1stQ AddOn lens: benefits, limitations and how it works
The 1stQ AddOn is a supplementary (also known as a piggy back) intraocular lens from the Medicontur Group. It sits behind the iris, in front of the original cataract lens implant. Depending on the model, it can correct a remaining glasses prescription, treat regular astigmatism, or add intermediate and near focus to a monofocal implant.
An AddOn does not replace the original lens and does not guarantee freedom from glasses. The trifocal versions divide light between several focuses, which can produce haloes and affect contrast. All versions require another implant in the eye, with surgical risks and a need for suitable anatomy.
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What sort of vision is 1stQ AddOn designed to provide?
The monofocal AddOn mainly corrects a remaining distance prescription after cataract surgery. Reading glasses are usually still needed if both eyes are aimed for distance. The toric monofocal version also corrects regular astigmatism, where the cornea has different curvature in different directions.
A trifocal AddOn adds intermediate and near focuses to an existing monofocal lens. These may help with a computer, phone or reading, as well as distance tasks. Working distance, lighting and the prescription in each eye matter; small print or sustained reading can still need glasses. Neither version restores the natural lens’s ability to change focus.
Further explanation: Rayner Sulcoflex lens: benefits, limitations and how it works.
How does its optical design work?
AddOn is designed specifically for the ciliary sulcus, a supporting space behind the iris. Its four closed-loop supports, called haptics, help position the lens. The front surface is convex and the back surface concave, allowing separation from the original implant. A routine one-piece lens designed for the capsular bag should not be substituted for a purpose-designed sulcus lens.
Monofocal optics bend light towards one principal focus. Trifocal optics use a central diffractive pattern to distribute light among distance, intermediate and near focuses. More useful near vision comes with an optical compromise: light is shared, and bright lights may produce rings or glare.
A supplementary lens can be implanted after the first operation, or with a monofocal implant in a planned two-lens, or “duet”, procedure. The supplementary-lens guide explains these approaches.
What is the lens made of?
The lens is a single-piece, foldable hydrophilic acrylic implant containing about 25% water, with an ultraviolet absorber. Hydrophilic means that its material takes up water. This allows it to be folded for insertion; ultraviolet filtering does not establish protection against macular degeneration.
What are its technical specifications?
D means dioptres, a unit of optical power. Cylinder power describes astigmatism correction at the implant plane, which differs from a glasses prescription.
| Feature | Specification |
|---|---|
| Manufacturer / family | 1stQ / Medicontur Group; supplementary AddOn lenses |
| Implant position | Ciliary sulcus, behind the iris and in front of a primary capsular-bag IOL |
| Optic / overall span | 6.0 mm / 13.0 mm |
| Construction / material | Single-piece hydrophilic acrylic; 25% water; ultraviolet absorber |
| Supports / shape | Four closed-loop haptics, 0° angulation; convex–concave optic |
| Monofocal spherical range | −10.0 to +10.0 D, in 0.25 D steps |
| Trifocal spherical range | −5.0 to +5.0 D; trifocal toric spherical equivalent −3.0 to +3.0 D |
| Toric cylinder range | Monofocal toric up to +11.0 D; trifocal toric +1.0 to +4.5 D at the IOL plane; combinations depend on model |
| Trifocal near addition | +3.0 D at the IOL plane; actual reading distance depends on the combined eye optics |
| Delivery | Folded insertion using a compatible injector selected for the exact model and power |
Is there a toric version for astigmatism?
Yes, a toric version is available in Australia for both monofocal and trifocal AddOn options. The monofocal toric corrects the remaining prescription and regular astigmatism; the trifocal toric also adds intermediate and near focuses.
A toric implant must sit at its calculated angle. Four-point support does not guarantee that it will never rotate: a published Australian series required repositioning in two of 22 eyes. Irregular corneal astigmatism and unstable measurements need separate assessment.
When was 1stQ AddOn introduced in Australia?
Sales of the AddOn family began in 2016.
What are the main advantages?
- Correction without removing the original implant. A suitable AddOn can address a remaining prescription while leaving a stable capsular-bag lens in place.
- A near-vision option after a monofocal implant. A trifocal AddOn can broaden the useful range of vision, although the supporting studies are small.
- A toric option. Selected eyes can have residual regular astigmatism corrected along with spherical prescription.
- Flexibility if needs change. The supplementary lens can potentially be removed or exchanged separately. This still involves surgery and is not a risk-free reversal.
What are the main limitations and uncertainties?
- Glasses may remain useful. A lens cannot guarantee comfortable vision for every task or lighting condition.
- Trifocal optics have trade-offs. Haloes, glare and reduced contrast may matter particularly for night driving. A monofocal AddOn does not introduce the same diffractive near-focus pattern.
- A second implant adds complexity. The lens can rotate, become decentered, rub against the iris or become caught at the pupil edge. Further treatment may be needed.
- Eye health sets the ceiling. Dry eye, corneal irregularity, macular disease or optic nerve damage may explain disappointing vision and will not be corrected simply by adding a lens.
- The evidence is limited. Small observational studies cannot reliably quantify rare complications, lifetime durability or superiority over other treatments.
What have clinical studies found?
The studies support AddOn as an option for selected eyes, but results from one optical version cannot be applied to the whole family.
Trifocal vision after an existing implant
A 2020 study followed 18 eyes of 11 patients receiving a trifocal supplementary lens for six months. Participants reported spectacle independence and useful vision across several distances.
A Sydney comparison of two-lens and single-lens surgery
A retrospective study compared 32 eyes of 18 patients receiving a monofocal lens plus a trifocal AddOn with 57 eyes of 35 patients receiving a single trifocal lens. Uncorrected distance and near acuity did not differ significantly between groups at one month and one year. Intermediate acuity was not measured. One AddOn eye developed pupillary capture, corrected before discharge.
Residual astigmatism and longer follow-up
An Australian toric monofocal series of 22 eyes in 17 patients found improved uncorrected distance vision and reduced astigmatism, but two eyes required rotational repositioning. A separate 2025 report followed 14 eyes in 12 patients with monofocal AddOn lenses for about three years on average. It reported improved uncorrected distance vision without observed chronic inflammation, pressure elevation or pigment dispersion.
Who might find 1stQ AddOn a good fit?
An AddOn may suit someone with a stable, well-positioned primary implant and a remaining prescription that is affecting daily life. A trifocal version adds a separate decision about near-vision priorities and tolerance of haloes or reduced contrast. Assessment includes the tear film, cornea, macula, optic nerve, pupil and space behind the iris.
Loose lens-supporting fibres and iris adhesions to the capsular bag are listed as contraindications. A primary capsular tension ring and pigment dispersion, with or without glaucoma, require particular caution. A diffractive AddOn is not recommended over a diffractive primary lens.
A small study has also explored AddOn for negative dysphotopsia, a dark peripheral shadow. That is a different problem from a remaining prescription.
What are the alternatives?
Glasses or contact lenses may provide the required correction without another operation. A corneal laser treatment may suit some stable prescriptions, depending on the cornea and tear film. Lens exchange changes the original implant but has a different surgical risk profile, particularly once the capsule has been opened.
Other supplementary lens designs, including Sulcoflex, have different haptics, power ranges and evidence. If cataract surgery has not yet taken place, a single implant chosen from the main lens categories may be preferable to a planned duet. There is no single best approach for all eyes.
What risks and follow-up should I understand?
Another intraocular operation carries risks including infection, inflammation, bleeding, pressure problems, damage to the cornea or iris, retinal complications and a result that differs from the intended prescription. AddOn-specific concerns include rotation, displacement, pupillary capture, iris rubbing and clouding between or within the lenses. Follow-up checks vision, prescription, pressure, inflammation and lens position.
Capsule clouding behind the original implant is different from AddOn material clouding. YAG capsulotomy treats appropriate capsule clouding. Discuss possible lens exchange before YAG because opening the capsule can make an exchange more complex.
What does the historical recall mean?
In 2017, a voluntary recall affected specified batches of the spherical monofocal A4SW00 AddOn after fibrin or inflammatory reactions with suspected toxic anterior segment syndrome, an acute inflammatory reaction. The notice did not call for removal of already implanted lenses. The precise implant model and batch matter when interpreting a safety notice.
What should I ask before choosing this lens?
- What is causing my current visual difficulty, and which parts can an AddOn address?
- Which exact model is proposed: monofocal, toric, trifocal or trifocal toric?
- What vision is being targeted in each eye, and which tasks may still need glasses?
- How might haloes, contrast changes or night driving affect my choice?
- Are my original implant, capsular support and likely future operations suitable?
- Why choose this over glasses, laser correction or lens exchange, and what is the plan if the result disappoints?
When should I seek urgent advice after surgery?
Seek urgent advice for increasing pain, marked redness, a sudden drop in vision, new flashes or floaters, or a shadow or curtain in the vision. Contact your ophthalmologist urgently, or attend an emergency department. Do not assume these symptoms are ordinary adjustment to the implant.
Sources and further reading
- 1stQ. AddOn current brochure, revision 2024-V03-11/2025: model-specific technical tables.
- 1stQ. AddOn instructions for use, June 2026 revision 03, posted July 2026.
- TGA. ARTG 280510: 1stQ posterior-chamber intraocular lens; SurgiVision sponsor.
- Australian Government. Prescribed List, effective 1 July 2026: AddOn VU022–VU025.
- Palomino Bautista C et al. Spectacle Independence for Pseudophakic Patients — Experience with a Trifocal Supplementary Add-On Intraocular Lens. Clinical Ophthalmology (2020).
- Harrisberg B et al. Primary duet versus single trifocal intraocular lens implantation: visual outcomes. Clinical Ophthalmology (2023).
- Gundersen KG, Potvin R. Refractive and visual outcomes after toric supplementary IOL implantation. Clinical Ophthalmology (2020).
- McLintock CA et al. Outcomes of toric supplementary intraocular lenses for residual astigmatism. Current Eye Research (2022); abstract.
- Argay A et al. Long-term results of 1stQ AddOn monofocal implantation (2025); English abstract.
- Van Slycken M et al. Supplementary sulcus lens for negative dysphotopsia (2023).
- 1stQ. Restricted A4SW00 field safety notice, 22 February 2017; BfArM-hosted.
- Australian product information. 1stQ AddOn, March 2026; SurgiVision supply information.
- Apel A, Harrisberg B. 1stQ Secondary Sulcus Supplementary IOLs: Innovative Applications For Multifocal Correction. mivision (1 November 2020); reported Australian family sales history.