Special Cases: Secondary Piggy-Back Lenses

1. 1. 1. Piggyback / Supplementary Intraocular Lens Implantation (EyeWiki)

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Article initiated by:

Joana Portelinha, MD, Tiago Luís do Carmo Bravo Ferreira, MD

All contributors:

Joana Portelinha, MD, Vandana Reddy, MD, Brian Shafer, MD

Assigned editor:

Brian Shafer, MD

Review:

Assigned status Up to Date

 by Brian Shafer, MD on August 7, 2026.

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Contributing Editors:	add

Introduction

Residual refractive error after cataract surgery remains a common source of patient dissatisfaction, and expectations have risen substantially with the widespread use of premium intraocular lenses (IOLs). Surgical options for correcting pseudophakic ametropia include IOL exchange, corneal refractive surgery (LASIK or PRK), and implantation of a secondary IOL anterior to the primary lens.Khoramnia R, Kahraman G, Amon M, et al. Polypseudophakia: from "piggyback" to supplementary sulcus-fixated IOLs. Graefes Arch Clin Exp Ophthalmol. 2025;263(3):609-620.Fernández-Buenaga R, Alió JL, Pérez Ardoy AL, et al. Resolving refractive error after cataract surgery: IOL exchange, piggyback lens, or LASIK. J Refract Surg. 2013;29(10):676-683.

The term polypseudophakia describes the use of two IOLs in the same eye. Historically this was accomplished by the classic piggyback technique, in which both lenses were placed in the capsular bag, or by placing a lens designed for the capsular bag into the ciliary sulcus. Both of these earlier approaches have been largely discredited because of unacceptable complication rates. Modern practice uses IOLs specifically designed for ciliary sulcus fixation, and the contemporary literature advocates replacing the term "piggyback" with "supplementary IOL" or "secondary enhancement" to distinguish these fundamentally different procedures.

Principal indications for supplementary IOL implantation are:

• Residual myopic or hyperopic pseudophakic ametropia*
• Residual pseudophakic astigmatism*
• Pseudophakic presbyopia (secondary enhancement of a monofocal pseudophake to multifocal or trifocal vision)*
• Post-keratoplasty ametropia and astigmatism, particularly while sutures remain in place*
• Extreme hyperopia or microphthalmos requiring power beyond the range of a single available IOL*
• Temporary and adjustable correction in growing or refractively unstable eyes, a use case unique to the reversibility of the technique*

History

The technique was first described in 1993 by Gayton and Sanders in an eye with cataract and microphthalmos in which the calculated IOL power was +46 D, exceeding available single-lens options.Gayton JL, Sanders VN. Implanting two posterior chamber intraocular lenses in a case of microphthalmos. J Cataract Refract Surg. 1993;19(6):776-777.

The application was subsequently extended to pseudophakic refractive error. In a 1999 prospective series of 8 normal pseudophakic eyes and 7 post-penetrating keratoplasty pseudophakic eyes, implantation of a second IOL anterior to the first reduced mean absolute deviation from emmetropia from 3.38 D to 1.21 D, and the proportion of eyes with uncorrected acuity of 20/40 or better rose from 7% to 50%.Gayton JL, Sanders V, Van der Karr M, Raanan MG. Piggybacking intraocular implants to correct pseudophakic refractive error. Ophthalmology. 1999;106(1):56-59.

Recognition of interlenticular opacification as a specific complication of in-the-bag piggyback lenses in 2000 drove the shift toward sulcus placement and, ultimately, toward purpose-designed supplementary lenses.Gayton JL, Apple DJ, Peng Q, et al. Interlenticular opacification: clinicopathological correlation of a complication of posterior chamber piggyback intraocular lenses. J Cataract Refract Surg. 2000;26(3):330-336.

Terminology

Term	Definition	Current status
Classic piggyback	Both IOLs implanted in the capsular bag	Largely abandoned — high rate of interlenticular opacification
Secondary piggyback	Capsular-bag-designed IOL placed in the sulcus anterior to an existing bag IOL	Discouraged — risk of iris chafe, pigment dispersion, UGH syndrome
Supplementary IOL / secondary enhancement	IOL specifically engineered for ciliary sulcus fixation, placed anterior to a bag IOL	Preferred contemporary approach
DUET	Planned two-lens strategy (monofocal in bag plus removable multifocal supplementary IOL in sulcus)	Increasingly used for reversible presbyopia correction

Lens Types and Designs

Supplementary IOLs are available in monofocal, toric, multifocal/trifocal, and multifocal toric models. Three platforms were specifically designed for ciliary sulcus implantation.

Design principles

All purpose-built supplementary IOLs share features intended to prevent the complications of earlier techniques:

• Convex-concave (meniscus) optic — vaults the lens anteriorly away from the primary IOL, maximizing the interlenticular space and preventing interlenticular opacification and unpredictable refractive interaction*
• Large optic diameter (6.0–7.0 mm) and overall length (13.0–14.0 mm) — provides stable sulcus fixation and resists pupillary optic capture*
• Rounded, smooth anterior optic and haptic edges — minimizes posterior iris chafing, pigment dispersion, and pigmentary glaucoma*
• Posterior haptic angulation or planar haptics with undulation — maintains clearance from the iris and provides rotational stability for toric models*

These features directly address the pathologic findings documented with inappropriate sulcus lenses, in which thick square-edged haptics and square anterior optic edges produce iris transillumination defects, pigment dispersion, elevated intraocular pressure, and recurrent hemorrhage.Miller KM, Oetting TA, Tweeten JP, et al. Cataract in the Adult Eye Preferred Practice Pattern. American Academy of Ophthalmology; 2022.Kirk KR, Werner L, Jaber R, et al. Pathologic assessment of complications with asymmetric or sulcus fixation of square-edged hydrophobic acrylic intraocular lenses. Ophthalmology. 2012;119(5):907-913.

Sulcoflex (Rayner)

One-piece hydrophilic acrylic, undulating haptics, 10° posterior haptic angulation, optic diameter 6.50 mm, overall length 14.0 mm, convex-concave optic.

• Sulcoflex Aspheric (653L) — sphere −5.0 to −0.50 D and +0.50 to +5.0 D in 0.50 D increments*
• Sulcoflex Toric (653T) — spherical equivalent −3.0 to +3.0 D in 0.50 D increments; cylinder +1.0 to +3.0 D in 1.0 D increments*
• Sulcoflex Multifocal (653F) — +3.50 D add at the IOL plane (≈+3.0 D at the spectacle plane); sphere −3.0 to +3.0 D in 0.50 D steps*
• Sulcoflex Trifocal — later addition providing distance, intermediate, and near correction*

Add-On (HumanOptics)

Three-piece foldable lens with a silicone elastomer optic incorporating a UV absorber, optic diameter 7.0 mm, overall length 14.0 mm, convex-concave optic with a round anterior edge to prevent iris irritation. Modified C-loop haptics of high-molecular-weight PMMA with zero-degree angulation.

• SECURA-sPB (monofocal) — sphere −6.0 to +6.0 D in 0.50 D increments*
• DIFFRACTIVA-sPB (multifocal) — +3.50 D add; sphere −6.0 to +6.0 D in 0.50 D steps*
• TORICA-sPB — sphere −6.0 to +3.0 D in 0.50 D steps, and in 1.0 D steps from −30.0 to −7.0 D and +4.0 to +6.0 D; cylinder +1.0 to +3.0 D in 1.0 D steps*
• TORICA-DIFF-sPB — sphere −3.0 to +3.0 D in 0.50 D steps; cylinder +1.0 to +4.0 D in 0.50 D increments*

1stQ AddOn (1stQ / Medicontur)

One-piece foldable hydrophilic acrylic, optic diameter 6.0 mm, overall length 13.0 mm, convex-concave optic with four flexible haptics.

• AddOn refractive (A4SW00) — sphere −10.0 to +10.0 D in 0.25 D steps*
• AddOn toric (6 models) — sphere −10.0 to +10.0 D in 0.25 D steps; cylinder +1.5 to +9.0 D in 0.75 D steps and +9.0 to +11.0 D in 1.0 D steps*
• AddOn progressive (3 models) — +3.0 D add; sphere −3.0 to +3.0 D in 0.25–0.50 D steps*
• AddOn trifocal — provides distance, intermediate, and near vision*

Intraocular Lens Power Calculation

A major practical advantage of the supplementary IOL is that its power is derived directly from the patient's manifest refraction, so the power of the primary IOL need not be known and biometric error in axial length or keratometry does not propagate into the calculation.Habot-Wilner Z, Sachs D, Cahane M, et al. Refractive results with secondary piggyback implantation to correct pseudophakic refractive errors. J Cataract Refract Surg. 2005;31(11):2101-2103.

Vertex-related ratios

The required IOL-plane power exceeds the spectacle-plane refractive error, and the relationship is not a fixed constant. In a theoretical modeling study using schematic eyes across a range of pseudophakic anterior chamber depths, sphere values, and cylinder values:

• The spherical ratio (IOL-plane to spectacle-plane) ranged from 1.01 to 1.61*
• The toric ratio ranged from 0.88 to 1.60*
• Use of a fixed ratio — as employed by some manufacturer online calculators — can produce errors of up to 1 DBuonsanti D, Hoffer KJ, Coutinho CP, Savini G. The influence of anterior chamber depth on the calculation of piggyback intraocular lenses. Am J Ophthalmol. 2025;272:1-8.*

The direction of error is predictable: undercorrection in eyes with a deep anterior chamber and low sphere/cylinder, and overcorrection in eyes with a shallow anterior chamber and high preoperative sphere and/or cylinder. Pseudophakic anterior chamber depth should therefore be measured and, where possible, a calculator that varies the ratio according to measured parameters should be used.

Practical rules of thumb

Widely used approximations, which should be regarded as starting points rather than substitutes for a proper calculation:

• Hyperopic correction: IOL power ≈ 1.5 × spectacle-plane spherical error*
• Myopic correction: IOL power ≈ 1.2 × spectacle-plane spherical error*
• Toric models: cylinder is specified at the IOL plane and the axis is aligned to the refractive cylinder axis, not the keratometric axis, because the residual astigmatism being treated includes any contribution from the primary IOL*

More generally, sulcus placement positions the optic more anteriorly; for a standard secondary IOL the AAO advises that sulcus IOL power be reduced by 0.5 to 1.0 D relative to the capsular bag calculation (with a smaller reduction when the optic is captured through the capsulorhexis).

Preoperative Evaluation

• Confirm refractive stability and verify the manifest refraction on at least two occasions; a discrepancy between manifest refraction and biometry should prompt a search for an alternative cause of blurred vision.*
• Exclude non-refractive causes of dissatisfaction — posterior capsule opacification, cystoid macular edema, epiretinal membrane, ocular surface disease, and IOL decentration or tilt. Treat these before considering a supplementary lens.*
• Assess the primary IOL and capsular bag: the supplementary IOL is appropriate only when the primary IOL is well centered and stable within an intact capsular bag. Inadequate capsular support, significant zonulopathy, or a decentered primary IOL favors exchange or scleral/iris fixation.*
• Measure sulcus dimensions and anterior chamber depth — a shallow anterior chamber or narrow angle increases the risk of iris chafe and IOP elevation. Ultrasound biomicroscopy and anterior segment OCT are useful for assessing lens–iris contact.Mehta R, Aref AA. Intraocular lens implantation in the ciliary sulcus: challenges and risks. Clin Ophthalmol. 2019;13:2317-2323.*
• Endothelial cell count, particularly in post-keratoplasty eyes and shallow anterior chambers.*
• Evaluate the posterior capsule. Nd:YAG capsulotomy is more difficult after a supplementary IOL is in place, and vitreous prolapse risk rises; where capsulotomy is anticipated, consider performing it before supplementary implantation.*
• Glaucoma status and pigment dispersion — a history of pigment dispersion syndrome or uncontrolled glaucoma is a relative contraindication.*

Surgical Technique

1. Pupil dilation with phenylephrine 10% and tropicamide 1%.

1. Clear corneal incision, sized to the implant: approximately 2.2 mm for the 1stQ AddOn, 3.0 mm for the Sulcoflex using the Rayner single-use soft-tipped injector, and 3.2 mm for the HumanOptics Add-On.

1. Ophthalmic viscosurgical device is used to deepen the anterior chamber and, critically, to open the space between the anterior capsule and the posterior iris surface, creating room for the haptics.

1. Implantation with an injector (Sulcoflex, 1stQ AddOn) or forceps (HumanOptics Add-On), with the haptics directed into the ciliary sulcus. Correct orientation of the convex-concave optic must be confirmed.

1. Toric alignment to the marked refractive cylinder axis, using preoperative reference marking or an intraoperative image-guidance system.

1. Complete OVD removal, including from between the two optics — retained viscoelastic in the interlenticular space is a recognized cause of early IOP spike.

1. Wound hydration and intracameral cefuroxime.

Postoperatively, patients receive topical antibiotic, corticosteroid, and NSAID. Day-1 IOP measurement is essential given the risk of pressure elevation from retained OVD or pigment release.

Outcomes

Refractive predictability

• In a prospective series of 12 eyes receiving the Sulcoflex 653L, mean spherical equivalent improved from −1.25 ± 0.25 D to −0.25 ± 0.40 D, uncorrected distance acuity improved in all eyes, and no significant intraoperative or postoperative complications occurred over 17 months of follow-up.Kahraman G, Amon M. New supplementary intraocular lens for refractive enhancement in pseudophakic patients. J Cataract Refract Surg. 2010;36(7):1090-1094.*
• In a prospective series of 10 eyes with sulcus-placed secondary IOLs, mean preoperative myopia of −6.6 ± 3.3 D and hyperopia of +3.8 ± 0.8 D were corrected to within 0.5 ± 0.7 D and 0.46 ± 0.4 D of target respectively, with best spectacle-corrected acuity improving from 20/44 to 20/30 (P *

Comparison with IOL exchange

A prospective comparative series of 23 eyes (12 secondary piggyback vs 11 IOL exchange) with 18–20 months of follow-up found:

Outcome	Secondary piggyback	IOL exchange
Myopic eyes: mean SE	−6.2 ± 2.2 D → −0.28 ± 0.59 D	−5.88 ± 3.1 D → +0.16 ± 1.09 D
Hyperopic eyes: mean SE	+4.79 ± 1.02 D → +0.03 ± 0.74 D	+5.05 ± 0.93 D → +0.11 ± 0.69 D
Within ±0.5 D of target	92%	82%
Complications	None reported	1 posterior capsule rupture; 1 eye lost 1 line CDVA

Data from El Awady and Ghanem.El Awady HE, Ghanem AA. Secondary piggyback implantation versus IOL exchange for symptomatic pseudophakic residual ametropia. Graefes Arch Clin Exp Ophthalmol. 2013;251(7):1861-1866.

Comparison with corneal laser enhancement

A retrospective multicenter study of 65 eyes compared IOL exchange (17 eyes), piggyback lens (20 eyes), and LASIK (28 eyes) for post-cataract refractive error. Predictability within ±1.0 D of target spherical equivalent was 62.5% for IOL exchange, 85% for the piggyback lens, and 100% for LASIK. Median efficacy index was 0.58, 0.75, and 0.91 respectively, with LASIK significantly better than both intraocular approaches (P = .004 and P = .003). LASIK also achieved significantly greater reduction in refractive cylinder than either intraocular option. No significant difference in safety index was found among the three groups (P = .094).

These data support corneal laser enhancement as the most predictable option when the cornea is suitable, with supplementary IOL implantation preferred when the cornea is not — thin or irregular corneas, prior keratoplasty, ectatic disease, severe dry eye, or a large residual error beyond safe ablation limits.

Presbyopia correction and secondary enhancement

In 18 eyes of 11 pseudophakic patients with prior monofocal bag IOLs who received the trifocal 1stQ AddOn:

• 83.3% were within ±0.5 D of emmetropia and 100% within ±1.0 D of target*
• Mean uncorrected distance, intermediate, and near acuities were 0.03, 0.21, and 0.12 logMAR respectively*
• All patients achieved spectacle independence at all distances*
• Depth of focus (0.486 D) was equivalent to a trifocal capsular bag IOL, while the defocus curve was superior in the intermediate and near ranges*
• No adverse change in endothelial cell density, IOP, or angle structures; all lenses were well positioned in the sulcusPalomino-Bautista C, Sánchez-Jean R, Carmona Gonzalez D, Romero Domínguez M, Castillo Gómez A. Spectacle independence for pseudophakic patients — experience with a trifocal supplementary add-on intraocular lens. Clin Ophthalmol. 2020;14:1043-1054.*

Post-keratoplasty and post-refractive-surgery eyes

Supplementary IOLs are particularly valuable after penetrating keratoplasty, where sutures must remain for a year or more and keratorefractive correction of induced astigmatism must therefore be deferred. A planned two-stage approach has also been described in eyes with prior radial keratotomy, where IOL power calculation is notoriously unpredictable: a small-aperture posterior chamber IOL was implanted at cataract surgery with a planned secondary sulcus supplementary IOL for the anticipated residual error, achieving −0.10 logMAR uncorrected acuity bilaterally with complete spectacle independence.Barnett V, Barsam A, Than J, Srinivasan S. Small-aperture intraocular lens combined with secondary piggyback intraocular lens during cataract surgery after previous radial keratotomy. J Cataract Refract Surg. 2018;44(8):1042-1045.

Complications

Interlenticular opacification (ILO)

ILO is the defining complication of the classic in-the-bag piggyback technique and is the principal reason it has been abandoned. Histopathologic analysis of explanted piggyback pairs demonstrates that the opacifying material consists of retained and regenerative lens epithelial cells, cortical material, and Elschnig pearls proliferating from the equatorial Soemmering ring into the interlenticular space — a pathogenesis analogous to posterior capsule opacification.Werner L, Apple DJ, Pandey SK, et al. Analysis of elements of interlenticular opacification. Am J Ophthalmol. 2002;133(3):320-326.

• Clinically it produces decreased best-corrected acuity and a hyperopic shift.Fenzl RE, Gills JP, Gills JP. Piggyback intraocular lens implantation. Curr Opin Ophthalmol. 2000;11(1):73-76.*
• The material is graded from thick cortical material peripherally, through globules undergoing liquefactive degeneration midperipherally, to a compact amorphous layer paracentrally, with the central contact zone typically clear.*
• In a rabbit model, ILO was significantly associated with pairs of single-piece hydrophobic acrylic lenses in the bag, whereas silicone plate-haptic pairs and a dual-optic silicone IOL showed relatively little ILO.Werner L, Mamalis N, Stevens S, et al. Interlenticular opacification: dual-optic versus piggyback intraocular lenses. J Cataract Refract Surg. 2006;32(4):655-661.*
• Explantation is technically demanding, as the IOL complex becomes densely adherent to the capsular bag and requires separation with high-viscosity OVD.Eleftheriadis H, Marcantonio J, Duncan G, Liu C. Interlenticular opacification in piggyback AcrySof intraocular lenses: explantation technique and laboratory investigations. Br J Ophthalmol. 2001;85(7):830-833.*

Prevention rests on three measures identified in the original clinicopathologic series: meticulous cortical cleanup especially at the equator, a relatively large continuous curvilinear capsulorhexis to sequester retained cells peripheral to the optic, and — most importantly — placing the anterior IOL in the ciliary sulcus rather than the bag to isolate retained cells from the interlenticular space. The convex-concave optic of purpose-designed supplementary lenses further increases interlenticular separation.

Pigment dispersion, iris chafe, and UGH syndrome

Posterior iris chafing by the optic or haptics of a sulcus-fixated lens produces a spectrum of disease: iris pigment epithelial transillumination defects, pigment dispersion with or without IOP elevation, intermittent microhyphema with transient visual obscurations, and frank uveitis-glaucoma-hyphema (UGH) syndrome.Masket S. Pseudophakic posterior iris chafing syndrome. J Cataract Refract Surg. 1986;12(3):252-256.

Single-piece acrylic IOLs are contraindicated in the ciliary sulcus. The AAO Cataract in the Adult Eye Preferred Practice Pattern states that single-piece acrylic IOLs currently available in the United States are contraindicated in the sulcus because of IOL decentration and iris chafing causing transillumination defects, pigment dispersion, elevated IOP, recurrent hyphema, and inflammation. Histopathologic study of 661 pseudophakic cadaver eyes confirmed IOL decentration and tilt, anterior segment pigment dispersion, iris transillumination defects, iris pigment epithelial disruption and atrophy, synechiae, and haptic loop erosion in eyes with out-of-the-bag fixation of square-edged hydrophobic acrylic lenses.

A clinical series of 23 eyes with secondary sulcus transscleral fixation of a single-piece hydrophobic acrylic lens reported pigment dispersion syndrome in 17 eyes and pigmentary glaucoma in 7 eyes, with ultrasound biomicroscopy demonstrating close apposition of the optic to the posterior iris and reverse pupillary block in 10 eyes.Tong N, Liu F, Zhang T, et al. Pigment dispersion syndrome and pigmentary glaucoma after secondary sulcus transscleral fixation of single-piece foldable posterior chamber intraocular lenses in Chinese aphakic patients. J Cataract Refract Surg. 2017;43(5):639-644.

Purpose-designed supplementary IOLs mitigate but do not abolish this risk; long-term monitoring of IOP, gonioscopic pigment, and iris transillumination remains necessary.

Elevated intraocular pressure

IOP elevation may be early (retained OVD, including from the interlenticular space, or steroid response) or late (pigmentary glaucoma, pupillary block). Pupillary block glaucoma has been specifically reported in association with a secondary piggyback IOL.

Pupillary optic capture

Capture of the supplementary optic through the pupil, typically after pharmacologic or physiologic mydriasis, is prevented by the large optic diameter of the Sulcoflex and HumanOptics designs and by the square four-haptic design of the 1stQ AddOn.

Other complications

• Decentration and tilt — noncapsular fixation increases the potential for both, which is a specific reason for caution when considering multifocal optics or lenses with high negative spherical aberration in the sulcus.*
• Toric rotation — mitigated by haptic undulation and terminal design features providing rotational stability.*
• Endothelial cell loss — a concern in shallow chambers, though contemporary series report no significant change.*
• Dysphotopsia with multifocal supplementary optics, which is nonetheless reversible by explantation — a distinctive advantage of the technique.*
• Difficulty with subsequent Nd:YAG capsulotomy and reduced fundus visualization or laser access.*

Advantages

1. Avoids the trauma of IOL exchange. Explantation of a lens implanted years earlier, with marked capsular fibrosis, risks capsular rupture with vitreous loss, retinal tears or detachment, cystoid macular edema, zonular damage, and cyclodialysis, and makes accurate power selection for the replacement lens more difficult.

1. Power calculation is based purely on the manifest refraction, so the primary IOL power need not be known and biometric error is not compounded.

1. Reversible and adjustable. The supplementary lens can be explanted or exchanged with relative ease, which permits patients to trial multifocality and allows temporary correction in growing or refractively unstable eyes.

1. Wide dioptric range, exceeding what is safely correctable by corneal ablation, and applicable when the cornea is unsuitable for laser refractive surgery.

1. Stable long-term refractive results compared with corneal ablation in eyes at risk of regression.

Limitations and Contraindications

• Inadequate capsular support, a decentered or unstable primary IOL, or significant zonulopathy*
• Shallow anterior chamber or narrow angle*
• Pre-existing pigment dispersion syndrome or uncontrolled glaucoma*
• Low endothelial cell count*
• Active uveitis*
• Astigmatism better addressed at the corneal plane in an eye with a healthy, regular cornea, given the superior predictability of LASIK for cylinder*

Additional Resources

• Yeu E. Intraocular Implants (IOLs). American Academy of Ophthalmology. EyeSmart/Eye health.*
• American Academy of Ophthalmology. Cataract in the Adult Eye Preferred Practice Pattern.*