cases with insufficient posterior capsular support is presented. The diagonal haptics were captured through the capsulorhexis by sequentially depressing each side of the haptic beneath the rim of the capsulorhexis with a gentle pressure. The IOL is fixated by pure IOL-capsule capture without sulcus fixation of haptics. The technique was used in 12 eyes (12 patients). The IOLs were well centered within the follow-up period. No IOL malposition, pseudophacodonesis, pupil capture, pigmental dispersion, or high intraocular tension was observed postoperatively. Ultrasound biomicroscopy revealed that there was no chafing of the IOL with the posterior iris. The technique provided an instant and definitive fixation with high adaptability to different sizes of capsulorhexis, and thereby could reduce the risk for complications related to haptic-sulcus fixation.

Outcomes of refractive error correction in pseudophakic patients using a sulcus piggyback intraocular lens

PURPOSE

The purpose of this study was to assess the results of a sulcus intraocular lens (Sulcoflex) for pseudophakic refractive errors following phacoemulsification cataract surgery.

METHODS

This retrospective clinical observational cohort study included consecutive eyes in which a Sulcoflex was implanted. Uncorrected distance visual acuity and corrected distance visual acuity as well as refractive outcomes were assessed. The minimum follow-up time required for inclusion was 3 months.

RESULTS

In total, 15 eyes (n = 15) were evaluated. The mean follow-up was 14 months (range: 3-18 months). The Sulcoflex aspheric (653L) was implanted in 13 eyes and the Sulcoflex toric (653T) in two eyes. The preoperative mean logMAR (Snellen) uncorrected distance visual acuity and corrected distance visual acuity were 0.88 (20/150) and 0.27 (20/40), respectively. The postoperative mean logMAR (Snellen) corrected distance visual acuity was 0.15 (20/30). The preoperative mean spherical equivalent was -0.22 ± 5.95 D and the postoperative mean spherical equivalent was -1.59 ± 1.45 D. There was a significant and strong correlation (r = 0.64, p < 0.001) between the attempted and the achieved spherical equivalent.

CONCLUSION

The Sulcoflex is a safe and viable option for patients with residual refractive error following cataract surgery.

Assessment of a novel pinhole supplementary implant for sulcus fixation in pseudophakic cadaver eyes

PurposeTo evaluate a novel small-aperture supplementary implant that applies the principle of pinholes for management of irregular astigmatism, in postmortem human eyes.MethodsPseudophakic human cadaver eyes were imaged by anterior segment optical coherence tomography (AS-OCT) to assess position of the in-the-bag intraocular lens (IOL). Eyes were prepared as per the Miyake-Apple technique. Two versions of the supplementary implant (open-loop and tripod designs) were then inserted into the sulcus of each eye. Evaluations under AS-OCT and from anterior and posterior views of the anterior segment were used to assess IOL fixation, centration, tilt, and interlenticular distance (ILD). This experimental study has been conducted in John A. Moran Eye Center, University of Utah.ResultsNine eyes were selected, with various sizes, primary IOL materials/designs, and Soemmering's ring formation. The open-loop model exhibited a mild degree of decentration and tilt in 2 eyes with zonular dehiscence. Mild decentration and tilt of the tripod were observed in 4 eyes; in 1 additional eye it was centered but mildly tilted. Three eyes with zonular dehiscence had one of the closed loops of the tripod located posteriorly to the ciliary processes. In all cases, an ILD was observed between the lenses (open loop: 0.65±0.13 mm; tripod: 0.41±0.12 mm).ConclusionsIt is important to take into account anatomical aspects related to ciliary sulcus fixation of supplementary IOLs. Both designs evaluated, exhibited appropriate centration and ILD. The open-loop design had less risk of tilt in association with haptics protruding posteriorly through areas of zonular weakness.

Supplementary IOLs: Monofocal and Multifocal, Their Applications and Limitations

Supplemental intraocular lenses (IOLs) have been developed to replace IOLs designed for in-the-bag placement being used as "piggy-back" IOLs in the sulcus due to unacceptable complications. The new IOLs have unique platform designs to avoid these complications. As a result, a new nomenclature is needed to describe the 4 scenarios when supplemental IOL use is now indicated.

Assessment of a new hydrophilic acrylic supplementary IOL for sulcus fixation in pseudophakic cadaver eyes

PurposeManagement of refractive errors after cataract surgery includes spectacles or contact lens, secondary laser vision correction, intraocular lens (IOL) exchange, or piggyback lens implantation. We evaluated for the first time a single-piece hydrophilic acrylic IOL designed for supplementary sulcus fixation in postmortem pseudophakic human eyes.MethodsPseudophakic human cadaver eyes were imaged by anterior segment optical coherence tomography (AS-OCT) to assess position of the primary IOL. Eyes were prepared as per the Miyake-Apple technique. The supplementary IOL (Medicontur A4 Addon IOL family) was then inserted into the ciliary sulcus. AS-OCT and photographs from anterior and posterior views were used to assess IOL centration, tilt, and interlenticular distance from the primary IOL.ResultsData were obtained from 12 eyes having primary IOLs of varying materials and designs in the bag and representing different sizes of eyes and severity of Soemmering's ring formation. The A4 Addon IOL was successfully inserted into the ciliary sulcus and was well centered in all cases. Four cases of tilt were observed on AS-OCT: three with mild tilt due to pre-existing zonular dehiscence, and one due to a localized area of Soemmering's ring formation. Interlenticular distance ranged from 0.34 to 1.24 mm and was not dependent on severity of Soemmering's ring or type of primary IOL.ConclusionsThe A4 Addon IOL was designed for sulcus fixation as a supplementary lens, with a large diameter, a square-shaped optic, four smooth loop haptics, and a convex-concave optical surface. It exhibited appropriate centration and interlenticular distance with different primary in-the-bag IOLs.

Cataract surgery in the small eye

The surgical management of cataract in the small eye presents the ophthalmic surgeon with numerous challenges. An understanding of the anatomic classification in addition to a thorough preoperative assessment will help individualize each case and enable the surgeon to better prepare for the obstacles that might be encountered during surgery. Small eyes are especially challenging in terms of intraocular lens (IOL) calculations and possible current limitations of available IOL powers, which could necessitate alternative means of achieving emmetropia. Surgical strategies for minimizing complications and maximizing good outcomes can be developed from knowledge of the anatomic differences between various small-eye conditions and the pathologies that may be associated with each. A thorough understanding of the challenges inherent in these cases and the management of intraoperative and postoperative complications will ensure that surgeons approaching the correction of these eyes will achieve the best possible surgical results.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Calcification of hydrophilic acrylic intraocular lenses associated with intracameral air injection following DMEK

We present 2 cases of localized calcification on the anterior surface/subsurface of hydrophilic acrylic intraocular lenses (IOLs) following procedures involving intracameral injection of air. Although this phenomenon has been reported in hydrophilic acrylic IOLs, to our knowledge it has not been reported in the IOLs described in our cases, one a sulcus-fixated supplementary IOL and the other a hydrophilic acrylic IOL with a hydrophobic surface. Centralized opacity of the IOLs was first noted months after Descemet membrane endothelial keratoplasty had been performed in both cases; explantation was required. Laboratory analysis of the IOLs confirmed calcification of the anterior surfaces in a localized pattern in the area of the capsulorhexis or pupil.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Clinical results with a supplementary toric intraocular lens for the correction of astigmatism in pseudophakic patients

PURPOSE

To evaluate the visual outcomes of pseudophakic patients who underwent supplementary toric intraocular lens (IOL) implantation to correct astigmatic refractive errors.

METHODS

Pseudophakic patients referred for the implantation of a supplementary toric IOL (Sulcoflex Toric 653T) were evaluated. Uncorrected and corrected distance visual acuities (UDVA and CDVA, respectively), spherical equivalent (SE) refraction, rotational stability, higher order aberrations (HOA), and photopic glare and no-glare contrast sensitivity (CSV-1000, VectorVision) were evaluated.

RESULTS

A total of 10 eyes of 10 patients were included. The mean age was 56.42 ± 5.9 years (range 45-65 years). Mean follow-up was 6.99 ± 5.1 months (6-18 months). Postoperatively, UDVA improved to 0.10 ± 0.12 (0.3 to -0.1) (p = 0.004) and CDVA to 0.07 ± 0.12 (0.3 to -0.1) (p = 0.021). Mean SE was -0.30 ± 0.56 D (-1.00 to +0.75) (p = 0.001). Mean toric IOL axis rotation at 6-month follow-up was 3.0° ± 2.45° (0-6). Ocular aberrometry values decreased after surgery (for average HOA root mean square, p = 0.008). Photopic contrast sensitivity (for all spatial frequencies) showed a trend for improvement after surgery; however, this was not borne out from the analysis (p&gt;0.05).

CONCLUSIONS

The implantation of the Sulcoflex Toric IOL to correct astigmatism in pseudophakic patients provided excellent visual outcomes, predictability of refractive results, rotational stability, and optical performance. The implantation of this IOL is a safe and effective technique to correct pseudophakic cylindrical refractive errors and reduce spectacle dependence in these patients.

Surgical options for correction of refractive error following cataract surgery

Refractive errors are frequently found following cataract surgery and refractive lens exchange. Accurate biometric analysis, selection and calculation of the adequate intraocular lens (IOL) and modern techniques for cataract surgery all contribute to achieving the goal of cataract surgery as a refractive procedure with no refractive error. However, in spite of all these advances, residual refractive error still occasionally occurs after cataract surgery and laser in situ keratomileusis (LASIK) can be considered the most accurate method for its correction. Lens-based procedures, such as IOL exchange or piggyback lens implantation are also possible alternatives especially in cases with extreme ametropia, corneal abnormalities, or in situations where excimer laser is unavailable. In our review, we have found that piggyback IOL is safer and more accurate than IOL exchange. Our aim is to provide a review of the recent literature regarding target refraction and residual refractive error in cataract surgery.

Management of residual refractive error after cataract surgery

PURPOSE OF REVIEW

To provide a review of the recent literature on the management of residual refractive error after cataract surgery.

RECENT FINDINGS

Laser in-situ keratomileusis (LASIK) is the most accurate procedure to correct residual refractive error after cataract surgery. Lens-based procedures, such as intraocular lens (IOL) exchange or piggyback lens implantation, are also possible alternatives in cases with extreme ametropia, corneal abnormalities, or in situations where excimer laser is not available. In this review, we found that Piggyback IOL were safer and more accurate than IOL exchange.

SUMMARY

Emmetropia is our main target today in modern cataract surgery. Accurate biometric analysis, selection and calculation of the adequate IOL, and modern techniques for cataract surgery all help surgeons to move toward the goal of cataract surgery as a refractive procedure free from refractive error. However, in spite of all these inputs, residual refractive error still occasionally occurs after cataract surgery and LASIK seems to be the most accurate method for its correction.